Add apps for DevBytes, MarsRealEstate

DevBytesRepository/README.md

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+DevByteRepository - Solution Code
+==================================
+
+Solution code for the Repository codelab.
+
+Introduction
+------------
+
+DevByteRepository app displays a list of DevByte videos. DevByte videos are
+short videos made by the Google Android developer relations team to introduce
+new developer features on Android. This app demonstrates the Repository pattern,
+the recommended best practice for code separation and architecture. Using
+repository pattern the data layer is abstracted from the rest of the app.
+Repositories act as mediators between different data sources, such as persistent
+models, web services, and caches and the rest of the app.
+
+Pre-requisites
+--------------
+
+You need to know:
+- How to open, build, and run Android apps with Android Studio.
+- The basic Android Architecture Components, ViewModel, and LiveData.
+- The data persistence library, Room.
+- Building and launching a coroutine.
+- Read the logs using the Logcat.
+- Binding adapters in data binding.
+- Using the Retrofit networking library.
+
+
+Getting Started
+---------------
+
+1. Download and run the app.
+2. You need Android Studio 3.4 or higher to build this project.
+
+License
+-------
+
+Copyright 2019 Google, Inc.
+
+Licensed to the Apache Software Foundation (ASF) under one or more contributor
+license agreements.  See the NOTICE file distributed with this work for
+additional information regarding copyright ownership.  The ASF licenses this
+file to you under the Apache License, Version 2.0 (the "License"); you may not
+use this file except in compliance with the License.  You may obtain a copy of
+the License at
+
+  http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.  See the
+License for the specific language governing permissions and limitations under
+the License.

DevBytesRepository/app/build.gradle

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+/*
+ * Copyright (C) 2019 Google Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+apply plugin: 'com.android.application'
+apply plugin: 'kotlin-android'
+apply plugin: 'kotlin-kapt'
+apply plugin: "androidx.navigation.safeargs"
+apply plugin: 'kotlin-android-extensions'
+
+android {
+    compileSdkVersion 28
+    defaultConfig {
+        applicationId "com.example.android.devbyteviewer"
+        minSdkVersion 19
+        targetSdkVersion 28
+        versionCode 1
+        versionName "1.0"
+        testInstrumentationRunner "androidx.test.runner.AndroidJUnitRunner"
+        vectorDrawables.useSupportLibrary = true
+    }
+    buildTypes {
+        release {
+            minifyEnabled true
+            proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
+        }
+    }
+
+    dataBinding {
+        enabled = true
+    }
+
+}
+
+dependencies {
+    implementation fileTree(dir: 'libs', include: ['*.jar'])
+    implementation "org.jetbrains.kotlin:kotlin-stdlib-jdk7:$kotlin_version"
+
+    // support libraries
+    implementation 'androidx.appcompat:appcompat:1.0.2'
+    implementation 'androidx.legacy:legacy-support-v4:1.0.0'
+    implementation 'com.google.android.material:material:1.0.0'
+
+    // Android KTX
+    implementation 'androidx.core:core-ktx:1.0.2'
+
+    // constraint layout
+    implementation 'androidx.constraintlayout:constraintlayout:1.1.3'
+
+    // navigation
+    def nav_version = "1.0.0"
+    implementation "android.arch.navigation:navigation-fragment-ktx:$nav_version"
+    implementation "android.arch.navigation:navigation-ui-ktx:$nav_version"
+
+    // coroutines for getting off the UI thread
+    def coroutines = "1.0.1"
+    implementation "org.jetbrains.kotlinx:kotlinx-coroutines-core:$coroutines"
+    implementation "org.jetbrains.kotlinx:kotlinx-coroutines-android:$coroutines"
+
+    // retrofit for networking
+    implementation 'com.squareup.retrofit2:retrofit:2.5.0'
+    implementation 'com.jakewharton.retrofit:retrofit2-kotlin-coroutines-adapter:0.9.2'
+    implementation 'com.squareup.retrofit2:converter-moshi:2.5.0'
+
+    // moshi for parsing the JSON format
+    def moshi_version = "1.6.0"
+    implementation "com.squareup.moshi:moshi:$moshi_version"
+    implementation "com.squareup.moshi:moshi-kotlin:$moshi_version"
+    kapt "com.squareup.moshi:moshi-kotlin-codegen:$moshi_version"
+
+    // joda time library for dealing with time
+    implementation 'joda-time:joda-time:2.10'
+
+    // arch components
+    // ViewModel and LiveData
+    def lifecycle_version = "2.2.0-alpha01"
+    implementation "androidx.lifecycle:lifecycle-extensions:$lifecycle_version"
+
+    // logging
+    implementation 'com.jakewharton.timber:timber:4.7.1'
+
+    // glide for images
+    implementation 'com.github.bumptech.glide:glide:4.8.0'
+    kapt 'com.github.bumptech.glide:compiler:4.7.1'
+
+    // Room dependency
+    def room_version = "2.1.0-beta01"
+    implementation "androidx.room:room-runtime:$room_version"
+    kapt "androidx.room:room-compiler:$room_version"
+
+}

DevBytesRepository/app/proguard-rules.pro

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+# Add project specific ProGuard rules here.
+# You can control the set of applied configuration files using the
+# proguardFiles setting in build.gradle.
+#
+# For more details, see
+#   http://developer.android.com/guide/developing/tools/proguard.html
+
+# If your project uses WebView with JS, uncomment the following
+# and specify the fully qualified class name to the JavaScript interface
+# class:
+#-keepclassmembers class fqcn.of.javascript.interface.for.webview {
+#   public *;
+#}
+
+# Uncomment this to preserve the line number information for
+# debugging stack traces.
+#-keepattributes SourceFile,LineNumberTable
+
+# If you keep the line number information, uncomment this to
+# hide the original source file name.
+#-renamesourcefileattribute SourceFile

DevBytesRepository/app/src/main/AndroidManifest.xml

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+<?xml version="1.0" encoding="utf-8"?>
+<!--
+  ~ Copyright (C) 2019 Google Inc.
+  ~
+  ~ Licensed under the Apache License, Version 2.0 (the "License");
+  ~ you may not use this file except in compliance with the License.
+  ~ You may obtain a copy of the License at
+  ~
+  ~     http://www.apache.org/licenses/LICENSE-2.0
+  ~
+  ~ Unless required by applicable law or agreed to in writing, software
+  ~ distributed under the License is distributed on an "AS IS" BASIS,
+  ~ WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+  ~ See the License for the specific language governing permissions and
+  ~ limitations under the License.
+  -->
+
+<manifest xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:tools="http://schemas.android.com/tools"
+    package="com.example.android.devbyteviewer">
+
+    <uses-permission android:name="android.permission.INTERNET" />
+
+    <application
+        android:name=".DevByteApplication"
+        android:allowBackup="true"
+        android:icon="@mipmap/ic_launcher"
+        android:label="@string/app_name"
+        android:roundIcon="@mipmap/ic_launcher_round"
+        android:supportsRtl="true"
+        android:theme="@style/AppTheme"
+        tools:ignore="GoogleAppIndexingWarning">
+        <activity android:name=".ui.DevByteActivity">
+            <intent-filter>
+                <action android:name="android.intent.action.MAIN" />
+
+                <category android:name="android.intent.category.LAUNCHER" />
+            </intent-filter>
+        </activity>
+    </application>
+
+</manifest>

DevBytesRepository/app/src/main/java/com/example/android/devbyteviewer/DevByteApplication.kt

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+/*
+ * Copyright (C) 2019 Google Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.example.android.devbyteviewer
+
+import android.app.Application
+import timber.log.Timber
+
+/**
+ * Override application to setup background work via WorkManager
+ */
+class DevByteApplication : Application() {
+
+    /**
+     * onCreate is called before the first screen is shown to the user.
+     *
+     * Use it to setup any background tasks, running expensive setup operations in a background
+     * thread to avoid delaying app start.
+     */
+    override fun onCreate() {
+        super.onCreate()
+        Timber.plant(Timber.DebugTree())
+    }
+}

DevBytesRepository/app/src/main/java/com/example/android/devbyteviewer/database/DatabaseEntities.kt

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+/*
+ * Copyright (C) 2019 Google Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.example.android.devbyteviewer.database
+
+import androidx.room.Entity
+import androidx.room.PrimaryKey
+import com.example.android.devbyteviewer.domain.DevByteVideo
+
+
+/**
+ * Database entities go in this file. These are responsible for reading and writing from the
+ * database.
+ */
+
+
+/**
+ * DatabaseVideo represents a video entity in the database.
+ */
+@Entity
+data class DatabaseVideo constructor(
+        @PrimaryKey
+        val url: String,
+        val updated: String,
+        val title: String,
+        val description: String,
+        val thumbnail: String)
+
+
+/**
+ * Map DatabaseVideos to domain entities
+ */
+fun List<DatabaseVideo>.asDomainModel(): List<DevByteVideo> {
+        return map {
+                DevByteVideo(
+                        url = it.url,
+                        title = it.title,
+                        description = it.description,
+                        updated = it.updated,
+                        thumbnail = it.thumbnail)
+        }
+}

DevBytesRepository/app/src/main/java/com/example/android/devbyteviewer/database/Room.kt

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+/*
+ * Copyright (C) 2019 Google Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.example.android.devbyteviewer.database
+
+import android.content.Context
+import androidx.lifecycle.LiveData
+import androidx.room.*
+
+@Dao
+interface VideoDao {
+    @Query("select * from databasevideo")
+    fun getVideos(): LiveData<List<DatabaseVideo>>
+
+    @Insert(onConflict = OnConflictStrategy.REPLACE)
+    fun insertAll( videos: List<DatabaseVideo>)
+}
+
+
+
+@Database(entities = [DatabaseVideo::class], version = 1)
+abstract class VideosDatabase: RoomDatabase() {
+    abstract val videoDao: VideoDao
+}
+
+private lateinit var INSTANCE: VideosDatabase
+
+fun getDatabase(context: Context): VideosDatabase {
+    synchronized(VideosDatabase::class.java) {
+        if (!::INSTANCE.isInitialized) {
+            INSTANCE = Room.databaseBuilder(context.applicationContext,
+                    VideosDatabase::class.java,
+                    "videos").build()
+        }
+    }
+    return INSTANCE
+}

DevBytesRepository/app/src/main/java/com/example/android/devbyteviewer/domain/Models.kt

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+/*
+ * Copyright (C) 2019 Google Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.example.android.devbyteviewer.domain
+
+import com.example.android.devbyteviewer.util.smartTruncate
+
+/**
+ * Domain objects are plain Kotlin data classes that represent the things in our app. These are the
+ * objects that should be displayed on screen, or manipulated by the app.
+ *
+ * @see database for objects that are mapped to the database
+ * @see network for objects that parse or prepare network calls
+ */
+
+/**
+ * Videos represent a devbyte that can be played.
+ */
+data class DevByteVideo(val title: String,
+                        val description: String,
+                        val url: String,
+                        val updated: String,
+                        val thumbnail: String) {
+
+    /**
+     * Short description is used for displaying truncated descriptions in the UI
+     */
+    val shortDescription: String
+        get() = description.smartTruncate(200)
+}

DevBytesRepository/app/src/main/java/com/example/android/devbyteviewer/network/DataTransferObjects.kt

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+/*
+ * Copyright (C) 2019 Google Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.example.android.devbyteviewer.network
+
+import com.example.android.devbyteviewer.database.DatabaseVideo
+import com.example.android.devbyteviewer.domain.DevByteVideo
+import com.squareup.moshi.JsonClass
+
+/**
+ * DataTransferObjects go in this file. These are responsible for parsing responses from the server
+ * or formatting objects to send to the server. You should convert these to domain objects before
+ * using them.
+ *
+ * @see domain package for
+ */
+
+/**
+ * VideoHolder holds a list of Videos.
+ *
+ * This is to parse first level of our network result which looks like
+ *
+ * {
+ *   "videos": []
+ * }
+ */
+@JsonClass(generateAdapter = true)
+data class NetworkVideoContainer(val videos: List<NetworkVideo>)
+
+/**
+ * Videos represent a devbyte that can be played.
+ */
+@JsonClass(generateAdapter = true)
+data class NetworkVideo(
+        val title: String,
+        val description: String,
+        val url: String,
+        val updated: String,
+        val thumbnail: String,
+        val closedCaptions: String?)
+
+/**
+ * Convert Network results to database objects
+ */
+fun NetworkVideoContainer.asDomainModel(): List<DevByteVideo> {
+    return videos.map {
+        DevByteVideo(
+                title = it.title,
+                description = it.description,
+                url = it.url,
+                updated = it.updated,
+                thumbnail = it.thumbnail)
+    }
+}
+
+
+/**
+ * Convert Network results to database objects
+ */
+fun NetworkVideoContainer.asDatabaseModel(): List<DatabaseVideo> {
+    return videos.map {
+        DatabaseVideo(
+                title = it.title,
+                description = it.description,
+                url = it.url,
+                updated = it.updated,
+                thumbnail = it.thumbnail)
+    }
+}
+

DevBytesRepository/app/src/main/java/com/example/android/devbyteviewer/network/Service.kt

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+/*
+ * Copyright (C) 2019 Google Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.example.android.devbyteviewer.network
+
+import com.jakewharton.retrofit2.adapter.kotlin.coroutines.CoroutineCallAdapterFactory
+import kotlinx.coroutines.Deferred
+import retrofit2.Retrofit
+import retrofit2.converter.moshi.MoshiConverterFactory
+import retrofit2.http.GET
+
+// Since we only have one service, this can all go in one file.
+// If you add more services, split this to multiple files and make sure to share the retrofit
+// object between services.
+
+/**
+ * A retrofit service to fetch a devbyte playlist.
+ */
+interface DevbyteService {
+    @GET("devbytes")
+    fun getPlaylist(): Deferred<NetworkVideoContainer>
+}
+
+/**
+ * Main entry point for network access. Call like `DevByteNetwork.devbytes.getPlaylist()`
+ */
+object DevByteNetwork {
+
+    // Configure retrofit to parse JSON and use coroutines
+    private val retrofit = Retrofit.Builder()
+            .baseUrl("https://android-kotlin-fun-mars-server.appspot.com/")
+            .addConverterFactory(MoshiConverterFactory.create())
+            .addCallAdapterFactory(CoroutineCallAdapterFactory())
+            .build()
+
+    val devbytes = retrofit.create(DevbyteService::class.java)
+
+}
+
+

DevBytesRepository/app/src/main/java/com/example/android/devbyteviewer/repository/VideosRepository.kt

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+/*
+ * Copyright (C) 2019 Google Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.example.android.devbyteviewer.repository
+
+import androidx.lifecycle.LiveData
+import androidx.lifecycle.Transformations
+import com.example.android.devbyteviewer.database.VideosDatabase
+import com.example.android.devbyteviewer.database.asDomainModel
+import com.example.android.devbyteviewer.domain.DevByteVideo
+import com.example.android.devbyteviewer.network.DevByteNetwork
+import com.example.android.devbyteviewer.network.asDatabaseModel
+import kotlinx.coroutines.Dispatchers
+import kotlinx.coroutines.withContext
+import timber.log.Timber
+
+/**
+ * Repository for fetching devbyte videos from the network and storing them on disk
+ */
+class VideosRepository(private val database: VideosDatabase) {
+
+    val videos: LiveData<List<DevByteVideo>> = Transformations.map(database.videoDao.getVideos()) {
+        it.asDomainModel()
+    }
+
+    /**
+     * Refresh the videos stored in the offline cache.
+     *
+     * This function uses the IO dispatcher to ensure the database insert database operation
+     * happens on the IO dispatcher. By switching to the IO dispatcher using `withContext` this
+     * function is now safe to call from any thread including the Main thread.
+     *
+     */
+    suspend fun refreshVideos() {
+        withContext(Dispatchers.IO) {
+            Timber.d("refresh videos is called");
+            val playlist = DevByteNetwork.devbytes.getPlaylist().await()
+            database.videoDao.insertAll(playlist.asDatabaseModel())
+        }
+    }
+
+}

DevBytesRepository/app/src/main/java/com/example/android/devbyteviewer/ui/DevByteActivity.kt

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+/*
+ * Copyright (C) 2019 Google Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.example.android.devbyteviewer.ui
+
+import android.os.Bundle
+import androidx.appcompat.app.AppCompatActivity
+import com.example.android.devbyteviewer.R
+
+/**
+ * This is a single activity application that uses the Navigation library. Content is displayed
+ * by Fragments.
+ */
+class DevByteActivity : AppCompatActivity() {
+
+    /**
+     * Called when the activity is starting.  This is where most initialization
+     * should go
+     */
+    override fun onCreate(savedInstanceState: Bundle?) {
+        super.onCreate(savedInstanceState)
+        setContentView(R.layout.activity_dev_byte_viewer)
+    }
+}

DevBytesRepository/app/src/main/java/com/example/android/devbyteviewer/ui/DevByteFragment.kt

