Architecture components and Kotlin sample

BasicRxJavaSampleKotlin/.gitignore

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+*.iml
+.gradle
+/local.properties
+.idea
+/.idea/workspace.xml
+/.idea/libraries
+.DS_Store
+/build
+/captures
+.externalNativeBuild
+.idea/

BasicRxJavaSampleKotlin/README.md

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+# Room & RxJava Kotlin Sample
+
+This is an API sample to showcase how to use [Room](https://developer.android
+.com/topic/libraries/architecture/room.html), with RxJava's [Flowable](http://reactivex
+.io/RxJava/2.x/javadoc/io/reactivex/Flowable.html) objects in Kotlin.
+
+# Functionality
+The sample app shows an editable user name, stored in the database.
+
+# Implementation
+
+## Data layer
+
+The database is created using Room and has one entity: a `User`. Room generates the corresponding SQLite table at runtime.
+Queries are executed in the `UserDao` class. The user retrieval is done via an observable query implemented using a `Flowable`. Every time the user data is updated, the Flowable object will emit automatically, allowing to update the UI based on the latest data. The Flowable will emit only when the query result contains at least a row. When there is no data to match the query, the Flowable will not emit.
+
+## Presentation layer
+
+The app has a main Activity that displays the data.
+The Activity works with a ViewModel to do the following:
+* subscribe to the emissions of the user name and updates the UI every time there is a new user name emitted
+* notify the ViewModel when the pressed the "Update" and passes the new user name.
+The ViewModel works with the data source to get and save the data.
+
+Room guarantees that the observable query will be triggered on a background thread. In the Activity, the Flowable events are set to be received on the main thread, so the UI can be updated. The insert query is synchronous so it's wrapped in a Completable and executed on a background thread. On completion, the Activity is notified on the main thread.

BasicRxJavaSampleKotlin/app/.gitignore

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+/build

BasicRxJavaSampleKotlin/app/build.gradle

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+/*
+ * Copyright (C) 2017 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-kapt'
+apply plugin: 'kotlin-android-extensions'
+
+android {
+    compileSdkVersion rootProject.ext.compileSdkVersion
+    buildToolsVersion rootProject.ext.buildToolsVersion
+
+    defaultConfig {
+        applicationId "com.example.android.observability"
+        minSdkVersion 15
+        targetSdkVersion 25
+        versionCode 1
+        versionName "1.0"
+        testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner"
+    }
+    buildTypes {
+        release {
+            minifyEnabled true
+            proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
+        }
+    }
+}
+
+dependencies {
+    // Support libraries
+    implementation "com.android.support:appcompat-v7:$rootProject.supportLibraryVersion"
+    implementation "com.android.support:support-v4:$rootProject.supportLibraryVersion"
+    implementation "com.android.support:design:$rootProject.supportLibraryVersion"
+    // Architecture components
+    implementation "android.arch.lifecycle:runtime:$rootProject.architectureComponentsVersion"
+    implementation "android.arch.lifecycle:extensions:$rootProject.architectureComponentsVersion"
+    kapt "android.arch.lifecycle:compiler:$rootProject.architectureComponentsVersion"
+    implementation "android.arch.persistence.room:runtime:$rootProject.architectureComponentsVersion"
+    kapt "android.arch.persistence.room:compiler:$rootProject.architectureComponentsVersion"
+    implementation "android.arch.persistence.room:rxjava2:$rootProject.architectureComponentsVersion"
+
+    // RxJava
+    implementation "io.reactivex.rxjava2:rxandroid:$rootProject.rxandroidVersion"
+    implementation "io.reactivex.rxjava2:rxjava:$rootProject.rxjavaVersion"
+
+    // Dependencies for local unit tests
+    testImplementation "junit:junit:$rootProject.ext.junitVersion"
+    testImplementation "org.mockito:mockito-all:$rootProject.ext.mockitoVersion"
+    testImplementation "org.hamcrest:hamcrest-all:$rootProject.ext.hamcrestVersion"
+    testImplementation "android.arch.core:core-testing:$rootProject.architectureComponentsVersion"
+    testImplementation "org.jetbrains.kotlin:kotlin-stdlib:$kotlin_version"
+    testImplementation "org.jetbrains.kotlin:kotlin-test-junit:$kotlin_version"
+
+    // Android Testing Support Library's runner and rules
+    androidTestImplementation "com.android.support.test:runner:$rootProject.ext.runnerVersion"
+    androidTestImplementation "com.android.support.test:rules:$rootProject.ext.runnerVersion"
+    androidTestImplementation "android.arch.persistence.room:testing:$rootProject.architectureComponentsVersion"
+    androidTestImplementation "android.arch.core:core-testing:$rootProject.architectureComponentsVersion"
+
+    // Dependencies for Android unit tests
+    androidTestImplementation "junit:junit:$rootProject.ext.junitVersion"
+    androidTestImplementation "org.mockito:mockito-core:$rootProject.ext.mockitoVersion"
+    androidTestImplementation 'com.google.dexmaker:dexmaker:1.2'
+    androidTestImplementation 'com.google.dexmaker:dexmaker-mockito:1.2'
+
+    // Espresso UI Testing
+    androidTestImplementation "com.android.support.test.espresso:espresso-core:$rootProject.espressoVersion"
+    androidTestImplementation "com.android.support.test.espresso:espresso-contrib:$rootProject.espressoVersion"
+    androidTestImplementation "com.android.support.test.espresso:espresso-intents:$rootProject.espressoVersion"
+
+    // Resolve conflicts between main and test APK:
+    androidTestImplementation "com.android.support:support-annotations:$rootProject.supportLibraryVersion"
+    androidTestImplementation "com.android.support:support-v4:$rootProject.supportLibraryVersion"
+    androidTestImplementation "com.android.support:appcompat-v7:$rootProject.supportLibraryVersion"
+    androidTestImplementation "com.android.support:design:$rootProject.supportLibraryVersion"
+
+    // Kotlin
+    implementation "org.jetbrains.kotlin:kotlin-stdlib-jre7:$kotlin_version"
+}
+
+configurations.all {
+    resolutionStrategy {
+        force "org.jetbrains.kotlin:kotlin-stdlib:$kotlin_version"
+    }
+}