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+/*
+ * Copyright (C) 2019 Google Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.example.android.devbyteviewer.ui
+
+import android.content.Intent
+import android.net.Uri
+import android.os.Bundle
+import android.view.LayoutInflater
+import android.view.View
+import android.view.ViewGroup
+import android.widget.Toast
+import androidx.annotation.LayoutRes
+import androidx.databinding.DataBindingUtil
+import androidx.fragment.app.Fragment
+import androidx.lifecycle.Observer
+import androidx.lifecycle.ViewModelProviders
+import androidx.recyclerview.widget.LinearLayoutManager
+import androidx.recyclerview.widget.RecyclerView
+import com.example.android.devbyteviewer.R
+import com.example.android.devbyteviewer.databinding.DevbyteItemBinding
+import com.example.android.devbyteviewer.databinding.FragmentDevByteBinding
+import com.example.android.devbyteviewer.domain.DevByteVideo
+import com.example.android.devbyteviewer.viewmodels.DevByteViewModel
+
+/**
+ * Show a list of DevBytes on screen.
+ */
+class DevByteFragment : Fragment() {
+
+    /**
+     * One way to delay creation of the viewModel until an appropriate lifecycle method is to use
+     * lazy. This requires that viewModel not be referenced before onActivityCreated, which we
+     * do in this Fragment.
+     */
+    private val viewModel: DevByteViewModel by lazy {
+        val activity = requireNotNull(this.activity) {
+            "You can only access the viewModel after onActivityCreated()"
+        }
+        ViewModelProviders.of(this, DevByteViewModel.Factory(activity.application))
+                .get(DevByteViewModel::class.java)
+    }
+
+    /**
+     * RecyclerView Adapter for converting a list of Video to cards.
+     */
+    private var viewModelAdapter: DevByteAdapter? = null
+
+    /**
+     * Called when the fragment's activity has been created and this
+     * fragment's view hierarchy instantiated.  It can be used to do final
+     * initialization once these pieces are in place, such as retrieving
+     * views or restoring state.
+     */
+    override fun onActivityCreated(savedInstanceState: Bundle?) {
+        super.onActivityCreated(savedInstanceState)
+        viewModel.playlist.observe(viewLifecycleOwner, Observer<List<DevByteVideo>> { videos ->
+            videos?.apply {
+                viewModelAdapter?.videos = videos
+            }
+        })
+    }
+
+    /**
+     * Called to have the fragment instantiate its user interface view.
+     *
+     * <p>If you return a View from here, you will later be called in
+     * {@link #onDestroyView} when the view is being released.
+     *
+     * @param inflater The LayoutInflater object that can be used to inflate
+     * any views in the fragment,
+     * @param container If non-null, this is the parent view that the fragment's
+     * UI should be attached to.  The fragment should not add the view itself,
+     * but this can be used to generate the LayoutParams of the view.
+     * @param savedInstanceState If non-null, this fragment is being re-constructed
+     * from a previous saved state as given here.
+     *
+     * @return Return the View for the fragment's UI.
+     */
+    override fun onCreateView(inflater: LayoutInflater, container: ViewGroup?,
+                              savedInstanceState: Bundle?): View? {
+        val binding: FragmentDevByteBinding = DataBindingUtil.inflate(
+                inflater,
+                R.layout.fragment_dev_byte,
+                container,
+                false)
+        // Set the lifecycleOwner so DataBinding can observe LiveData
+        binding.setLifecycleOwner(viewLifecycleOwner)
+
+        binding.viewModel = viewModel
+
+        viewModelAdapter = DevByteAdapter(VideoClick {
+            // When a video is clicked this block or lambda will be called by DevByteAdapter
+
+            // context is not around, we can safely discard this click since the Fragment is no
+            // longer on the screen
+            val packageManager = context?.packageManager ?: return@VideoClick
+
+            // Try to generate a direct intent to the YouTube app
+            var intent = Intent(Intent.ACTION_VIEW, it.launchUri)
+            if(intent.resolveActivity(packageManager) == null) {
+                // YouTube app isn't found, use the web url
+                intent = Intent(Intent.ACTION_VIEW, Uri.parse(it.url))
+            }
+
+            startActivity(intent)
+        })
+
+        binding.root.findViewById<RecyclerView>(R.id.recycler_view).apply {
+            layoutManager = LinearLayoutManager(context)
+            adapter = viewModelAdapter
+        }
+
+
+        // Observer for the network error.
+        viewModel.eventNetworkError.observe(this, Observer<Boolean> { isNetworkError ->
+            if (isNetworkError) onNetworkError()
+        })
+
+        return binding.root
+    }
+
+    /**
+     * Method for displaying a Toast error message for network errors.
+     */
+    private fun onNetworkError() {
+        if(!viewModel.isNetworkErrorShown.value!!) {
+            Toast.makeText(activity, "Network Error", Toast.LENGTH_LONG).show()
+            viewModel.onNetworkErrorShown()
+        }
+    }
+
+    /**
+     * Helper method to generate YouTube app links
+     */
+    private val DevByteVideo.launchUri: Uri
+        get() {
+            val httpUri = Uri.parse(url)
+            return Uri.parse("vnd.youtube:" + httpUri.getQueryParameter("v"))
+        }
+}
+
+/**
+ * Click listener for Videos. By giving the block a name it helps a reader understand what it does.
+ *
+ */
+class VideoClick(val block: (DevByteVideo) -> Unit) {
+    /**
+     * Called when a video is clicked
+     *
+     * @param video the video that was clicked
+     */
+    fun onClick(video: DevByteVideo) = block(video)
+}
+
+/**
+ * RecyclerView Adapter for setting up data binding on the items in the list.
+ */
+class DevByteAdapter(val callback: VideoClick) : RecyclerView.Adapter<DevByteViewHolder>() {
+
+    /**
+     * The videos that our Adapter will show
+     */
+    var videos: List<DevByteVideo> = emptyList()
+        set(value) {
+            field = value
+            // For an extra challenge, update this to use the paging library.
+
+            // Notify any registered observers that the data set has changed. This will cause every
+            // element in our RecyclerView to be invalidated.
+            notifyDataSetChanged()
+        }
+
+    /**
+     * Called when RecyclerView needs a new {@link ViewHolder} of the given type to represent
+     * an item.
+     */
+    override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): DevByteViewHolder {
+        val withDataBinding: DevbyteItemBinding = DataBindingUtil.inflate(
+                LayoutInflater.from(parent.context),
+                DevByteViewHolder.LAYOUT,
+                parent,
+                false)
+        return DevByteViewHolder(withDataBinding)
+    }
+
+    override fun getItemCount() = videos.size
+
+    /**
+     * Called by RecyclerView to display the data at the specified position. This method should
+     * update the contents of the {@link ViewHolder#itemView} to reflect the item at the given
+     * position.
+     */
+    override fun onBindViewHolder(holder: DevByteViewHolder, position: Int) {
+        holder.viewDataBinding.also {
+            it.video = videos[position]
+            it.videoCallback = callback
+        }
+    }
+
+}
+
+/**
+ * ViewHolder for DevByte items. All work is done by data binding.
+ */
+class DevByteViewHolder(val viewDataBinding: DevbyteItemBinding) :
+        RecyclerView.ViewHolder(viewDataBinding.root) {
+    companion object {
+        @LayoutRes
+        val LAYOUT = R.layout.devbyte_item
+    }
+}

DevBytesRepository/app/src/main/java/com/example/android/devbyteviewer/util/BindingAdapters.kt

@@ -0,0 +1,42 @@
+/*
+ * Copyright (C) 2019 Google Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.example.android.devbyteviewer.util
+
+import android.view.View
+import android.widget.ImageView
+import androidx.databinding.BindingAdapter
+import com.bumptech.glide.Glide
+
+/**
+ * Binding adapter used to hide the spinner once data is available.
+ */
+@BindingAdapter("isNetworkError", "playlist")
+fun hideIfNetworkError(view: View, isNetWorkError: Boolean, playlist: Any?) {
+    view.visibility = if (playlist != null) View.GONE else View.VISIBLE
+
+    if(isNetWorkError) {
+        view.visibility = View.GONE
+    }
+}
+
+/**
+ * Binding adapter used to display images from URL using Glide
+ */
+@BindingAdapter("imageUrl")
+fun setImageUrl(imageView: ImageView, url: String) {
+    Glide.with(imageView.context).load(url).into(imageView)
+}

DevBytesRepository/app/src/main/java/com/example/android/devbyteviewer/util/Util.kt

@@ -0,0 +1,49 @@
+/*
+ * Copyright (C) 2019 Google Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.example.android.devbyteviewer.util
+
+private val PUNCTUATION = listOf(", ", "; ", ": ", " ")
+
+/**
+ * Truncate long text with a preference for word boundaries and without trailing punctuation.
+ */
+fun String.smartTruncate(length: Int): String {
+    val words = split(" ")
+    var added = 0
+    var hasMore = false
+    val builder = StringBuilder()
+    for (word in words) {
+        if (builder.length > length) {
+            hasMore = true
+            break
+        }
+        builder.append(word)
+        builder.append(" ")
+        added += 1
+    }
+
+    PUNCTUATION.map {
+        if (builder.endsWith(it)) {
+            builder.replace(builder.length - it.length, builder.length, "")
+        }
+    }
+
+    if (hasMore) {
+        builder.append("...")
+    }
+    return builder.toString()
+}

DevBytesRepository/app/src/main/java/com/example/android/devbyteviewer/viewmodels/DevByteViewModel.kt

@@ -0,0 +1,152 @@
+/*
+ * Copyright (C) 2019 Google Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.example.android.devbyteviewer.viewmodels
+
+import android.app.Application
+import androidx.lifecycle.AndroidViewModel
+import androidx.lifecycle.LiveData
+import androidx.lifecycle.MutableLiveData
+import androidx.lifecycle.ViewModel
+import androidx.lifecycle.ViewModelProvider
+import com.example.android.devbyteviewer.database.getDatabase
+import com.example.android.devbyteviewer.domain.DevByteVideo
+import com.example.android.devbyteviewer.network.DevByteNetwork
+import com.example.android.devbyteviewer.network.asDomainModel
+import com.example.android.devbyteviewer.repository.VideosRepository
+import kotlinx.coroutines.*
+import java.io.IOException
+
+/**
+ * DevByteViewModel designed to store and manage UI-related data in a lifecycle conscious way. This
+ * allows data to survive configuration changes such as screen rotations. In addition, background
+ * work such as fetching network results can continue through configuration changes and deliver
+ * results after the new Fragment or Activity is available.
+ *
+ * @param application The application that this viewmodel is attached to, it's safe to hold a
+ * reference to applications across rotation since Application is never recreated during actiivty
+ * or fragment lifecycle events.
+ */
+class DevByteViewModel(application: Application) : AndroidViewModel(application) {
+
+
+    /**
+     * The data source this ViewModel will fetch results from.
+     */
+    private val videosRepository = VideosRepository(getDatabase(application))
+
+    /**
+     * A playlist of videos displayed on the screen.
+     */
+    val playlist = videosRepository.videos
+
+    /**
+     * This is the job for all coroutines started by this ViewModel.
+     *
+     * Cancelling this job will cancel all coroutines started by this ViewModel.
+     */
+    private val viewModelJob = SupervisorJob()
+
+    /**
+     * This is the main scope for all coroutines launched by MainViewModel.
+     *
+     * Since we pass viewModelJob, you can cancel all coroutines launched by uiScope by calling
+     * viewModelJob.cancel()
+     */
+    private val viewModelScope = CoroutineScope(viewModelJob + Dispatchers.Main)
+
+    /**
+     * Event triggered for network error. This is private to avoid exposing a
+     * way to set this value to observers.
+     */
+    private var _eventNetworkError = MutableLiveData<Boolean>(false)
+
+    /**
+     * Event triggered for network error. Views should use this to get access
+     * to the data.
+     */
+    val eventNetworkError: LiveData<Boolean>
+        get() = _eventNetworkError
+
+    /**
+     * Flag to display the error message. This is private to avoid exposing a
+     * way to set this value to observers.
+     */
+    private var _isNetworkErrorShown = MutableLiveData<Boolean>(false)
+
+    /**
+     * Flag to display the error message. Views should use this to get access
+     * to the data.
+     */
+    val isNetworkErrorShown: LiveData<Boolean>
+        get() = _isNetworkErrorShown
+
+    /**
+     * init{} is called immediately when this ViewModel is created.
+     */
+    init {
+        refreshDataFromRepository()
+    }
+
+    /**
+     * Refresh data from the repository. Use a coroutine launch to run in a
+     * background thread.
+     */
+    private fun refreshDataFromRepository() {
+        viewModelScope.launch {
+            try {
+                videosRepository.refreshVideos()
+                _eventNetworkError.value = false
+                _isNetworkErrorShown.value = false
+
+            } catch (networkError: IOException) {
+                // Show a Toast error message and hide the progress bar.
+                if(playlist.value!!.isEmpty())
+                    _eventNetworkError.value = true
+            }
+        }
+    }
+
+
+    /**
+     * Resets the network error flag.
+     */
+    fun onNetworkErrorShown() {
+        _isNetworkErrorShown.value = true
+    }
+
+
+    /**
+     * Cancel all coroutines when the ViewModel is cleared
+     */
+    override fun onCleared() {
+        super.onCleared()
+        viewModelJob.cancel()
+    }
+
+    /**
+     * Factory for constructing DevByteViewModel with parameter
+     */
+    class Factory(val app: Application) : ViewModelProvider.Factory {
+        override fun <T : ViewModel?> create(modelClass: Class<T>): T {
+            if (modelClass.isAssignableFrom(DevByteViewModel::class.java)) {
+                @Suppress("UNCHECKED_CAST")
+                return DevByteViewModel(app) as T
+            }
+            throw IllegalArgumentException("Unable to construct viewmodel")
+        }
+    }
+}

DevBytesRepository/app/src/main/res/drawable-v24/ic_launcher_foreground.xml

@@ -0,0 +1,50 @@
+<!--
+  ~ Copyright (C) 2019 Google Inc.
+  ~
+  ~ Licensed under the Apache License, Version 2.0 (the "License");
+  ~ you may not use this file except in compliance with the License.
+  ~ You may obtain a copy of the License at
+  ~
+  ~     http://www.apache.org/licenses/LICENSE-2.0
+  ~
+  ~ Unless required by applicable law or agreed to in writing, software
+  ~ distributed under the License is distributed on an "AS IS" BASIS,
+  ~ WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+  ~ See the License for the specific language governing permissions and
+  ~ limitations under the License.
+  -->
+
+<vector xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:aapt="http://schemas.android.com/aapt"
+    android:width="108dp"
+    android:height="108dp"
+    android:viewportWidth="108"
+    android:viewportHeight="108">
+    <path
+        android:fillType="evenOdd"
+        android:pathData="M32,64C32,64 38.39,52.99 44.13,50.95C51.37,48.37 70.14,49.57 70.14,49.57L108.26,87.69L108,109.01L75.97,107.97L32,64Z"
+        android:strokeWidth="1"
+        android:strokeColor="#00000000">
+        <aapt:attr name="android:fillColor">
+            <gradient
+                android:endX="78.5885"
+                android:endY="90.9159"
+                android:startX="48.7653"
+                android:startY="61.0927"
+                android:type="linear">
+                <item
+                    android:color="#44000000"
+                    android:offset="0.0" />
+                <item
+                    android:color="#00000000"
+                    android:offset="1.0" />
+            </gradient>
+        </aapt:attr>
+    </path>
+    <path
+        android:fillColor="#FFFFFF"
+        android:fillType="nonZero"
+        android:pathData="M66.94,46.02L66.94,46.02C72.44,50.07 76,56.61 76,64L32,64C32,56.61 35.56,50.11 40.98,46.06L36.18,41.19C35.45,40.45 35.45,39.3 36.18,38.56C36.91,37.81 38.05,37.81 38.78,38.56L44.25,44.05C47.18,42.57 50.48,41.71 54,41.71C57.48,41.71 60.78,42.57 63.68,44.05L69.11,38.56C69.84,37.81 70.98,37.81 71.71,38.56C72.44,39.3 72.44,40.45 71.71,41.19L66.94,46.02ZM62.94,56.92C64.08,56.92 65,56.01 65,54.88C65,53.76 64.08,52.85 62.94,52.85C61.8,52.85 60.88,53.76 60.88,54.88C60.88,56.01 61.8,56.92 62.94,56.92ZM45.06,56.92C46.2,56.92 47.13,56.01 47.13,54.88C47.13,53.76 46.2,52.85 45.06,52.85C43.92,52.85 43,53.76 43,54.88C43,56.01 43.92,56.92 45.06,56.92Z"
+        android:strokeWidth="1"
+        android:strokeColor="#00000000" />
+</vector>

DevBytesRepository/app/src/main/res/drawable/ic_launcher_background.xml

@@ -0,0 +1,186 @@
+<?xml version="1.0" encoding="utf-8"?>
+<!--
+  ~ Copyright (C) 2019 Google Inc.
+  ~
+  ~ Licensed under the Apache License, Version 2.0 (the "License");
+  ~ you may not use this file except in compliance with the License.
+  ~ You may obtain a copy of the License at
+  ~
+  ~     http://www.apache.org/licenses/LICENSE-2.0
+  ~
+  ~ Unless required by applicable law or agreed to in writing, software
+  ~ distributed under the License is distributed on an "AS IS" BASIS,
+  ~ WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+  ~ See the License for the specific language governing permissions and
+  ~ limitations under the License.
+  -->
+
+<vector xmlns:android="http://schemas.android.com/apk/res/android"
+    android:width="108dp"
+    android:height="108dp"
+    android:viewportWidth="108"
+    android:viewportHeight="108">
+    <path
+        android:fillColor="#008577"
+        android:pathData="M0,0h108v108h-108z" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M9,0L9,108"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M19,0L19,108"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M29,0L29,108"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M39,0L39,108"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M49,0L49,108"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M59,0L59,108"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M69,0L69,108"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M79,0L79,108"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M89,0L89,108"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M99,0L99,108"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M0,9L108,9"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M0,19L108,19"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M0,29L108,29"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M0,39L108,39"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M0,49L108,49"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M0,59L108,59"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M0,69L108,69"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M0,79L108,79"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M0,89L108,89"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M0,99L108,99"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M19,29L89,29"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M19,39L89,39"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M19,49L89,49"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M19,59L89,59"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M19,69L89,69"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M19,79L89,79"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M29,19L29,89"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M39,19L39,89"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M49,19L49,89"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M59,19L59,89"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M69,19L69,89"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M79,19L79,89"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+</vector>

DevBytesRepository/app/src/main/res/drawable/ic_play_circle_outline_black_48dp.xml

@@ -0,0 +1,25 @@
+<!--
+  ~ Copyright (C) 2019 Google Inc.
+  ~
+  ~ Licensed under the Apache License, Version 2.0 (the "License");
+  ~ you may not use this file except in compliance with the License.
+  ~ You may obtain a copy of the License at
+  ~
+  ~     http://www.apache.org/licenses/LICENSE-2.0
+  ~
+  ~ Unless required by applicable law or agreed to in writing, software
+  ~ distributed under the License is distributed on an "AS IS" BASIS,
+  ~ WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+  ~ See the License for the specific language governing permissions and
+  ~ limitations under the License.
+  -->
+
+<vector android:height="24dp"
+    android:viewportHeight="48"
+    android:viewportWidth="48"
+    android:width="24dp"
+    xmlns:android="http://schemas.android.com/apk/res/android">
+    <path
+        android:fillColor="#000000"
+        android:pathData="M20,33l12,-9 -12,-9v18zM24,4C12.95,4 4,12.95 4,24s8.95,20 20,20 20,-8.95 20,-20S35.05,4 24,4zM24,40c-8.82,0 -16,-7.18 -16,-16S15.18,8 24,8s16,7.18 16,16 -7.18,16 -16,16z" />
+</vector>

DevBytesRepository/app/src/main/res/layout/activity_dev_byte_viewer.xml

@@ -0,0 +1,33 @@
+<?xml version="1.0" encoding="utf-8"?>
+<!--
+  ~ Copyright (C) 2019 Google Inc.
+  ~
+  ~ Licensed under the Apache License, Version 2.0 (the "License");
+  ~ you may not use this file except in compliance with the License.
+  ~ You may obtain a copy of the License at
+  ~
+  ~     http://www.apache.org/licenses/LICENSE-2.0
+  ~
+  ~ Unless required by applicable law or agreed to in writing, software
+  ~ distributed under the License is distributed on an "AS IS" BASIS,
+  ~ WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+  ~ See the License for the specific language governing permissions and
+  ~ limitations under the License.
+  -->
+
+<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:app="http://schemas.android.com/apk/res-auto"
+    xmlns:tools="http://schemas.android.com/tools"
+    android:layout_width="match_parent"
+    android:layout_height="match_parent"
+    tools:context=".ui.DevByteActivity">
+
+    <fragment
+        android:layout_width="match_parent"
+        android:layout_height="match_parent"
+        android:id="@+id/my_nav_host_fragment"
+        android:name="androidx.navigation.fragment.NavHostFragment"
+        app:navGraph="@navigation/nav_graph"
+        app:defaultNavHost="true" />
+
+</FrameLayout>

DevBytesRepository/app/src/main/res/layout/devbyte_item.xml

@@ -0,0 +1,130 @@
+<?xml version="1.0" encoding="utf-8"?>
+
+<!--
+  ~ Copyright (C) 2019 Google Inc.
+  ~
+  ~ Licensed under the Apache License, Version 2.0 (the "License");
+  ~ you may not use this file except in compliance with the License.
+  ~ You may obtain a copy of the License at
+  ~
+  ~     http://www.apache.org/licenses/LICENSE-2.0
+  ~
+  ~ Unless required by applicable law or agreed to in writing, software
+  ~ distributed under the License is distributed on an "AS IS" BASIS,
+  ~ WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+  ~ See the License for the specific language governing permissions and
+  ~ limitations under the License.
+  -->
+
+<layout xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:app="http://schemas.android.com/apk/res-auto"
+    xmlns:tools="http://schemas.android.com/tools">
+
+    <data>
+
+        <variable
+            name="video"
+            type="com.example.android.devbyteviewer.domain.DevByteVideo" />
+
+        <variable
+            name="videoCallback"
+            type="com.example.android.devbyteviewer.ui.VideoClick" />
+    </data>
+
+    <com.google.android.material.card.MaterialCardView
+        android:layout_width="match_parent"
+        android:layout_height="wrap_content"
+        app:cardCornerRadius="0dp"
+        app:cardElevation="5dp"
+        android:layout_marginTop="8dp"
+        android:layout_marginBottom="16dp">
+
+        <androidx.constraintlayout.widget.ConstraintLayout
+            android:layout_width="match_parent"
+            android:layout_height="wrap_content">
+
+            <androidx.constraintlayout.widget.Guideline
+                android:id="@+id/left_well"
+                android:layout_width="wrap_content"
+                android:layout_height="wrap_content"
+                android:orientation="vertical"
+                app:layout_constraintGuide_begin="8dp" />
+
+            <androidx.constraintlayout.widget.Guideline
+                android:id="@+id/right_well"
+                android:layout_width="wrap_content"
+                android:layout_height="wrap_content"
+                android:layout_marginEnd="8dp"
+                android:orientation="vertical"
+                app:layout_constraintGuide_end="8dp" />
+
+            <ImageView
+                android:id="@+id/play_icon"
+                android:layout_width="wrap_content"
+                android:layout_height="wrap_content"
+                android:layout_marginTop="14dp"
+                app:layout_constraintStart_toStartOf="@+id/left_well"
+                app:layout_constraintTop_toBottomOf="@+id/video_thumbnail"
+                app:srcCompat="@drawable/ic_play_circle_outline_black_48dp" />
+
+            <TextView
+                android:id="@+id/title"
+                android:layout_width="0dp"
+                android:layout_height="wrap_content"
+                android:layout_marginStart="4dp"
+                android:layout_marginTop="16dp"
+                android:text="@{video.title}"
+                android:textAlignment="viewStart"
+                android:textAllCaps="false"
+                android:textColor="@color/text_black"
+                android:textStyle="bold"
+                app:layout_constraintEnd_toStartOf="@+id/right_well"
+                app:layout_constraintStart_toEndOf="@+id/play_icon"
+                app:layout_constraintTop_toBottomOf="@+id/video_thumbnail"
+                tools:text="Video title" />
+
+
+            <TextView
+                android:id="@+id/description"
+                android:layout_width="0dp"
+                android:layout_height="wrap_content"
+                android:layout_marginTop="8dp"
+                android:layout_marginBottom="16dp"
+                android:text="@{video.shortDescription}"
+                android:textAlignment="viewStart"
+                android:textAllCaps="false"
+                android:textColor="@color/text_light"
+                android:textSize="14sp"
+                app:layout_constraintEnd_toEndOf="@+id/right_well"
+                app:layout_constraintStart_toStartOf="@+id/left_well"
+                app:layout_constraintTop_toBottomOf="@+id/title"
+                app:layout_constraintBottom_toBottomOf="parent"
+                tools:text="this is a video @android:string/fingerprint_icon_content_description" />
+
+            <ImageView
+                android:id="@+id/video_thumbnail"
+                android:layout_width="0dp"
+                android:layout_height="0dp"
+                android:adjustViewBounds="false"
+                android:cropToPadding="false"
+                android:scaleType="centerCrop"
+                app:imageUrl="@{video.thumbnail}"
+                app:layout_constraintDimensionRatio="h,4:3"
+                app:layout_constraintEnd_toEndOf="parent"
+                app:layout_constraintStart_toStartOf="parent"
+                app:layout_constraintTop_toTopOf="parent"
+                tools:srcCompat="@tools:sample/backgrounds/scenic" />
+
+            <View
+                android:id="@+id/clickableOverlay"
+                android:layout_width="0dp"
+                android:layout_height="0dp"
+                android:background="?attr/selectableItemBackground"
+                android:onClick="@{() -> videoCallback.onClick(video)}"
+                app:layout_constraintBottom_toBottomOf="parent"
+                app:layout_constraintEnd_toEndOf="parent"
+                app:layout_constraintStart_toStartOf="parent"
+                app:layout_constraintTop_toTopOf="parent" />
+        </androidx.constraintlayout.widget.ConstraintLayout>
+    </com.google.android.material.card.MaterialCardView>
+</layout>

DevBytesRepository/app/src/main/res/layout/fragment_dev_byte.xml

@@ -0,0 +1,53 @@
+<?xml version="1.0" encoding="utf-8"?>
+<!--
+  ~ Copyright (C) 2019 Google Inc.
+  ~
+  ~ Licensed under the Apache License, Version 2.0 (the "License");
+  ~ you may not use this file except in compliance with the License.
+  ~ You may obtain a copy of the License at
+  ~
+  ~     http://www.apache.org/licenses/LICENSE-2.0
+  ~
+  ~ Unless required by applicable law or agreed to in writing, software
+  ~ distributed under the License is distributed on an "AS IS" BASIS,
+  ~ WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+  ~ See the License for the specific language governing permissions and
+  ~ limitations under the License.
+  -->
+
+<layout xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:app="http://schemas.android.com/apk/res-auto"
+    xmlns:tools="http://schemas.android.com/tools"
+    tools:context=".ui.DevByteFragment">
+
+    <data>
+        <variable
+            name="viewModel"
+            type="com.example.android.devbyteviewer.viewmodels.DevByteViewModel" />
+    </data>
+
+    <FrameLayout
+        android:layout_width="match_parent"
+        android:layout_height="match_parent"
+        android:background="@color/background_grey">
+
+        <ProgressBar
+            android:id="@+id/loading_spinner"
+            android:layout_width="wrap_content"
+            android:layout_height="wrap_content"
+            app:isNetworkError = "@{safeUnbox(viewModel.eventNetworkError)}"
+            app:playlist = "@{viewModel.playlist}"
+
+
+
+        android:layout_gravity="center" />
+
+        <androidx.recyclerview.widget.RecyclerView
+            android:id="@+id/recycler_view"
+            android:layout_width="match_parent"
+            android:layout_height="match_parent"
+            tools:listitem="@layout/devbyte_item" />
+    </FrameLayout>
+</layout>
+
+

DevBytesRepository/app/src/main/res/mipmap-anydpi-v26/ic_launcher.xml

@@ -0,0 +1,21 @@
+<?xml version="1.0" encoding="utf-8"?>
+<!--
+  ~ Copyright (C) 2019 Google Inc.
+  ~
+  ~ Licensed under the Apache License, Version 2.0 (the "License");
+  ~ you may not use this file except in compliance with the License.
+  ~ You may obtain a copy of the License at
+  ~
+  ~     http://www.apache.org/licenses/LICENSE-2.0
+  ~
+  ~ Unless required by applicable law or agreed to in writing, software
+  ~ distributed under the License is distributed on an "AS IS" BASIS,
+  ~ WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+  ~ See the License for the specific language governing permissions and
+  ~ limitations under the License.
+  -->
+
+<adaptive-icon xmlns:android="http://schemas.android.com/apk/res/android">
+    <background android:drawable="@drawable/ic_launcher_background" />
+    <foreground android:drawable="@drawable/ic_launcher_foreground" />
+</adaptive-icon>

DevBytesRepository/app/src/main/res/mipmap-anydpi-v26/ic_launcher_round.xml

@@ -0,0 +1,21 @@
+<?xml version="1.0" encoding="utf-8"?>
+<!--
+  ~ Copyright (C) 2019 Google Inc.
+  ~
+  ~ Licensed under the Apache License, Version 2.0 (the "License");
+  ~ you may not use this file except in compliance with the License.
+  ~ You may obtain a copy of the License at
+  ~
+  ~     http://www.apache.org/licenses/LICENSE-2.0
+  ~
+  ~ Unless required by applicable law or agreed to in writing, software
+  ~ distributed under the License is distributed on an "AS IS" BASIS,
+  ~ WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+  ~ See the License for the specific language governing permissions and
+  ~ limitations under the License.
+  -->
+
+<adaptive-icon xmlns:android="http://schemas.android.com/apk/res/android">
+    <background android:drawable="@drawable/ic_launcher_background" />
+    <foreground android:drawable="@drawable/ic_launcher_foreground" />
+</adaptive-icon>

DevBytesRepository/app/src/main/res/navigation/nav_graph.xml

@@ -0,0 +1,29 @@
+<?xml version="1.0" encoding="utf-8"?>
+<!--
+  ~ Copyright (C) 2019 Google Inc.
+  ~
+  ~ Licensed under the Apache License, Version 2.0 (the "License");
+  ~ you may not use this file except in compliance with the License.
+  ~ You may obtain a copy of the License at
+  ~
+  ~     http://www.apache.org/licenses/LICENSE-2.0
+  ~
+  ~ Unless required by applicable law or agreed to in writing, software
+  ~ distributed under the License is distributed on an "AS IS" BASIS,
+  ~ WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+  ~ See the License for the specific language governing permissions and
+  ~ limitations under the License.
+  -->
+
+<navigation xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:app="http://schemas.android.com/apk/res-auto"
+    xmlns:tools="http://schemas.android.com/tools"
+    android:id="@+id/nav_graph"
+    app:startDestination="@id/devByte">
+
+    <fragment
+        android:id="@+id/devByte"
+        android:name="com.example.android.devbyteviewer.ui.DevByteFragment"
+        android:label="fragment_dev_byte"
+        tools:layout="@layout/fragment_dev_byte" />
+</navigation>

DevBytesRepository/app/src/main/res/values/colors.xml

@@ -0,0 +1,26 @@
+<?xml version="1.0" encoding="utf-8"?>
+<!--
+  ~ Copyright (C) 2019 Google Inc.
+  ~
+  ~ Licensed under the Apache License, Version 2.0 (the "License");
+  ~ you may not use this file except in compliance with the License.
+  ~ You may obtain a copy of the License at
+  ~
+  ~     http://www.apache.org/licenses/LICENSE-2.0
+  ~
+  ~ Unless required by applicable law or agreed to in writing, software
+  ~ distributed under the License is distributed on an "AS IS" BASIS,
+  ~ WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+  ~ See the License for the specific language governing permissions and
+  ~ limitations under the License.
+  -->
+
+<resources>
+    <color name="colorPrimary">#1E8E3E</color>
+    <color name="colorPrimaryDark">#0D652D</color>
+    <color name="colorAccent">#E37400</color>
+
+    <color name="background_grey">#ffDDDDDD</color>
+    <color name="text_light">#ff666666</color>
+    <color name="text_black">#ff222222</color>
+</resources>

DevBytesRepository/app/src/main/res/values/strings.xml

@@ -0,0 +1,19 @@
+<!--
+  ~ Copyright (C) 2019 Google Inc.
+  ~
+  ~ Licensed under the Apache License, Version 2.0 (the "License");
+  ~ you may not use this file except in compliance with the License.
+  ~ You may obtain a copy of the License at
+  ~
+  ~     http://www.apache.org/licenses/LICENSE-2.0
+  ~
+  ~ Unless required by applicable law or agreed to in writing, software
+  ~ distributed under the License is distributed on an "AS IS" BASIS,
+  ~ WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+  ~ See the License for the specific language governing permissions and
+  ~ limitations under the License.
+  -->
+
+<resources>
+    <string name="app_name">DevByte Viewer</string>
+</resources>

DevBytesRepository/app/src/main/res/values/styles.xml

@@ -0,0 +1,27 @@
+<!--
+  ~ Copyright (C) 2019 Google Inc.
+  ~
+  ~ Licensed under the Apache License, Version 2.0 (the "License");
+  ~ you may not use this file except in compliance with the License.
+  ~ You may obtain a copy of the License at
+  ~
+  ~     http://www.apache.org/licenses/LICENSE-2.0
+  ~
+  ~ Unless required by applicable law or agreed to in writing, software
+  ~ distributed under the License is distributed on an "AS IS" BASIS,
+  ~ WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+  ~ See the License for the specific language governing permissions and
+  ~ limitations under the License.
+  -->
+
+<resources>
+
+    <!-- Base application theme. -->
+    <style name="AppTheme" parent="Theme.AppCompat.Light.DarkActionBar">
+        <!-- Customize your theme here. -->
+        <item name="colorPrimary">@color/colorPrimary</item>
+        <item name="colorPrimaryDark">@color/colorPrimaryDark</item>
+        <item name="colorAccent">@color/colorAccent</item>
+    </style>
+
+</resources>

DevBytesRepository/build.gradle

@@ -0,0 +1,45 @@
+/*
+ * Copyright (C) 2019 Google Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+// Top-level build file where you can add configuration options common to all sub-projects/modules.
+
+buildscript {
+    ext.kotlin_version = '1.3.31'
+    repositories {
+        google()
+        jcenter()
+    }
+    dependencies {
+        classpath 'com.android.tools.build:gradle:3.4.0'
+        classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:$kotlin_version"
+        classpath "android.arch.navigation:navigation-safe-args-gradle-plugin:1.0.0"
+
+        // NOTE: Do not place your application dependencies here; they belong
+        // in the individual module build.gradle files
+    }
+}
+
+allprojects {
+    repositories {
+        google()
+        jcenter()
+        maven { url "https://kotlin.bintray.com/kotlinx/" }
+    }
+}
+
+task clean(type: Delete) {
+    delete rootProject.buildDir
+}

DevBytesRepository/gradle.properties

@@ -0,0 +1,31 @@
+#
+# Copyright (C) 2019 Google Inc.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+#
+
+# Project-wide Gradle settings.
+# IDE (e.g. Android Studio) users:
+# Gradle settings configured through the IDE *will override*
+# any settings specified in this file.
+# For more details on how to configure your build environment visit
+# http://www.gradle.org/docs/current/userguide/build_environment.html
+# Specifies the JVM arguments used for the daemon process.
+# The setting is particularly useful for tweaking memory settings.
+android.enableJetifier=true
+android.useAndroidX=true
+org.gradle.jvmargs=-Xmx1536m
+# When configured, Gradle will run in incubating parallel mode.
+# This option should only be used with decoupled projects. More details, visit
+# http://www.gradle.org/docs/current/userguide/multi_project_builds.html#sec:decoupled_projects
+# org.gradle.parallel=true

DevBytesRepository/gradle/wrapper/gradle-wrapper.properties

@@ -0,0 +1,6 @@
+#Thu Apr 25 13:35:31 PDT 2019
+distributionBase=GRADLE_USER_HOME
+distributionPath=wrapper/dists
+zipStoreBase=GRADLE_USER_HOME
+zipStorePath=wrapper/dists
+distributionUrl=https\://services.gradle.org/distributions/gradle-5.1.1-all.zip

DevBytesRepository/gradlew

@@ -0,0 +1,172 @@
+#!/usr/bin/env sh
+
+##############################################################################
+##
+##  Gradle start up script for UN*X
+##
+##############################################################################
+
+# Attempt to set APP_HOME
+# Resolve links: $0 may be a link
+PRG="$0"
+# Need this for relative symlinks.
+while [ -h "$PRG" ] ; do
+    ls=`ls -ld "$PRG"`
+    link=`expr "$ls" : '.*-> \(.*\)$'`
+    if expr "$link" : '/.*' > /dev/null; then
+        PRG="$link"
+    else
+        PRG=`dirname "$PRG"`"/$link"
+    fi
+done
+SAVED="`pwd`"
+cd "`dirname \"$PRG\"`/" >/dev/null
+APP_HOME="`pwd -P`"
+cd "$SAVED" >/dev/null
+
+APP_NAME="Gradle"
+APP_BASE_NAME=`basename "$0"`
+
+# Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
+DEFAULT_JVM_OPTS=""
+
+# Use the maximum available, or set MAX_FD != -1 to use that value.
+MAX_FD="maximum"
+
+warn () {
+    echo "$*"
+}
+
+die () {
+    echo
+    echo "$*"
+    echo
+    exit 1
+}
+
+# OS specific support (must be 'true' or 'false').
+cygwin=false
+msys=false
+darwin=false
+nonstop=false
+case "`uname`" in
+  CYGWIN* )
+    cygwin=true
+    ;;
+  Darwin* )
+    darwin=true
+    ;;
+  MINGW* )
+    msys=true
+    ;;
+  NONSTOP* )
+    nonstop=true
+    ;;
+esac
+
+CLASSPATH=$APP_HOME/gradle/wrapper/gradle-wrapper.jar
+
+# Determine the Java command to use to start the JVM.
+if [ -n "$JAVA_HOME" ] ; then
+    if [ -x "$JAVA_HOME/jre/sh/java" ] ; then
+        # IBM's JDK on AIX uses strange locations for the executables
+        JAVACMD="$JAVA_HOME/jre/sh/java"
+    else
+        JAVACMD="$JAVA_HOME/bin/java"
+    fi
+    if [ ! -x "$JAVACMD" ] ; then
+        die "ERROR: JAVA_HOME is set to an invalid directory: $JAVA_HOME
+
+Please set the JAVA_HOME variable in your environment to match the
+location of your Java installation."
+    fi
+else
+    JAVACMD="java"
+    which java >/dev/null 2>&1 || die "ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+
+Please set the JAVA_HOME variable in your environment to match the
+location of your Java installation."
+fi
+
+# Increase the maximum file descriptors if we can.
+if [ "$cygwin" = "false" -a "$darwin" = "false" -a "$nonstop" = "false" ] ; then
+    MAX_FD_LIMIT=`ulimit -H -n`
+    if [ $? -eq 0 ] ; then
+        if [ "$MAX_FD" = "maximum" -o "$MAX_FD" = "max" ] ; then
+            MAX_FD="$MAX_FD_LIMIT"
+        fi
+        ulimit -n $MAX_FD
+        if [ $? -ne 0 ] ; then
+            warn "Could not set maximum file descriptor limit: $MAX_FD"
+        fi
+    else
+        warn "Could not query maximum file descriptor limit: $MAX_FD_LIMIT"
+    fi
+fi
+
+# For Darwin, add options to specify how the application appears in the dock
+if $darwin; then
+    GRADLE_OPTS="$GRADLE_OPTS \"-Xdock:name=$APP_NAME\" \"-Xdock:icon=$APP_HOME/media/gradle.icns\""
+fi
+
+# For Cygwin, switch paths to Windows format before running java
+if $cygwin ; then
+    APP_HOME=`cygpath --path --mixed "$APP_HOME"`
+    CLASSPATH=`cygpath --path --mixed "$CLASSPATH"`
+    JAVACMD=`cygpath --unix "$JAVACMD"`
+
+    # We build the pattern for arguments to be converted via cygpath
+    ROOTDIRSRAW=`find -L / -maxdepth 1 -mindepth 1 -type d 2>/dev/null`
+    SEP=""
+    for dir in $ROOTDIRSRAW ; do
+        ROOTDIRS="$ROOTDIRS$SEP$dir"
+        SEP="|"
+    done
+    OURCYGPATTERN="(^($ROOTDIRS))"
+    # Add a user-defined pattern to the cygpath arguments
+    if [ "$GRADLE_CYGPATTERN" != "" ] ; then
+        OURCYGPATTERN="$OURCYGPATTERN|($GRADLE_CYGPATTERN)"
+    fi
+    # Now convert the arguments - kludge to limit ourselves to /bin/sh
+    i=0
+    for arg in "$@" ; do
+        CHECK=`echo "$arg"|egrep -c "$OURCYGPATTERN" -`
+        CHECK2=`echo "$arg"|egrep -c "^-"`                                 ### Determine if an option
+
+        if [ $CHECK -ne 0 ] && [ $CHECK2 -eq 0 ] ; then                    ### Added a condition
+            eval `echo args$i`=`cygpath --path --ignore --mixed "$arg"`
+        else
+            eval `echo args$i`="\"$arg\""
+        fi
+        i=$((i+1))
+    done
+    case $i in
+        (0) set -- ;;
+        (1) set -- "$args0" ;;
+        (2) set -- "$args0" "$args1" ;;
+        (3) set -- "$args0" "$args1" "$args2" ;;
+        (4) set -- "$args0" "$args1" "$args2" "$args3" ;;
+        (5) set -- "$args0" "$args1" "$args2" "$args3" "$args4" ;;
+        (6) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" ;;
+        (7) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" "$args6" ;;
+        (8) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" "$args6" "$args7" ;;
+        (9) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" "$args6" "$args7" "$args8" ;;
+    esac
+fi
+
+# Escape application args
+save () {
+    for i do printf %s\\n "$i" | sed "s/'/'\\\\''/g;1s/^/'/;\$s/\$/' \\\\/" ; done
+    echo " "
+}
+APP_ARGS=$(save "$@")
+
+# Collect all arguments for the java command, following the shell quoting and substitution rules
+eval set -- $DEFAULT_JVM_OPTS $JAVA_OPTS $GRADLE_OPTS "\"-Dorg.gradle.appname=$APP_BASE_NAME\"" -classpath "\"$CLASSPATH\"" org.gradle.wrapper.GradleWrapperMain "$APP_ARGS"
+
+# by default we should be in the correct project dir, but when run from Finder on Mac, the cwd is wrong
+if [ "$(uname)" = "Darwin" ] && [ "$HOME" = "$PWD" ]; then
+  cd "$(dirname "$0")"
+fi
+
+exec "$JAVACMD" "$@"

DevBytesRepository/gradlew.bat

@@ -0,0 +1,84 @@
+@if "%DEBUG%" == "" @echo off
+@rem ##########################################################################
+@rem
+@rem  Gradle startup script for Windows
+@rem
+@rem ##########################################################################
+
+@rem Set local scope for the variables with windows NT shell
+if "%OS%"=="Windows_NT" setlocal
+
+set DIRNAME=%~dp0
+if "%DIRNAME%" == "" set DIRNAME=.
+set APP_BASE_NAME=%~n0
+set APP_HOME=%DIRNAME%
+
+@rem Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
+set DEFAULT_JVM_OPTS=
+
+@rem Find java.exe
+if defined JAVA_HOME goto findJavaFromJavaHome
+
+set JAVA_EXE=java.exe
+%JAVA_EXE% -version >NUL 2>&1
+if "%ERRORLEVEL%" == "0" goto init
+
+echo.
+echo ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+echo.
+echo Please set the JAVA_HOME variable in your environment to match the
+echo location of your Java installation.
+
+goto fail
+
+:findJavaFromJavaHome
+set JAVA_HOME=%JAVA_HOME:"=%
+set JAVA_EXE=%JAVA_HOME%/bin/java.exe
+
+if exist "%JAVA_EXE%" goto init
+
+echo.
+echo ERROR: JAVA_HOME is set to an invalid directory: %JAVA_HOME%
+echo.
+echo Please set the JAVA_HOME variable in your environment to match the
+echo location of your Java installation.
+
+goto fail
+
+:init
+@rem Get command-line arguments, handling Windows variants
+
+if not "%OS%" == "Windows_NT" goto win9xME_args
+
+:win9xME_args
+@rem Slurp the command line arguments.
+set CMD_LINE_ARGS=
+set _SKIP=2
+
+:win9xME_args_slurp
+if "x%~1" == "x" goto execute
+
+set CMD_LINE_ARGS=%*
+
+:execute
+@rem Setup the command line
+
+set CLASSPATH=%APP_HOME%\gradle\wrapper\gradle-wrapper.jar
+
+@rem Execute Gradle
+"%JAVA_EXE%" %DEFAULT_JVM_OPTS% %JAVA_OPTS% %GRADLE_OPTS% "-Dorg.gradle.appname=%APP_BASE_NAME%" -classpath "%CLASSPATH%" org.gradle.wrapper.GradleWrapperMain %CMD_LINE_ARGS%
+
+:end
+@rem End local scope for the variables with windows NT shell
+if "%ERRORLEVEL%"=="0" goto mainEnd
+
+:fail
+rem Set variable GRADLE_EXIT_CONSOLE if you need the _script_ return code instead of
+rem the _cmd.exe /c_ return code!
+if  not "" == "%GRADLE_EXIT_CONSOLE%" exit 1
+exit /b 1
+
+:mainEnd
+if "%OS%"=="Windows_NT" endlocal
+
+:omega

DevBytesRepository/settings.gradle

@@ -0,0 +1,17 @@
+/*
+ * Copyright (C) 2019 Google Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+include ':app'

DevBytesWorkManager/README.md

@@ -0,0 +1,56 @@
+DevByteWorkManager - Solution Code
+==================================
+
+Solution code for the WorkManager codelab.
+
+Introduction
+------------
+
+DevByteWorkManager app displays a list of DevByte videos. DevByte videos are
+short videos made by the Google Android developer relations team to introduce
+new developer features on Android. This app fetches the DevByte video playlist
+from the network using the Retrofit library and displays it on the screen. The
+network fetch is scheduled periodically once a day using the WorkManager.
+Constraints like device idle, unmettered network and so on are added to the work
+request to optimise the battery performance.
+
+
+Pre-requisites
+--------------
+
+You need to know:
+- How to open, build, and run Android apps with Android Studio.
+- The Android Architecture Components like, ViewModel, LiveData, and Room.
+- Building and launching a coroutine.
+- Read the logs using the Logcat.
+- Binding adapters in Data Binding.
+- How to use Retrofit network library.
+- Loading cached data using a Repository pattern.
+ 
+
+
+Getting Started
+---------------
+
+1. Download and run the app.
+2. You need Android Studio 3.2 or higher to build this project.
+
+License
+-------
+
+Copyright 2019 Google, Inc.
+
+Licensed to the Apache Software Foundation (ASF) under one or more contributor
+license agreements.  See the NOTICE file distributed with this work for
+additional information regarding copyright ownership.  The ASF licenses this
+file to you under the Apache License, Version 2.0 (the "License"); you may not
+use this file except in compliance with the License.  You may obtain a copy of
+the License at
+
+  http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.  See the
+License for the specific language governing permissions and limitations under
+the License.

DevBytesWorkManager/app/build.gradle

@@ -0,0 +1,106 @@
+/*
+ * Copyright (C) 2019 Google Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+apply plugin: 'com.android.application'
+apply plugin: 'kotlin-android'
+apply plugin: 'kotlin-kapt'
+apply plugin: "androidx.navigation.safeargs"
+apply plugin: 'kotlin-android-extensions'
+
+android {
+    compileSdkVersion 28
+    defaultConfig {
+        applicationId "com.example.android.devbyteviewer"
+        minSdkVersion 19
+        targetSdkVersion 28
+        versionCode 1
+        versionName "1.0"
+        testInstrumentationRunner "androidx.test.runner.AndroidJUnitRunner"
+        vectorDrawables.useSupportLibrary = true
+    }
+    buildTypes {
+        release {
+            minifyEnabled true
+            proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
+        }
+    }
+
+    dataBinding {
+        enabled = true
+    }
+
+}
+
+dependencies {
+    implementation fileTree(dir: 'libs', include: ['*.jar'])
+    implementation "org.jetbrains.kotlin:kotlin-stdlib-jdk7:$kotlin_version"
+
+    // support libraries
+    implementation 'androidx.appcompat:appcompat:1.0.2'
+    implementation 'androidx.legacy:legacy-support-v4:1.0.0'
+    implementation 'com.google.android.material:material:1.0.0'
+
+    // Android KTX
+    implementation 'androidx.core:core-ktx:1.0.2'
+
+    // constraint layout
+    implementation 'androidx.constraintlayout:constraintlayout:1.1.3'
+
+    // navigation
+    def nav_version = "1.0.0"
+    implementation "android.arch.navigation:navigation-fragment-ktx:$nav_version"
+    implementation "android.arch.navigation:navigation-ui-ktx:$nav_version"
+
+    // coroutines for getting off the UI thread
+    def coroutines = "1.0.1"
+    implementation "org.jetbrains.kotlinx:kotlinx-coroutines-core:$coroutines"
+    implementation "org.jetbrains.kotlinx:kotlinx-coroutines-android:$coroutines"
+
+    // retrofit for networking
+    implementation 'com.squareup.retrofit2:retrofit:2.5.0'
+    implementation 'com.jakewharton.retrofit:retrofit2-kotlin-coroutines-adapter:0.9.2'
+    implementation 'com.squareup.retrofit2:converter-moshi:2.5.0'
+
+    // moshi for parsing the JSON format
+    def moshi_version = "1.6.0"
+    implementation "com.squareup.moshi:moshi:$moshi_version"
+    implementation "com.squareup.moshi:moshi-kotlin:$moshi_version"
+    kapt "com.squareup.moshi:moshi-kotlin-codegen:$moshi_version"
+
+    // joda time library for dealing with time
+    implementation 'joda-time:joda-time:2.10'
+
+    // arch components
+    // ViewModel and LiveData
+    def lifecycle_version = "2.2.0-alpha01"
+    implementation "androidx.lifecycle:lifecycle-extensions:$lifecycle_version"
+
+    // logging
+    implementation 'com.jakewharton.timber:timber:4.7.1'
+
+    // glide for images
+    implementation 'com.github.bumptech.glide:glide:4.8.0'
+    kapt 'com.github.bumptech.glide:compiler:4.7.1'
+
+    // Room dependency
+    def room_version = "2.1.0-beta01"
+    implementation "androidx.room:room-runtime:$room_version"
+    kapt "androidx.room:room-compiler:$room_version"
+
+    // WorkManager dependency
+    def work_version = "1.0.1"
+    implementation "android.arch.work:work-runtime-ktx:$work_version"
+}

DevBytesWorkManager/app/proguard-rules.pro

@@ -0,0 +1,21 @@
+# Add project specific ProGuard rules here.
+# You can control the set of applied configuration files using the
+# proguardFiles setting in build.gradle.
+#
+# For more details, see
+#   http://developer.android.com/guide/developing/tools/proguard.html
+
+# If your project uses WebView with JS, uncomment the following
+# and specify the fully qualified class name to the JavaScript interface
+# class:
+#-keepclassmembers class fqcn.of.javascript.interface.for.webview {
+#   public *;
+#}
+
+# Uncomment this to preserve the line number information for
+# debugging stack traces.
+#-keepattributes SourceFile,LineNumberTable
+
+# If you keep the line number information, uncomment this to
+# hide the original source file name.
+#-renamesourcefileattribute SourceFile

DevBytesWorkManager/app/src/main/AndroidManifest.xml

@@ -0,0 +1,42 @@
+<?xml version="1.0" encoding="utf-8"?>
+<!--
+  ~ Copyright (C) 2019 Google Inc.
+  ~
+  ~ Licensed under the Apache License, Version 2.0 (the "License");
+  ~ you may not use this file except in compliance with the License.
+  ~ You may obtain a copy of the License at
+  ~
+  ~     http://www.apache.org/licenses/LICENSE-2.0
+  ~
+  ~ Unless required by applicable law or agreed to in writing, software
+  ~ distributed under the License is distributed on an "AS IS" BASIS,
+  ~ WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+  ~ See the License for the specific language governing permissions and
+  ~ limitations under the License.
+  -->
+
+<manifest xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:tools="http://schemas.android.com/tools"
+    package="com.example.android.devbyteviewer">
+
+    <uses-permission android:name="android.permission.INTERNET" />
+
+    <application
+        android:name=".DevByteApplication"
+        android:allowBackup="true"
+        android:icon="@mipmap/ic_launcher"
+        android:label="@string/app_name"
+        android:roundIcon="@mipmap/ic_launcher_round"
+        android:supportsRtl="true"
+        android:theme="@style/AppTheme"
+        tools:ignore="GoogleAppIndexingWarning">
+        <activity android:name=".ui.DevByteActivity">
+            <intent-filter>
+                <action android:name="android.intent.action.MAIN" />
+
+                <category android:name="android.intent.category.LAUNCHER" />
+            </intent-filter>
+        </activity>
+    </application>
+
+</manifest>

DevBytesWorkManager/app/src/main/java/com/example/android/devbyteviewer/DevByteApplication.kt

@@ -0,0 +1,81 @@
+/*
+ * Copyright (C) 2019 Google Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.example.android.devbyteviewer
+
+import android.app.Application
+import android.os.Build
+import androidx.work.*
+
+import com.example.android.devbyteviewer.work.RefreshDataWorker
+import kotlinx.coroutines.CoroutineScope
+import kotlinx.coroutines.Dispatchers
+import kotlinx.coroutines.launch
+import timber.log.Timber
+import java.util.concurrent.TimeUnit
+
+/**
+ * Override application to setup background work via WorkManager
+ */
+class DevByteApplication : Application() {
+
+    private val applicationScope = CoroutineScope(Dispatchers.Default)
+
+    /**
+     * onCreate is called before the first screen is shown to the user.
+     *
+     * Use it to setup any background tasks, running expensive setup operations in a background
+     * thread to avoid delaying app start.
+     */
+    override fun onCreate() {
+        super.onCreate()
+        delayedInit()
+    }
+
+    private fun delayedInit() {
+        applicationScope.launch {
+            Timber.plant(Timber.DebugTree())
+            setupRecurringWork()
+        }
+    }
+
+    /**
+     * Setup WorkManager background job to 'fetch' new network data daily.
+     */
+    private fun setupRecurringWork() {
+
+        val constraints = Constraints.Builder()
+                .setRequiredNetworkType(NetworkType.UNMETERED)
+                .setRequiresCharging(true)
+                .setRequiresBatteryNotLow(true)
+                .apply {
+                    if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
+                        setRequiresDeviceIdle(true)
+                    }
+                }
+                .build()
+
+        val repeatingRequest = PeriodicWorkRequestBuilder<RefreshDataWorker>(1, TimeUnit.DAYS)
+                .setConstraints(constraints)
+                .build()
+
+        Timber.d("WorkManager: Periodic Work request for sync is scheduled")
+        WorkManager.getInstance().enqueueUniquePeriodicWork(
+                RefreshDataWorker.WORK_NAME,
+                ExistingPeriodicWorkPolicy.KEEP,
+                repeatingRequest)
+    }
+}

DevBytesWorkManager/app/src/main/java/com/example/android/devbyteviewer/database/DatabaseEntities.kt

@@ -0,0 +1,55 @@
+/*
+ * Copyright (C) 2019 Google Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.example.android.devbyteviewer.database
+
+import androidx.room.Entity
+import androidx.room.PrimaryKey
+import com.example.android.devbyteviewer.domain.DevByteVideo
+
+
+/**
+ * Database entities go in this file. These are responsible for reading and writing from the
+ * database.
+ */
+
+
+/**
+ * DatabaseVideo represents a video entity in the database.
+ */
+@Entity
+data class DatabaseVideo constructor(
+        @PrimaryKey
+        val url: String,
+        val updated: String,
+        val title: String,
+        val description: String,
+        val thumbnail: String)
+
+
+/**
+ * Map DatabaseVideos to domain entities
+ */
+fun List<DatabaseVideo>.asDomainModel(): List<DevByteVideo> {
+    return map {
+        DevByteVideo(
+                url = it.url,
+                title = it.title,
+                description = it.description,
+                updated = it.updated,
+                thumbnail = it.thumbnail)
+    }
+}

DevBytesWorkManager/app/src/main/java/com/example/android/devbyteviewer/database/Room.kt

@@ -0,0 +1,50 @@
+/*
+ * Copyright (C) 2019 Google Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.example.android.devbyteviewer.database
+
+import android.content.Context
+import androidx.lifecycle.LiveData
+import androidx.room.*
+
+@Dao
+interface VideoDao {
+    @Query("select * from databasevideo")
+    fun getVideos(): LiveData<List<DatabaseVideo>>
+
+    @Insert(onConflict = OnConflictStrategy.REPLACE)
+    fun insertAll( videos: List<DatabaseVideo>)
+}
+
+
+
+@Database(entities = [DatabaseVideo::class], version = 1)
+abstract class VideosDatabase: RoomDatabase() {
+    abstract val videoDao: VideoDao
+}
+
+private lateinit var INSTANCE: VideosDatabase
+
+fun getDatabase(context: Context): VideosDatabase {
+    synchronized(VideosDatabase::class.java) {
+        if (!::INSTANCE.isInitialized) {
+            INSTANCE = Room.databaseBuilder(context.applicationContext,
+                    VideosDatabase::class.java,
+                    "videos").build()
+        }
+    }
+    return INSTANCE
+}

DevBytesWorkManager/app/src/main/java/com/example/android/devbyteviewer/domain/Models.kt

@@ -0,0 +1,43 @@
+/*
+ * Copyright (C) 2019 Google Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.example.android.devbyteviewer.domain
+
+import com.example.android.devbyteviewer.util.smartTruncate
+
+/**
+ * Domain objects are plain Kotlin data classes that represent the things in our app. These are the
+ * objects that should be displayed on screen, or manipulated by the app.
+ *
+ * @see database for objects that are mapped to the database
+ * @see network for objects that parse or prepare network calls
+ */
+
+/**
+ * Videos represent a devbyte that can be played.
+ */
+data class DevByteVideo(val title: String,
+                        val description: String,
+                        val url: String,
+                        val updated: String,
+                        val thumbnail: String) {
+
+    /**
+     * Short description is used for displaying truncated descriptions in the UI
+     */
+    val shortDescription: String
+        get() = description.smartTruncate(200)
+}

DevBytesWorkManager/app/src/main/java/com/example/android/devbyteviewer/network/DataTransferObjects.kt

@@ -0,0 +1,83 @@
+/*
+ * Copyright (C) 2019 Google Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.example.android.devbyteviewer.network
+
+import com.example.android.devbyteviewer.database.DatabaseVideo
+import com.example.android.devbyteviewer.domain.DevByteVideo
+import com.squareup.moshi.JsonClass
+
+/**
+ * DataTransferObjects go in this file. These are responsible for parsing responses from the server
+ * or formatting objects to send to the server. You should convert these to domain objects before
+ * using them.
+ *
+ * @see domain package for
+ */
+
+/**
+ * VideoHolder holds a list of Videos.
+ *
+ * This is to parse first level of our network result which looks like
+ *
+ * {
+ *   "videos": []
+ * }
+ */
+@JsonClass(generateAdapter = true)
+data class NetworkVideoContainer(val videos: List<NetworkVideo>)
+
+/**
+ * Videos represent a devbyte that can be played.
+ */
+@JsonClass(generateAdapter = true)
+data class NetworkVideo(
+        val title: String,
+        val description: String,
+        val url: String,
+        val updated: String,
+        val thumbnail: String,
+        val closedCaptions: String?)
+
+/**
+ * Convert Network results to database objects
+ */
+fun NetworkVideoContainer.asDomainModel(): List<DevByteVideo> {
+    return videos.map {
+        DevByteVideo(
+                title = it.title,
+                description = it.description,
+                url = it.url,
+                updated = it.updated,
+                thumbnail = it.thumbnail)
+    }
+}
+
+
+/**
+ * Convert Network results to database objects
+ */
+fun NetworkVideoContainer.asDatabaseModel(): List<DatabaseVideo> {
+    return videos.map {
+        DatabaseVideo(
+                title = it.title,
+                description = it.description,
+                url = it.url,
+                updated = it.updated,
+                thumbnail = it.thumbnail)
+    }
+}
+

DevBytesWorkManager/app/src/main/java/com/example/android/devbyteviewer/network/Service.kt

@@ -0,0 +1,54 @@
+/*
+ * Copyright (C) 2019 Google Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.example.android.devbyteviewer.network
+
+import com.jakewharton.retrofit2.adapter.kotlin.coroutines.CoroutineCallAdapterFactory
+import kotlinx.coroutines.Deferred
+import retrofit2.Retrofit
+import retrofit2.converter.moshi.MoshiConverterFactory
+import retrofit2.http.GET
+
+// Since we only have one service, this can all go in one file.
+// If you add more services, split this to multiple files and make sure to share the retrofit
+// object between services.
+
+/**
+ * A retrofit service to fetch devbyte playlist.
+ */
+
+interface DevbyteService {
+    @GET("devbytes")
+    fun getPlaylist(): Deferred<NetworkVideoContainer>
+}
+
+/**
+ * Main entry point for network access. Call like `DevByteNetwork.devbytes.getPlaylist()`
+ */
+object DevByteNetwork {
+
+    // Configure retrofit to parse JSON and use coroutines
+    private val retrofit = Retrofit.Builder()
+            .baseUrl("https://android-kotlin-fun-mars-server.appspot.com/")
+            .addConverterFactory(MoshiConverterFactory.create())
+            .addCallAdapterFactory(CoroutineCallAdapterFactory())
+            .build()
+
+    val devbytes = retrofit.create(DevbyteService::class.java)
+
+}
+
+

DevBytesWorkManager/app/src/main/java/com/example/android/devbyteviewer/repository/VideosRepository.kt

@@ -0,0 +1,54 @@
+/*
+ * Copyright (C) 2019 Google Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.example.android.devbyteviewer.repository
+
+import androidx.lifecycle.LiveData
+import androidx.lifecycle.Transformations
+import com.example.android.devbyteviewer.database.VideosDatabase
+import com.example.android.devbyteviewer.database.asDomainModel
+import com.example.android.devbyteviewer.domain.DevByteVideo
+import com.example.android.devbyteviewer.network.DevByteNetwork
+import com.example.android.devbyteviewer.network.asDatabaseModel
+import kotlinx.coroutines.Dispatchers
+import kotlinx.coroutines.withContext
+import timber.log.Timber
+
+/**
+ * Repository for fetching devbyte videos from the network and storing them on disk
+ */
+class VideosRepository(private val database: VideosDatabase) {
+
+    val videos: LiveData<List<DevByteVideo>> = Transformations.map(database.videoDao.getVideos()) {
+        it.asDomainModel()
+    }
+
+    /**
+     * Refresh the videos stored in the offline cache.
+     *
+     * This function uses the IO dispatcher to ensure the database insert database operation
+     * happens on the IO dispatcher. By switching to the IO dispatcher using `withContext` this
+     * function is now safe to call from any thread including the Main thread.
+     *
+     */
+    suspend fun refreshVideos() {
+        withContext(Dispatchers.IO) {
+            Timber.d("refresh videos is called");
+            val playlist = DevByteNetwork.devbytes.getPlaylist().await()
+            database.videoDao.insertAll(playlist.asDatabaseModel())
+        }
+    }
+}

DevBytesWorkManager/app/src/main/java/com/example/android/devbyteviewer/ui/DevByteActivity.kt

@@ -0,0 +1,37 @@
+/*
+ * Copyright (C) 2019 Google Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.example.android.devbyteviewer.ui
+
+import android.os.Bundle
+import androidx.appcompat.app.AppCompatActivity
+import com.example.android.devbyteviewer.R
+
+/**
+ * This is a single activity application that uses the Navigation library. Content is displayed
+ * by Fragments.
+ */
+class DevByteActivity : AppCompatActivity() {
+
+    /**
+     * Called when the activity is starting.  This is where most initialization
+     * should go
+     */
+    override fun onCreate(savedInstanceState: Bundle?) {
+        super.onCreate(savedInstanceState)
+        setContentView(R.layout.activity_dev_byte_viewer)
+    }
+}

DevBytesWorkManager/app/src/main/java/com/example/android/devbyteviewer/ui/DevByteFragment.kt

@@ -0,0 +1,225 @@
+/*
+ * Copyright (C) 2019 Google Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.example.android.devbyteviewer.ui
+
+import android.content.Intent
+import android.net.Uri
+import android.os.Bundle
+import android.view.LayoutInflater
+import android.view.View
+import android.view.ViewGroup
+import android.widget.Toast
+import androidx.annotation.LayoutRes
+import androidx.databinding.DataBindingUtil
+import androidx.fragment.app.Fragment
+import androidx.lifecycle.Observer
+import androidx.lifecycle.ViewModelProviders
+import androidx.recyclerview.widget.LinearLayoutManager
+import androidx.recyclerview.widget.RecyclerView
+import com.example.android.devbyteviewer.R
+import com.example.android.devbyteviewer.databinding.DevbyteItemBinding
+import com.example.android.devbyteviewer.databinding.FragmentDevByteBinding
+import com.example.android.devbyteviewer.domain.DevByteVideo
+import com.example.android.devbyteviewer.viewmodels.DevByteViewModel
+
+/**
+ * Show a list of DevBytes on screen.
+ */
+class DevByteFragment : Fragment() {
+
+    /**
+     * One way to delay creation of the viewModel until an appropriate lifecycle method is to use
+     * lazy. This requires that viewModel not be referenced before onActivityCreated, which we
+     * do in this Fragment.
+     */
+    private val viewModel: DevByteViewModel by lazy {
+        val activity = requireNotNull(this.activity) {
+            "You can only access the viewModel after onActivityCreated()"
+        }
+        ViewModelProviders.of(this, DevByteViewModel.Factory(activity.application))
+                .get(DevByteViewModel::class.java)
+    }
+
+    /**
+     * RecyclerView Adapter for converting a list of Video to cards.
+     */
+    private var viewModelAdapter: DevByteAdapter? = null
+
+    /**
+     * Called when the fragment's activity has been created and this
+     * fragment's view hierarchy instantiated.  It can be used to do final
+     * initialization once these pieces are in place, such as retrieving
+     * views or restoring state.
+     */
+    override fun onActivityCreated(savedInstanceState: Bundle?) {
+        super.onActivityCreated(savedInstanceState)
+        viewModel.playlist.observe(viewLifecycleOwner, Observer<List<DevByteVideo>> { videos ->
+            videos?.apply {
+                viewModelAdapter?.videos = videos
+            }
+        })
+    }
+
+    /**
+     * Called to have the fragment instantiate its user interface view.
+     *
+     * <p>If you return a View from here, you will later be called in
+     * {@link #onDestroyView} when the view is being released.
+     *
+     * @param inflater The LayoutInflater object that can be used to inflate
+     * any views in the fragment,
+     * @param container If non-null, this is the parent view that the fragment's
+     * UI should be attached to.  The fragment should not add the view itself,
+     * but this can be used to generate the LayoutParams of the view.
+     * @param savedInstanceState If non-null, this fragment is being re-constructed
+     * from a previous saved state as given here.
+     *
+     * @return Return the View for the fragment's UI.
+     */
+    override fun onCreateView(inflater: LayoutInflater, container: ViewGroup?,
+                              savedInstanceState: Bundle?): View? {
+        val binding: FragmentDevByteBinding = DataBindingUtil.inflate(
+                inflater,
+                R.layout.fragment_dev_byte,
+                container,
+                false)
+        // Set the lifecycleOwner so DataBinding can observe LiveData
+        binding.setLifecycleOwner(viewLifecycleOwner)
+
+        binding.viewModel = viewModel
+
+        viewModelAdapter = DevByteAdapter(VideoClick {
+            // When a video is clicked this block or lambda will be called by DevByteAdapter
+
+            // context is not around, we can safely discard this click since the Fragment is no
+            // longer on the screen
+            val packageManager = context?.packageManager ?: return@VideoClick
+
+            // Try to generate a direct intent to the YouTube app
+            var intent = Intent(Intent.ACTION_VIEW, it.launchUri)
+            if(intent.resolveActivity(packageManager) == null) {
+                // YouTube app isn't found, use the web url
+                intent = Intent(Intent.ACTION_VIEW, Uri.parse(it.url))
+            }
+
+            startActivity(intent)
+        })
+
+        binding.root.findViewById<RecyclerView>(R.id.recycler_view).apply {
+            layoutManager = LinearLayoutManager(context)
+            adapter = viewModelAdapter
+        }
+
+
+        // Observer for the network error.
+        viewModel.eventNetworkError.observe(this, Observer<Boolean> { isNetworkError ->
+            if (isNetworkError) onNetworkError()
+        })
+
+        return binding.root
+    }
+
+    /**
+     * Method for displaying a Toast error message for network errors.
+     */
+    private fun onNetworkError() {
+        if(!viewModel.isNetworkErrorShown.value!!) {
+            Toast.makeText(activity, "Network Error", Toast.LENGTH_LONG).show()
+            viewModel.onNetworkErrorShown()
+        }
+    }
+
+    /**
+     * Helper method to generate YouTube app links
+     */
+    private val DevByteVideo.launchUri: Uri
+        get() {
+            val httpUri = Uri.parse(url)
+            return Uri.parse("vnd.youtube:" + httpUri.getQueryParameter("v"))
+        }
+}
+
+/**
+ * Click listener for Videos. By giving the block a name it helps a reader understand what it does.
+ *
+ */
+class VideoClick(val block: (DevByteVideo) -> Unit) {
+    /**
+     * Called when a video is clicked
+     *
+     * @param video the video that was clicked
+     */
+    fun onClick(video: DevByteVideo) = block(video)
+}
+
+/**
+ * RecyclerView Adapter for setting up data binding on the items in the list.
+ */
+class DevByteAdapter(val callback: VideoClick) : RecyclerView.Adapter<DevByteViewHolder>() {
+
+    /**
+     * The videos that our Adapter will show
+     */
+    var videos: List<DevByteVideo> = emptyList()
+        set(value) {
+            field = value
+            // For an extra challenge, update this to use the paging library.
+
+            // Notify any registered observers that the data set has changed. This will cause every
+            // element in our RecyclerView to be invalidated.
+            notifyDataSetChanged()
+        }
+
+    /**
+     * Called when RecyclerView needs a new {@link ViewHolder} of the given type to represent
+     * an item.
+     */
+    override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): DevByteViewHolder {
+        val withDataBinding: DevbyteItemBinding = DataBindingUtil.inflate(
+                LayoutInflater.from(parent.context),
+                DevByteViewHolder.LAYOUT,
+                parent,
+                false)
+        return DevByteViewHolder(withDataBinding)
+    }
+
+    override fun getItemCount() = videos.size
+
+    /**
+     * Called by RecyclerView to display the data at the specified position. This method should
+     * update the contents of the {@link ViewHolder#itemView} to reflect the item at the given
+     * position.
+     */
+    override fun onBindViewHolder(holder: DevByteViewHolder, position: Int) {
+        holder.viewDataBinding.also {
+            it.video = videos[position]
+            it.videoCallback = callback
+        }
+    }
+
+}
+
+/**
+ * ViewHolder for DevByte items. All work is done by data binding.
+ */
+class DevByteViewHolder(val viewDataBinding: DevbyteItemBinding) :
+        RecyclerView.ViewHolder(viewDataBinding.root) {
+    companion object {
+        @LayoutRes
+        val LAYOUT = R.layout.devbyte_item
+    }
+}

DevBytesWorkManager/app/src/main/java/com/example/android/devbyteviewer/util/BindingAdapters.kt

@@ -0,0 +1,42 @@
+/*
+ * Copyright (C) 2019 Google Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.example.android.devbyteviewer.util
+
+import android.view.View
+import android.widget.ImageView
+import androidx.databinding.BindingAdapter
+import com.bumptech.glide.Glide
+
+/**
+ * Binding adapter used to hide the spinner once data is available.
+ */
+@BindingAdapter("isNetworkError", "playlist")
+fun hideIfNetworkError(view: View, isNetWorkError: Boolean, playlist: Any?) {
+    view.visibility = if (playlist != null) View.GONE else View.VISIBLE
+
+    if(isNetWorkError) {
+        view.visibility = View.GONE
+    }
+}
+
+/**
+ * Binding adapter used to display images from URL using Glide
+ */
+@BindingAdapter("imageUrl")
+fun setImageUrl(imageView: ImageView, url: String) {
+    Glide.with(imageView.context).load(url).into(imageView)
+}

DevBytesWorkManager/app/src/main/java/com/example/android/devbyteviewer/util/Util.kt

@@ -0,0 +1,49 @@
+/*
+ * Copyright (C) 2019 Google Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.example.android.devbyteviewer.util
+
+private val PUNCTUATION = listOf(", ", "; ", ": ", " ")
+
+/**
+ * Truncate long text with a preference for word boundaries and without trailing punctuation.
+ */
+fun String.smartTruncate(length: Int): String {
+    val words = split(" ")
+    var added = 0
+    var hasMore = false
+    val builder = StringBuilder()
+    for (word in words) {
+        if (builder.length > length) {
+            hasMore = true
+            break
+        }
+        builder.append(word)
+        builder.append(" ")
+        added += 1
+    }
+
+    PUNCTUATION.map {
+        if (builder.endsWith(it)) {
+            builder.replace(builder.length - it.length, builder.length, "")
+        }
+    }
+
+    if (hasMore) {
+        builder.append("...")
+    }
+    return builder.toString()
+}

DevBytesWorkManager/app/src/main/java/com/example/android/devbyteviewer/viewmodels/DevByteViewModel.kt

@@ -0,0 +1,152 @@
+/*
+ * Copyright (C) 2019 Google Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.example.android.devbyteviewer.viewmodels
+
+import android.app.Application
+import androidx.lifecycle.AndroidViewModel
+import androidx.lifecycle.LiveData
+import androidx.lifecycle.MutableLiveData
+import androidx.lifecycle.ViewModel
+import androidx.lifecycle.ViewModelProvider
+import com.example.android.devbyteviewer.database.getDatabase
+import com.example.android.devbyteviewer.domain.DevByteVideo
+import com.example.android.devbyteviewer.network.DevByteNetwork
+import com.example.android.devbyteviewer.network.asDomainModel
+import com.example.android.devbyteviewer.repository.VideosRepository
+import kotlinx.coroutines.*
+import java.io.IOException
+
+/**
+ * DevByteViewModel designed to store and manage UI-related data in a lifecycle conscious way. This
+ * allows data to survive configuration changes such as screen rotations. In addition, background
+ * work such as fetching network results can continue through configuration changes and deliver
+ * results after the new Fragment or Activity is available.
+ *
+ * @param application The application that this viewmodel is attached to, it's safe to hold a
+ * reference to applications across rotation since Application is never recreated during actiivty
+ * or fragment lifecycle events.
+ */
+class DevByteViewModel(application: Application) : AndroidViewModel(application) {
+
+
+    /**
+     * The data source this ViewModel will fetch results from.
+     */
+    private val videosRepository = VideosRepository(getDatabase(application))
+
+    /**
+     * A playlist of videos displayed on the screen.
+     */
+    val playlist = videosRepository.videos
+
+    /**
+     * This is the job for all coroutines started by this ViewModel.
+     *
+     * Cancelling this job will cancel all coroutines started by this ViewModel.
+     */
+    private val viewModelJob = SupervisorJob()
+
+    /**
+     * This is the main scope for all coroutines launched by MainViewModel.
+     *
+     * Since we pass viewModelJob, you can cancel all coroutines launched by uiScope by calling
+     * viewModelJob.cancel()
+     */
+    private val viewModelScope = CoroutineScope(viewModelJob + Dispatchers.Main)
+
+    /**
+     * Event triggered for network error. This is private to avoid exposing a
+     * way to set this value to observers.
+     */
+    private var _eventNetworkError = MutableLiveData<Boolean>(false)
+
+    /**
+     * Event triggered for network error. Views should use this to get access
+     * to the data.
+     */
+    val eventNetworkError: LiveData<Boolean>
+        get() = _eventNetworkError
+
+    /**
+     * Flag to display the error message. This is private to avoid exposing a
+     * way to set this value to observers.
+     */
+    private var _isNetworkErrorShown = MutableLiveData<Boolean>(false)
+
+    /**
+     * Flag to display the error message. Views should use this to get access
+     * to the data.
+     */
+    val isNetworkErrorShown: LiveData<Boolean>
+        get() = _isNetworkErrorShown
+
+    /**
+     * init{} is called immediately when this ViewModel is created.
+     */
+    init {
+        refreshDataFromRepository()
+    }
+
+    /**
+     * Refresh data from the repository. Use a coroutine launch to run in a
+     * background thread.
+     */
+    private fun refreshDataFromRepository() {
+        viewModelScope.launch {
+            try {
+                videosRepository.refreshVideos()
+                _eventNetworkError.value = false
+                _isNetworkErrorShown.value = false
+
+            } catch (networkError: IOException) {
+                // Show a Toast error message and hide the progress bar.
+                if(playlist.value!!.isEmpty())
+                    _eventNetworkError.value = true
+            }
+        }
+    }
+
+
+    /**
+     * Resets the network error flag.
+     */
+    fun onNetworkErrorShown() {
+        _isNetworkErrorShown.value = true
+    }
+
+
+    /**
+     * Cancel all coroutines when the ViewModel is cleared
+     */
+    override fun onCleared() {
+        super.onCleared()
+        viewModelJob.cancel()
+    }
+
+    /**
+     * Factory for constructing DevByteViewModel with parameter
+     */
+    class Factory(val app: Application) : ViewModelProvider.Factory {
+        override fun <T : ViewModel?> create(modelClass: Class<T>): T {
+            if (modelClass.isAssignableFrom(DevByteViewModel::class.java)) {
+                @Suppress("UNCHECKED_CAST")
+                return DevByteViewModel(app) as T
+            }
+            throw IllegalArgumentException("Unable to construct viewmodel")
+        }
+    }
+}

DevBytesWorkManager/app/src/main/java/com/example/android/devbyteviewer/work/RefreshDataWorker.kt

@@ -0,0 +1,46 @@
+/*
+ * Copyright (C) 2019 Google Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.example.android.devbyteviewer.work
+
+import android.content.Context
+import androidx.work.CoroutineWorker
+import androidx.work.WorkerParameters
+import com.example.android.devbyteviewer.database.getDatabase
+import com.example.android.devbyteviewer.repository.VideosRepository
+import retrofit2.HttpException
+import timber.log.Timber
+
+class RefreshDataWorker(appContext: Context, params: WorkerParameters) :
+        CoroutineWorker(appContext, params) {
+
+    companion object {
+        const val WORK_NAME = "com.example.android.devbyteviewer.work.RefreshDataWorker"
+    }
+    override suspend fun doWork(): Result {
+        val database = getDatabase(applicationContext)
+        val repository = VideosRepository(database)
+
+        try {
+            repository.refreshVideos( )
+            Timber.d("WorkManager: Work request for sync is run")
+        } catch (e: HttpException) {
+            return Result.retry()
+        }
+
+        return Result.success()
+    }
+}

DevBytesWorkManager/app/src/main/res/drawable-v24/ic_launcher_foreground.xml

@@ -0,0 +1,50 @@
+<!--
+  ~ Copyright (C) 2019 Google Inc.
+  ~
+  ~ Licensed under the Apache License, Version 2.0 (the "License");
+  ~ you may not use this file except in compliance with the License.
+  ~ You may obtain a copy of the License at
+  ~
+  ~     http://www.apache.org/licenses/LICENSE-2.0
+  ~
+  ~ Unless required by applicable law or agreed to in writing, software
+  ~ distributed under the License is distributed on an "AS IS" BASIS,
+  ~ WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+  ~ See the License for the specific language governing permissions and
+  ~ limitations under the License.
+  -->
+
+<vector xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:aapt="http://schemas.android.com/aapt"
+    android:width="108dp"
+    android:height="108dp"
+    android:viewportWidth="108"
+    android:viewportHeight="108">
+    <path
+        android:fillType="evenOdd"
+        android:pathData="M32,64C32,64 38.39,52.99 44.13,50.95C51.37,48.37 70.14,49.57 70.14,49.57L108.26,87.69L108,109.01L75.97,107.97L32,64Z"
+        android:strokeWidth="1"
+        android:strokeColor="#00000000">
+        <aapt:attr name="android:fillColor">
+            <gradient
+                android:endX="78.5885"
+                android:endY="90.9159"
+                android:startX="48.7653"
+                android:startY="61.0927"
+                android:type="linear">
+                <item
+                    android:color="#44000000"
+                    android:offset="0.0" />
+                <item
+                    android:color="#00000000"
+                    android:offset="1.0" />
+            </gradient>
+        </aapt:attr>
+    </path>
+    <path
+        android:fillColor="#FFFFFF"
+        android:fillType="nonZero"
+        android:pathData="M66.94,46.02L66.94,46.02C72.44,50.07 76,56.61 76,64L32,64C32,56.61 35.56,50.11 40.98,46.06L36.18,41.19C35.45,40.45 35.45,39.3 36.18,38.56C36.91,37.81 38.05,37.81 38.78,38.56L44.25,44.05C47.18,42.57 50.48,41.71 54,41.71C57.48,41.71 60.78,42.57 63.68,44.05L69.11,38.56C69.84,37.81 70.98,37.81 71.71,38.56C72.44,39.3 72.44,40.45 71.71,41.19L66.94,46.02ZM62.94,56.92C64.08,56.92 65,56.01 65,54.88C65,53.76 64.08,52.85 62.94,52.85C61.8,52.85 60.88,53.76 60.88,54.88C60.88,56.01 61.8,56.92 62.94,56.92ZM45.06,56.92C46.2,56.92 47.13,56.01 47.13,54.88C47.13,53.76 46.2,52.85 45.06,52.85C43.92,52.85 43,53.76 43,54.88C43,56.01 43.92,56.92 45.06,56.92Z"
+        android:strokeWidth="1"
+        android:strokeColor="#00000000" />
+</vector>

DevBytesWorkManager/app/src/main/res/drawable/ic_launcher_background.xml

@@ -0,0 +1,186 @@
+<?xml version="1.0" encoding="utf-8"?>
+<!--
+  ~ Copyright (C) 2019 Google Inc.
+  ~
+  ~ Licensed under the Apache License, Version 2.0 (the "License");
+  ~ you may not use this file except in compliance with the License.
+  ~ You may obtain a copy of the License at
+  ~
+  ~     http://www.apache.org/licenses/LICENSE-2.0
+  ~
+  ~ Unless required by applicable law or agreed to in writing, software
+  ~ distributed under the License is distributed on an "AS IS" BASIS,
+  ~ WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+  ~ See the License for the specific language governing permissions and
+  ~ limitations under the License.
+  -->
+
+<vector xmlns:android="http://schemas.android.com/apk/res/android"
+    android:width="108dp"
+    android:height="108dp"
+    android:viewportWidth="108"
+    android:viewportHeight="108">
+    <path
+        android:fillColor="#008577"
+        android:pathData="M0,0h108v108h-108z" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M9,0L9,108"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M19,0L19,108"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M29,0L29,108"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M39,0L39,108"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M49,0L49,108"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M59,0L59,108"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M69,0L69,108"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M79,0L79,108"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M89,0L89,108"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M99,0L99,108"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M0,9L108,9"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M0,19L108,19"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M0,29L108,29"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M0,39L108,39"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M0,49L108,49"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M0,59L108,59"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M0,69L108,69"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M0,79L108,79"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M0,89L108,89"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M0,99L108,99"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M19,29L89,29"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M19,39L89,39"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M19,49L89,49"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M19,59L89,59"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M19,69L89,69"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M19,79L89,79"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M29,19L29,89"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M39,19L39,89"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M49,19L49,89"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M59,19L59,89"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M69,19L69,89"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M79,19L79,89"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+</vector>

DevBytesWorkManager/app/src/main/res/drawable/ic_play_circle_outline_black_48dp.xml

@@ -0,0 +1,25 @@
+<!--
+  ~ Copyright (C) 2019 Google Inc.
+  ~
+  ~ Licensed under the Apache License, Version 2.0 (the "License");
+  ~ you may not use this file except in compliance with the License.
+  ~ You may obtain a copy of the License at
+  ~
+  ~     http://www.apache.org/licenses/LICENSE-2.0
+  ~
+  ~ Unless required by applicable law or agreed to in writing, software
+  ~ distributed under the License is distributed on an "AS IS" BASIS,
+  ~ WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+  ~ See the License for the specific language governing permissions and
+  ~ limitations under the License.
+  -->
+
+<vector android:height="24dp"
+    android:viewportHeight="48"
+    android:viewportWidth="48"
+    android:width="24dp"
+    xmlns:android="http://schemas.android.com/apk/res/android">
+    <path
+        android:fillColor="#000000"
+        android:pathData="M20,33l12,-9 -12,-9v18zM24,4C12.95,4 4,12.95 4,24s8.95,20 20,20 20,-8.95 20,-20S35.05,4 24,4zM24,40c-8.82,0 -16,-7.18 -16,-16S15.18,8 24,8s16,7.18 16,16 -7.18,16 -16,16z" />
+</vector>

DevBytesWorkManager/app/src/main/res/layout/activity_dev_byte_viewer.xml

@@ -0,0 +1,33 @@
+<?xml version="1.0" encoding="utf-8"?>
+<!--
+  ~ Copyright (C) 2019 Google Inc.
+  ~
+  ~ Licensed under the Apache License, Version 2.0 (the "License");
+  ~ you may not use this file except in compliance with the License.
+  ~ You may obtain a copy of the License at
+  ~
+  ~     http://www.apache.org/licenses/LICENSE-2.0
+  ~
+  ~ Unless required by applicable law or agreed to in writing, software
+  ~ distributed under the License is distributed on an "AS IS" BASIS,
+  ~ WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+  ~ See the License for the specific language governing permissions and
+  ~ limitations under the License.
+  -->
+
+<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:app="http://schemas.android.com/apk/res-auto"
+    xmlns:tools="http://schemas.android.com/tools"
+    android:layout_width="match_parent"
+    android:layout_height="match_parent"
+    tools:context=".ui.DevByteActivity">
+
+    <fragment
+        android:layout_width="match_parent"
+        android:layout_height="match_parent"
+        android:id="@+id/my_nav_host_fragment"
+        android:name="androidx.navigation.fragment.NavHostFragment"
+        app:navGraph="@navigation/nav_graph"
+        app:defaultNavHost="true" />
+
+</FrameLayout>

DevBytesWorkManager/app/src/main/res/layout/devbyte_item.xml

@@ -0,0 +1,130 @@
+<?xml version="1.0" encoding="utf-8"?>
+
+<!--
+  ~ Copyright (C) 2019 Google Inc.
+  ~
+  ~ Licensed under the Apache License, Version 2.0 (the "License");
+  ~ you may not use this file except in compliance with the License.
+  ~ You may obtain a copy of the License at
+  ~
+  ~     http://www.apache.org/licenses/LICENSE-2.0
+  ~
+  ~ Unless required by applicable law or agreed to in writing, software
+  ~ distributed under the License is distributed on an "AS IS" BASIS,
+  ~ WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+  ~ See the License for the specific language governing permissions and
+  ~ limitations under the License.
+  -->
+
+<layout xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:app="http://schemas.android.com/apk/res-auto"
+    xmlns:tools="http://schemas.android.com/tools">
+
+    <data>
+
+        <variable
+            name="video"
+            type="com.example.android.devbyteviewer.domain.DevByteVideo" />
+
+        <variable
+            name="videoCallback"
+            type="com.example.android.devbyteviewer.ui.VideoClick" />
+    </data>
+
+    <com.google.android.material.card.MaterialCardView
+        android:layout_width="match_parent"
+        android:layout_height="wrap_content"
+        app:cardCornerRadius="0dp"
+        app:cardElevation="5dp"
+        android:layout_marginTop="8dp"
+        android:layout_marginBottom="16dp">
+
+        <androidx.constraintlayout.widget.ConstraintLayout
+            android:layout_width="match_parent"
+            android:layout_height="wrap_content">
+
+            <androidx.constraintlayout.widget.Guideline
+                android:id="@+id/left_well"
+                android:layout_width="wrap_content"
+                android:layout_height="wrap_content"
+                android:orientation="vertical"
+                app:layout_constraintGuide_begin="8dp" />
+
+            <androidx.constraintlayout.widget.Guideline
+                android:id="@+id/right_well"
+                android:layout_width="wrap_content"
+                android:layout_height="wrap_content"
+                android:layout_marginEnd="8dp"
+                android:orientation="vertical"
+                app:layout_constraintGuide_end="8dp" />
+
+            <ImageView
+                android:id="@+id/play_icon"
+                android:layout_width="wrap_content"
+                android:layout_height="wrap_content"
+                android:layout_marginTop="14dp"
+                app:layout_constraintStart_toStartOf="@+id/left_well"
+                app:layout_constraintTop_toBottomOf="@+id/video_thumbnail"
+                app:srcCompat="@drawable/ic_play_circle_outline_black_48dp" />
+
+            <TextView
+                android:id="@+id/title"
+                android:layout_width="0dp"
+                android:layout_height="wrap_content"
+                android:layout_marginStart="4dp"
+                android:layout_marginTop="16dp"
+                android:text="@{video.title}"
+                android:textAlignment="viewStart"
+                android:textAllCaps="false"
+                android:textColor="@color/text_black"
+                android:textStyle="bold"
+                app:layout_constraintEnd_toStartOf="@+id/right_well"
+                app:layout_constraintStart_toEndOf="@+id/play_icon"
+                app:layout_constraintTop_toBottomOf="@+id/video_thumbnail"
+                tools:text="Video title" />
+
+
+            <TextView
+                android:id="@+id/description"
+                android:layout_width="0dp"
+                android:layout_height="wrap_content"
+                android:layout_marginTop="8dp"
+                android:layout_marginBottom="16dp"
+                android:text="@{video.shortDescription}"
+                android:textAlignment="viewStart"
+                android:textAllCaps="false"
+                android:textColor="@color/text_light"
+                android:textSize="14sp"
+                app:layout_constraintEnd_toEndOf="@+id/right_well"
+                app:layout_constraintStart_toStartOf="@+id/left_well"
+                app:layout_constraintTop_toBottomOf="@+id/title"
+                app:layout_constraintBottom_toBottomOf="parent"
+                tools:text="this is a video @android:string/fingerprint_icon_content_description" />
+
+            <ImageView
+                android:id="@+id/video_thumbnail"
+                android:layout_width="0dp"
+                android:layout_height="0dp"
+                android:adjustViewBounds="false"
+                android:cropToPadding="false"
+                android:scaleType="centerCrop"
+                app:imageUrl="@{video.thumbnail}"
+                app:layout_constraintDimensionRatio="h,4:3"
+                app:layout_constraintEnd_toEndOf="parent"
+                app:layout_constraintStart_toStartOf="parent"
+                app:layout_constraintTop_toTopOf="parent"
+                tools:srcCompat="@tools:sample/backgrounds/scenic" />
+
+            <View
+                android:id="@+id/clickableOverlay"
+                android:layout_width="0dp"
+                android:layout_height="0dp"
+                android:background="?attr/selectableItemBackground"
+                android:onClick="@{() -> videoCallback.onClick(video)}"
+                app:layout_constraintBottom_toBottomOf="parent"
+                app:layout_constraintEnd_toEndOf="parent"
+                app:layout_constraintStart_toStartOf="parent"
+                app:layout_constraintTop_toTopOf="parent" />
+        </androidx.constraintlayout.widget.ConstraintLayout>
+    </com.google.android.material.card.MaterialCardView>
+</layout>

DevBytesWorkManager/app/src/main/res/layout/fragment_dev_byte.xml

@@ -0,0 +1,53 @@
+<?xml version="1.0" encoding="utf-8"?>
+<!--
+  ~ Copyright (C) 2019 Google Inc.
+  ~
+  ~ Licensed under the Apache License, Version 2.0 (the "License");
+  ~ you may not use this file except in compliance with the License.
+  ~ You may obtain a copy of the License at
+  ~
+  ~     http://www.apache.org/licenses/LICENSE-2.0
+  ~
+  ~ Unless required by applicable law or agreed to in writing, software
+  ~ distributed under the License is distributed on an "AS IS" BASIS,
+  ~ WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+  ~ See the License for the specific language governing permissions and
+  ~ limitations under the License.
+  -->
+
+<layout xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:app="http://schemas.android.com/apk/res-auto"
+    xmlns:tools="http://schemas.android.com/tools"
+    tools:context=".ui.DevByteFragment">
+
+    <data>
+        <variable
+            name="viewModel"
+            type="com.example.android.devbyteviewer.viewmodels.DevByteViewModel" />
+    </data>
+
+    <FrameLayout
+        android:layout_width="match_parent"
+        android:layout_height="match_parent"
+        android:background="@color/background_grey">
+
+        <ProgressBar
+            android:id="@+id/loading_spinner"
+            android:layout_width="wrap_content"
+            android:layout_height="wrap_content"
+            app:isNetworkError = "@{safeUnbox(viewModel.eventNetworkError)}"
+            app:playlist = "@{viewModel.playlist}"
+
+
+
+        android:layout_gravity="center" />
+
+        <androidx.recyclerview.widget.RecyclerView
+            android:id="@+id/recycler_view"
+            android:layout_width="match_parent"
+            android:layout_height="match_parent"
+            tools:listitem="@layout/devbyte_item" />
+    </FrameLayout>
+</layout>
+
+

DevBytesWorkManager/app/src/main/res/mipmap-anydpi-v26/ic_launcher.xml

@@ -0,0 +1,21 @@
+<?xml version="1.0" encoding="utf-8"?>
+<!--
+  ~ Copyright (C) 2019 Google Inc.
+  ~
+  ~ Licensed under the Apache License, Version 2.0 (the "License");
+  ~ you may not use this file except in compliance with the License.
+  ~ You may obtain a copy of the License at
+  ~
+  ~     http://www.apache.org/licenses/LICENSE-2.0
+  ~
+  ~ Unless required by applicable law or agreed to in writing, software
+  ~ distributed under the License is distributed on an "AS IS" BASIS,
+  ~ WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+  ~ See the License for the specific language governing permissions and
+  ~ limitations under the License.
+  -->
+
+<adaptive-icon xmlns:android="http://schemas.android.com/apk/res/android">
+    <background android:drawable="@drawable/ic_launcher_background" />
+    <foreground android:drawable="@drawable/ic_launcher_foreground" />
+</adaptive-icon>

DevBytesWorkManager/app/src/main/res/mipmap-anydpi-v26/ic_launcher_round.xml

@@ -0,0 +1,21 @@
+<?xml version="1.0" encoding="utf-8"?>
+<!--
+  ~ Copyright (C) 2019 Google Inc.
+  ~
+  ~ Licensed under the Apache License, Version 2.0 (the "License");
+  ~ you may not use this file except in compliance with the License.
+  ~ You may obtain a copy of the License at
+  ~
+  ~     http://www.apache.org/licenses/LICENSE-2.0
+  ~
+  ~ Unless required by applicable law or agreed to in writing, software
+  ~ distributed under the License is distributed on an "AS IS" BASIS,
+  ~ WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+  ~ See the License for the specific language governing permissions and
+  ~ limitations under the License.
+  -->
+
+<adaptive-icon xmlns:android="http://schemas.android.com/apk/res/android">
+    <background android:drawable="@drawable/ic_launcher_background" />
+    <foreground android:drawable="@drawable/ic_launcher_foreground" />
+</adaptive-icon>

DevBytesWorkManager/app/src/main/res/navigation/nav_graph.xml

@@ -0,0 +1,29 @@
+<?xml version="1.0" encoding="utf-8"?>
+<!--
+  ~ Copyright (C) 2019 Google Inc.
+  ~
+  ~ Licensed under the Apache License, Version 2.0 (the "License");
+  ~ you may not use this file except in compliance with the License.
+  ~ You may obtain a copy of the License at
+  ~
+  ~     http://www.apache.org/licenses/LICENSE-2.0
+  ~
+  ~ Unless required by applicable law or agreed to in writing, software
+  ~ distributed under the License is distributed on an "AS IS" BASIS,
+  ~ WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+  ~ See the License for the specific language governing permissions and
+  ~ limitations under the License.
+  -->
+
+<navigation xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:app="http://schemas.android.com/apk/res-auto"
+    xmlns:tools="http://schemas.android.com/tools"
+    android:id="@+id/nav_graph"
+    app:startDestination="@id/devByte">
+
+    <fragment
+        android:id="@+id/devByte"
+        android:name="com.example.android.devbyteviewer.ui.DevByteFragment"
+        android:label="fragment_dev_byte"
+        tools:layout="@layout/fragment_dev_byte" />
+</navigation>

DevBytesWorkManager/app/src/main/res/values/colors.xml

@@ -0,0 +1,26 @@
+<?xml version="1.0" encoding="utf-8"?>
+<!--
+  ~ Copyright (C) 2019 Google Inc.
+  ~
+  ~ Licensed under the Apache License, Version 2.0 (the "License");
+  ~ you may not use this file except in compliance with the License.
+  ~ You may obtain a copy of the License at
+  ~
+  ~     http://www.apache.org/licenses/LICENSE-2.0
+  ~
+  ~ Unless required by applicable law or agreed to in writing, software
+  ~ distributed under the License is distributed on an "AS IS" BASIS,
+  ~ WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+  ~ See the License for the specific language governing permissions and
+  ~ limitations under the License.
+  -->
+
+<resources>
+    <color name="colorPrimary">#1E8E3E</color>
+    <color name="colorPrimaryDark">#0D652D</color>
+    <color name="colorAccent">#E37400</color>
+
+    <color name="background_grey">#ffDDDDDD</color>
+    <color name="text_light">#ff666666</color>
+    <color name="text_black">#ff222222</color>
+</resources>

DevBytesWorkManager/app/src/main/res/values/strings.xml

@@ -0,0 +1,19 @@
+<!--
+  ~ Copyright (C) 2019 Google Inc.
+  ~
+  ~ Licensed under the Apache License, Version 2.0 (the "License");
+  ~ you may not use this file except in compliance with the License.
+  ~ You may obtain a copy of the License at
+  ~
+  ~     http://www.apache.org/licenses/LICENSE-2.0
+  ~
+  ~ Unless required by applicable law or agreed to in writing, software
+  ~ distributed under the License is distributed on an "AS IS" BASIS,
+  ~ WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+  ~ See the License for the specific language governing permissions and
+  ~ limitations under the License.
+  -->
+
+<resources>
+    <string name="app_name">DevByte Viewer</string>
+</resources>

DevBytesWorkManager/app/src/main/res/values/styles.xml

@@ -0,0 +1,27 @@
+<!--
+  ~ Copyright (C) 2019 Google Inc.
+  ~
+  ~ Licensed under the Apache License, Version 2.0 (the "License");
+  ~ you may not use this file except in compliance with the License.
+  ~ You may obtain a copy of the License at
+  ~
+  ~     http://www.apache.org/licenses/LICENSE-2.0
+  ~
+  ~ Unless required by applicable law or agreed to in writing, software
+  ~ distributed under the License is distributed on an "AS IS" BASIS,
+  ~ WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+  ~ See the License for the specific language governing permissions and
+  ~ limitations under the License.
+  -->
+
+<resources>
+
+    <!-- Base application theme. -->
+    <style name="AppTheme" parent="Theme.AppCompat.Light.DarkActionBar">
+        <!-- Customize your theme here. -->
+        <item name="colorPrimary">@color/colorPrimary</item>
+        <item name="colorPrimaryDark">@color/colorPrimaryDark</item>
+        <item name="colorAccent">@color/colorAccent</item>
+    </style>
+
+</resources>

DevBytesWorkManager/build.gradle

@@ -0,0 +1,45 @@
+/*
+ * Copyright (C) 2019 Google Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+// Top-level build file where you can add configuration options common to all sub-projects/modules.
+
+buildscript {
+    ext.kotlin_version = '1.3.31'
+    repositories {
+        google()
+        jcenter()
+    }
+    dependencies {
+        classpath 'com.android.tools.build:gradle:3.4.0'
+        classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:$kotlin_version"
+        classpath "android.arch.navigation:navigation-safe-args-gradle-plugin:1.0.0"
+
+        // NOTE: Do not place your application dependencies here; they belong
+        // in the individual module build.gradle files
+    }
+}
+
+allprojects {
+    repositories {
+        google()
+        jcenter()
+        maven { url "https://kotlin.bintray.com/kotlinx/" }
+    }
+}
+
+task clean(type: Delete) {
+    delete rootProject.buildDir
+}

DevBytesWorkManager/gradle.properties

@@ -0,0 +1,31 @@
+#
+# Copyright (C) 2019 Google Inc.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+#
+
+# Project-wide Gradle settings.
+# IDE (e.g. Android Studio) users:
+# Gradle settings configured through the IDE *will override*
+# any settings specified in this file.
+# For more details on how to configure your build environment visit
+# http://www.gradle.org/docs/current/userguide/build_environment.html
+# Specifies the JVM arguments used for the daemon process.
+# The setting is particularly useful for tweaking memory settings.
+android.enableJetifier=true
+android.useAndroidX=true
+org.gradle.jvmargs=-Xmx1536m
+# When configured, Gradle will run in incubating parallel mode.
+# This option should only be used with decoupled projects. More details, visit
+# http://www.gradle.org/docs/current/userguide/multi_project_builds.html#sec:decoupled_projects
+# org.gradle.parallel=true

DevBytesWorkManager/gradle/wrapper/gradle-wrapper.properties

@@ -0,0 +1,6 @@
+#Thu Apr 25 13:35:31 PDT 2019
+distributionBase=GRADLE_USER_HOME
+distributionPath=wrapper/dists
+zipStoreBase=GRADLE_USER_HOME
+zipStorePath=wrapper/dists
+distributionUrl=https\://services.gradle.org/distributions/gradle-5.1.1-all.zip

DevBytesWorkManager/gradlew

@@ -0,0 +1,172 @@
+#!/usr/bin/env sh
+
+##############################################################################
+##
+##  Gradle start up script for UN*X
+##
+##############################################################################
+
+# Attempt to set APP_HOME
+# Resolve links: $0 may be a link
+PRG="$0"
+# Need this for relative symlinks.
+while [ -h "$PRG" ] ; do
+    ls=`ls -ld "$PRG"`
+    link=`expr "$ls" : '.*-> \(.*\)$'`
+    if expr "$link" : '/.*' > /dev/null; then
+        PRG="$link"
+    else
+        PRG=`dirname "$PRG"`"/$link"
+    fi
+done
+SAVED="`pwd`"
+cd "`dirname \"$PRG\"`/" >/dev/null
+APP_HOME="`pwd -P`"
+cd "$SAVED" >/dev/null
+
+APP_NAME="Gradle"
+APP_BASE_NAME=`basename "$0"`
+
+# Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
+DEFAULT_JVM_OPTS=""
+
+# Use the maximum available, or set MAX_FD != -1 to use that value.
+MAX_FD="maximum"
+
+warn () {
+    echo "$*"
+}
+
+die () {
+    echo
+    echo "$*"
+    echo
+    exit 1
+}
+
+# OS specific support (must be 'true' or 'false').
+cygwin=false
+msys=false
+darwin=false
+nonstop=false
+case "`uname`" in
+  CYGWIN* )
+    cygwin=true
+    ;;
+  Darwin* )
+    darwin=true
+    ;;
+  MINGW* )
+    msys=true
+    ;;
+  NONSTOP* )
+    nonstop=true
+    ;;
+esac
+
+CLASSPATH=$APP_HOME/gradle/wrapper/gradle-wrapper.jar
+
+# Determine the Java command to use to start the JVM.
+if [ -n "$JAVA_HOME" ] ; then
+    if [ -x "$JAVA_HOME/jre/sh/java" ] ; then
+        # IBM's JDK on AIX uses strange locations for the executables
+        JAVACMD="$JAVA_HOME/jre/sh/java"
+    else
+        JAVACMD="$JAVA_HOME/bin/java"
+    fi
+    if [ ! -x "$JAVACMD" ] ; then
+        die "ERROR: JAVA_HOME is set to an invalid directory: $JAVA_HOME
+
+Please set the JAVA_HOME variable in your environment to match the
+location of your Java installation."
+    fi
+else
+    JAVACMD="java"
+    which java >/dev/null 2>&1 || die "ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+
+Please set the JAVA_HOME variable in your environment to match the
+location of your Java installation."
+fi
+
+# Increase the maximum file descriptors if we can.
+if [ "$cygwin" = "false" -a "$darwin" = "false" -a "$nonstop" = "false" ] ; then
+    MAX_FD_LIMIT=`ulimit -H -n`
+    if [ $? -eq 0 ] ; then
+        if [ "$MAX_FD" = "maximum" -o "$MAX_FD" = "max" ] ; then
+            MAX_FD="$MAX_FD_LIMIT"
+        fi
+        ulimit -n $MAX_FD
+        if [ $? -ne 0 ] ; then
+            warn "Could not set maximum file descriptor limit: $MAX_FD"
+        fi
+    else
+        warn "Could not query maximum file descriptor limit: $MAX_FD_LIMIT"
+    fi
+fi
+
+# For Darwin, add options to specify how the application appears in the dock
+if $darwin; then
+    GRADLE_OPTS="$GRADLE_OPTS \"-Xdock:name=$APP_NAME\" \"-Xdock:icon=$APP_HOME/media/gradle.icns\""
+fi
+
+# For Cygwin, switch paths to Windows format before running java
+if $cygwin ; then
+    APP_HOME=`cygpath --path --mixed "$APP_HOME"`
+    CLASSPATH=`cygpath --path --mixed "$CLASSPATH"`
+    JAVACMD=`cygpath --unix "$JAVACMD"`
+
+    # We build the pattern for arguments to be converted via cygpath
+    ROOTDIRSRAW=`find -L / -maxdepth 1 -mindepth 1 -type d 2>/dev/null`
+    SEP=""
+    for dir in $ROOTDIRSRAW ; do
+        ROOTDIRS="$ROOTDIRS$SEP$dir"
+        SEP="|"
+    done
+    OURCYGPATTERN="(^($ROOTDIRS))"
+    # Add a user-defined pattern to the cygpath arguments
+    if [ "$GRADLE_CYGPATTERN" != "" ] ; then
+        OURCYGPATTERN="$OURCYGPATTERN|($GRADLE_CYGPATTERN)"
+    fi
+    # Now convert the arguments - kludge to limit ourselves to /bin/sh
+    i=0
+    for arg in "$@" ; do
+        CHECK=`echo "$arg"|egrep -c "$OURCYGPATTERN" -`
+        CHECK2=`echo "$arg"|egrep -c "^-"`                                 ### Determine if an option
+
+        if [ $CHECK -ne 0 ] && [ $CHECK2 -eq 0 ] ; then                    ### Added a condition
+            eval `echo args$i`=`cygpath --path --ignore --mixed "$arg"`
+        else
+            eval `echo args$i`="\"$arg\""
+        fi
+        i=$((i+1))
+    done
+    case $i in
+        (0) set -- ;;
+        (1) set -- "$args0" ;;
+        (2) set -- "$args0" "$args1" ;;
+        (3) set -- "$args0" "$args1" "$args2" ;;
+        (4) set -- "$args0" "$args1" "$args2" "$args3" ;;
+        (5) set -- "$args0" "$args1" "$args2" "$args3" "$args4" ;;
+        (6) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" ;;
+        (7) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" "$args6" ;;
+        (8) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" "$args6" "$args7" ;;
+        (9) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" "$args6" "$args7" "$args8" ;;
+    esac
+fi
+
+# Escape application args
+save () {
+    for i do printf %s\\n "$i" | sed "s/'/'\\\\''/g;1s/^/'/;\$s/\$/' \\\\/" ; done
+    echo " "
+}
+APP_ARGS=$(save "$@")
+
+# Collect all arguments for the java command, following the shell quoting and substitution rules
+eval set -- $DEFAULT_JVM_OPTS $JAVA_OPTS $GRADLE_OPTS "\"-Dorg.gradle.appname=$APP_BASE_NAME\"" -classpath "\"$CLASSPATH\"" org.gradle.wrapper.GradleWrapperMain "$APP_ARGS"
+
+# by default we should be in the correct project dir, but when run from Finder on Mac, the cwd is wrong
+if [ "$(uname)" = "Darwin" ] && [ "$HOME" = "$PWD" ]; then
+  cd "$(dirname "$0")"
+fi
+
+exec "$JAVACMD" "$@"

DevBytesWorkManager/gradlew.bat

@@ -0,0 +1,84 @@
+@if "%DEBUG%" == "" @echo off
+@rem ##########################################################################
+@rem
+@rem  Gradle startup script for Windows
+@rem
+@rem ##########################################################################
+
+@rem Set local scope for the variables with windows NT shell
+if "%OS%"=="Windows_NT" setlocal
+
+set DIRNAME=%~dp0
+if "%DIRNAME%" == "" set DIRNAME=.
+set APP_BASE_NAME=%~n0
+set APP_HOME=%DIRNAME%
+
+@rem Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
+set DEFAULT_JVM_OPTS=
+
+@rem Find java.exe
+if defined JAVA_HOME goto findJavaFromJavaHome
+
+set JAVA_EXE=java.exe
+%JAVA_EXE% -version >NUL 2>&1
+if "%ERRORLEVEL%" == "0" goto init
+
+echo.
+echo ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+echo.
+echo Please set the JAVA_HOME variable in your environment to match the
+echo location of your Java installation.
+
+goto fail
+
+:findJavaFromJavaHome
+set JAVA_HOME=%JAVA_HOME:"=%
+set JAVA_EXE=%JAVA_HOME%/bin/java.exe
+
+if exist "%JAVA_EXE%" goto init
+
+echo.
+echo ERROR: JAVA_HOME is set to an invalid directory: %JAVA_HOME%
+echo.
+echo Please set the JAVA_HOME variable in your environment to match the
+echo location of your Java installation.
+
+goto fail
+
+:init
+@rem Get command-line arguments, handling Windows variants
+
+if not "%OS%" == "Windows_NT" goto win9xME_args
+
+:win9xME_args
+@rem Slurp the command line arguments.
+set CMD_LINE_ARGS=
+set _SKIP=2
+
+:win9xME_args_slurp
+if "x%~1" == "x" goto execute
+
+set CMD_LINE_ARGS=%*
+
+:execute
+@rem Setup the command line
+
+set CLASSPATH=%APP_HOME%\gradle\wrapper\gradle-wrapper.jar
+
+@rem Execute Gradle
+"%JAVA_EXE%" %DEFAULT_JVM_OPTS% %JAVA_OPTS% %GRADLE_OPTS% "-Dorg.gradle.appname=%APP_BASE_NAME%" -classpath "%CLASSPATH%" org.gradle.wrapper.GradleWrapperMain %CMD_LINE_ARGS%
+
+:end
+@rem End local scope for the variables with windows NT shell
+if "%ERRORLEVEL%"=="0" goto mainEnd
+
+:fail
+rem Set variable GRADLE_EXIT_CONSOLE if you need the _script_ return code instead of
+rem the _cmd.exe /c_ return code!
+if  not "" == "%GRADLE_EXIT_CONSOLE%" exit 1
+exit /b 1
+
+:mainEnd
+if "%OS%"=="Windows_NT" endlocal
+
+:omega

DevBytesWorkManager/settings.gradle

@@ -0,0 +1,17 @@
+/*
+ * Copyright (C) 2019 Google Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+include ':app'

MarsRealEstateFinal/README.md

@@ -0,0 +1,56 @@
+MarsRealEstateFinal - Solution Code
+===================================
+
+Solution code for Android Kotlin Fundamentals Codelab 8.3 Filtering and detail views with 
+internet data.
+
+Introduction
+------------
+
+MarsRealEstate is a demo app that shows available properties for sale and for rent on Mars.
+The property data is stored on a Web server as a REST web service.  This app demonstrated
+the use of [Retrofit](https://square.github.io/retrofit/) to make REST requests to the 
+web service, [Moshi](https://github.com/square/moshi) to handle the deserialization of the 
+returned JSON to Kotlin data objects, and [Glide](https://bumptech.github.io/glide/) to load and 
+cache images by URL.  
+
+The app also leverages [ViewModel](https://developer.android.com/topic/libraries/architecture/viewmodel),
+[LiveData](https://developer.android.com/topic/libraries/architecture/livedata), 
+[Data Binding](https://developer.android.com/topic/libraries/data-binding/) with binding 
+adapters, and [Navigation](https://developer.android.com/topic/libraries/architecture/navigation/) 
+with the SafeArgs plugin for parameter passing between fragments.
+
+Pre-requisites
+--------------
+
+You need to know:
+- How to create and use fragments.
+- How to navigate between fragments, and use safeArgs to pass data between fragments.
+- How to use architecture components including ViewModel, ViewModelProvider.Factory, LiveData, and LiveData transformations.
+- How to use coroutines for long-running tasks.
+
+
+Getting Started
+---------------
+
+1. Download and run the app.
+
+License
+-------
+
+Copyright 2019 Google, Inc.
+
+Licensed to the Apache Software Foundation (ASF) under one or more contributor
+license agreements.  See the NOTICE file distributed with this work for
+additional information regarding copyright ownership.  The ASF licenses this
+file to you under the Apache License, Version 2.0 (the "License"); you may not
+use this file except in compliance with the License.  You may obtain a copy of
+the License at
+
+  http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.  See the
+License for the specific language governing permissions and limitations under
+the License.

MarsRealEstateFinal/app/.gitignore

@@ -0,0 +1 @@
+/build

MarsRealEstateFinal/app/build.gradle

@@ -0,0 +1,87 @@
+/*
+ * Copyright 2019, The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+apply plugin: 'com.android.application'
+apply plugin: 'kotlin-android'
+apply plugin: 'kotlin-android-extensions'
+apply plugin: 'kotlin-kapt'
+apply plugin: "androidx.navigation.safeargs"
+
+android {
+    compileSdkVersion 28
+    dataBinding {
+        enabled = true
+    }
+    defaultConfig {
+        applicationId "com.example.android.marsrealestate"
+        minSdkVersion 19
+        targetSdkVersion 28
+        versionCode 1
+        versionName "1.0"
+        testInstrumentationRunner "androidx.test.runner.AndroidJUnitRunner"
+    }
+    buildTypes {
+        release {
+            minifyEnabled false
+            proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
+        }
+    }
+    androidExtensions {
+        experimental = true
+    }
+}
+
+dependencies {
+    implementation fileTree(dir: 'libs', include: ['*.jar'])
+
+    // Kotlin
+    implementation "org.jetbrains.kotlin:kotlin-stdlib-jdk7:$version_kotlin"
+
+    // Constraint Layout
+    implementation "androidx.constraintlayout:constraintlayout:$version_constraint_layout"
+
+    // ViewModel and LiveData
+    implementation "androidx.lifecycle:lifecycle-extensions:$version_lifecycle_extensions"
+
+    // Navigation
+    implementation "android.arch.navigation:navigation-fragment-ktx:$version_navigation"
+    implementation "android.arch.navigation:navigation-ui-ktx:$version_navigation"
+
+    // Core with Ktx
+    implementation "androidx.core:core-ktx:$version_core"
+
+    // Moshi
+    implementation "com.squareup.moshi:moshi:$version_moshi"
+    implementation "com.squareup.moshi:moshi-kotlin:$version_moshi"
+
+    // Retrofit with Moshi Converter
+    implementation "com.squareup.retrofit2:retrofit:$version_retrofit"
+    implementation "com.squareup.retrofit2:converter-moshi:$version_retrofit"
+
+    // Coroutines
+    implementation "org.jetbrains.kotlinx:kotlinx-coroutines-core:$version_kotlin_coroutines"
+    implementation "org.jetbrains.kotlinx:kotlinx-coroutines-android:$version_kotlin_coroutines"
+
+    // Retrofit Coroutines Support
+    implementation "com.jakewharton.retrofit:retrofit2-kotlin-coroutines-adapter:$version_retrofit_coroutines_adapter"
+
+    // Glide
+    implementation "com.github.bumptech.glide:glide:$version_glide"
+
+    // RecyclerView
+    implementation "androidx.recyclerview:recyclerview:$version_recyclerview"
+}

MarsRealEstateFinal/app/proguard-rules.pro

@@ -0,0 +1,21 @@
+# Add project specific ProGuard rules here.
+# You can control the set of applied configuration files using the
+# proguardFiles setting in build.gradle.
+#
+# For more details, see
+#   http://developer.android.com/guide/developing/tools/proguard.html
+
+# If your project uses WebView with JS, uncomment the following
+# and specify the fully qualified class name to the JavaScript interface
+# class:
+#-keepclassmembers class fqcn.of.javascript.interface.for.webview {
+#   public *;
+#}
+
+# Uncomment this to preserve the line number information for
+# debugging stack traces.
+#-keepattributes SourceFile,LineNumberTable
+
+# If you keep the line number information, uncomment this to
+# hide the original source file name.
+#-renamesourcefileattribute SourceFile

MarsRealEstateFinal/app/src/main/AndroidManifest.xml

@@ -0,0 +1,40 @@
+<?xml version="1.0" encoding="utf-8"?>
+
+<!--
+  ~ Copyright 2019, The Android Open Source Project
+  ~
+  ~ Licensed under the Apache License, Version 2.0 (the "License");
+  ~ you may not use this file except in compliance with the License.
+  ~ You may obtain a copy of the License at
+  ~
+  ~     http://www.apache.org/licenses/LICENSE-2.0
+  ~
+  ~ Unless required by applicable law or agreed to in writing, software
+  ~ distributed under the License is distributed on an "AS IS" BASIS,
+  ~ WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+  ~ See the License for the specific language governing permissions and
+  ~ limitations under the License.
+  ~
+  -->
+<manifest xmlns:android="http://schemas.android.com/apk/res/android"
+    package="com.example.android.marsrealestate">
+
+    <!-- In order for our app to access the Internet, we need to define this permission. -->
+    <uses-permission android:name="android.permission.INTERNET" />
+
+    <application
+        android:allowBackup="true"
+        android:icon="@mipmap/ic_launcher"
+        android:label="@string/app_name"
+        android:roundIcon="@mipmap/ic_launcher_round"
+        android:supportsRtl="true"
+        android:theme="@style/AppTheme">
+        <activity android:name="com.example.android.marsrealestate.MainActivity">
+            <intent-filter>
+                <action android:name="android.intent.action.MAIN" />
+                <category android:name="android.intent.category.LAUNCHER" />
+            </intent-filter>
+        </activity>
+    </application>
+
+</manifest>

MarsRealEstateFinal/app/src/main/java/com/example/android/marsrealestate/BindingAdapters.kt

@@ -0,0 +1,77 @@
+/*
+ * Copyright 2019, The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+package com.example.android.marsrealestate
+
+import android.view.View
+import android.widget.ImageView
+import androidx.core.net.toUri
+import androidx.databinding.BindingAdapter
+import androidx.recyclerview.widget.RecyclerView
+import com.bumptech.glide.Glide
+import com.bumptech.glide.request.RequestOptions
+import com.example.android.marsrealestate.network.MarsProperty
+import com.example.android.marsrealestate.overview.MarsApiStatus
+import com.example.android.marsrealestate.overview.PhotoGridAdapter
+
+/**
+ * When there is no Mars property data (data is null), hide the [RecyclerView], otherwise show it.
+ */
+@BindingAdapter("listData")
+fun bindRecyclerView(recyclerView: RecyclerView, data: List<MarsProperty>?) {
+    val adapter = recyclerView.adapter as PhotoGridAdapter
+    adapter.submitList(data)
+}
+
+/**
+ * Uses the Glide library to load an image by URL into an [ImageView]
+ */
+@BindingAdapter("imageUrl")
+fun bindImage(imgView: ImageView, imgUrl: String?) {
+    imgUrl?.let {
+        val imgUri = imgUrl.toUri().buildUpon().scheme("https").build()
+        Glide.with(imgView.context)
+                .load(imgUri)
+                .apply(RequestOptions()
+                        .placeholder(R.drawable.loading_animation)
+                        .error(R.drawable.ic_broken_image))
+                .into(imgView)
+    }
+}
+
+/**
+ * This binding adapter displays the [MarsApiStatus] of the network request in an image view.  When
+ * the request is loading, it displays a loading_animation.  If the request has an error, it
+ * displays a broken image to reflect the connection error.  When the request is finished, it
+ * hides the image view.
+ */
+@BindingAdapter("marsApiStatus")
+fun bindStatus(statusImageView: ImageView, status: MarsApiStatus?) {
+    when (status) {
+        MarsApiStatus.LOADING -> {
+            statusImageView.visibility = View.VISIBLE
+            statusImageView.setImageResource(R.drawable.loading_animation)
+        }
+        MarsApiStatus.ERROR -> {
+            statusImageView.visibility = View.VISIBLE
+            statusImageView.setImageResource(R.drawable.ic_connection_error)
+        }
+        MarsApiStatus.DONE -> {
+            statusImageView.visibility = View.GONE
+        }
+    }
+}

MarsRealEstateFinal/app/src/main/java/com/example/android/marsrealestate/MainActivity.kt

@@ -0,0 +1,33 @@
+/*
+ * Copyright 2019, The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+package com.example.android.marsrealestate
+
+import android.os.Bundle
+import androidx.appcompat.app.AppCompatActivity
+
+class MainActivity : AppCompatActivity() {
+
+    /**
+     * Our MainActivity is only responsible for setting the content view that contains the
+     * Navigation Host.
+     */
+    override fun onCreate(savedInstanceState: Bundle?) {
+        super.onCreate(savedInstanceState)
+        setContentView(R.layout.activity_main)
+    }
+}

MarsRealEstateFinal/app/src/main/java/com/example/android/marsrealestate/detail/DetailFragment.kt

@@ -0,0 +1,47 @@
+/*
+ *  Copyright 2019, The Android Open Source Project
+ *
+ *  Licensed under the Apache License, Version 2.0 (the "License");
+ *  you may not use this file except in compliance with the License.
+ *  You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ *  Unless required by applicable law or agreed to in writing, software
+ *  distributed under the License is distributed on an "AS IS" BASIS,
+ *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *  See the License for the specific language governing permissions and
+ *  limitations under the License.
+ */
+
+package com.example.android.marsrealestate.detail
+
+import android.os.Bundle
+import android.view.LayoutInflater
+import android.view.View
+import android.view.ViewGroup
+import androidx.fragment.app.Fragment
+import androidx.lifecycle.ViewModelProviders
+import com.example.android.marsrealestate.databinding.FragmentDetailBinding
+
+/**
+ * This [Fragment] shows the detailed information about a selected piece of Mars real estate.
+ * It sets this information in the [DetailViewModel], which it gets as a Parcelable property
+ * through Jetpack Navigation's SafeArgs.
+ */
+class DetailFragment : Fragment() {
+    override fun onCreateView(inflater: LayoutInflater, container: ViewGroup?,
+                              savedInstanceState: Bundle?): View? {
+
+        val application = requireNotNull(activity).application
+        val binding = FragmentDetailBinding.inflate(inflater)
+        binding.setLifecycleOwner(this)
+
+        val marsProperty = DetailFragmentArgs.fromBundle(arguments!!).selectedProperty
+        val viewModelFactory = DetailViewModelFactory(marsProperty, application)
+        binding.viewModel = ViewModelProviders.of(
+                this, viewModelFactory).get(DetailViewModel::class.java)
+
+        return binding.root
+    }
+}