BasicRxJavaSampleKotlin/app/proguard-rules.pro

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+# Add project specific ProGuard rules here.
+# By default, the flags in this file are appended to flags specified
+# in /Users/florinam/Library/Android/sdk/tools/proguard/proguard-android.txt
+# You can edit the include path and order by changing the proguardFiles
+# directive in build.gradle.
+#
+# For more details, see
+#   http://developer.android.com/guide/developing/tools/proguard.html
+
+# Add any project specific keep options here:
+
+# 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

BasicRxJavaSampleKotlin/app/src/androidTest/java/com/example/android/observability/persistence/UserDaoTest.kt

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+/*
+ * Copyright (C) 2017 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.observability.persistence
+
+import android.arch.core.executor.testing.InstantTaskExecutorRule
+import android.arch.persistence.room.Room
+import android.support.test.InstrumentationRegistry
+import android.support.test.runner.AndroidJUnit4
+import org.junit.After
+import org.junit.Before
+import org.junit.Rule
+import org.junit.Test
+import org.junit.runner.RunWith
+
+/**
+ * Test the implementation of [UserDao]
+ */
+@RunWith(AndroidJUnit4::class)
+class UserDaoTest {
+
+    @get:Rule
+    var instantTaskExecutorRule = InstantTaskExecutorRule()
+
+    private lateinit var database: UsersDatabase
+
+    @Before
+    @Throws(Exception::class)
+    fun initDb() {
+        // using an in-memory database because the information stored here disappears after test
+        database = Room.inMemoryDatabaseBuilder(InstrumentationRegistry.getContext(),
+                UsersDatabase::class.java)
+                // allowing main thread queries, just for testing
+                .allowMainThreadQueries()
+                .build()
+    }
+
+    @After
+    @Throws(Exception::class)
+    fun closeDb() {
+        database.close()
+    }
+
+    @Test
+    fun getUsersWhenNoUserInserted() {
+        database.userDao().getUserById("123")
+                .test()
+                .assertNoValues()
+    }
+
+    @Test
+    fun insertAndGetUser() {
+        // When inserting a new user in the data source
+        database.userDao().insertUser(USER)
+
+        // When subscribing to the emissions of the user
+        database.userDao().getUserById(USER.id)
+                .test()
+                // assertValue asserts that there was only one emission of the user
+                .assertValue { it.id == USER.id && it.userName == USER.userName }
+    }
+
+    @Test
+    fun updateAndGetUser() {
+        // Given that we have a user in the data source
+        database.userDao().insertUser(USER)
+
+        // When we are updating the name of the user
+        val updatedUser = User(USER.id, "new username")
+        database.userDao().insertUser(updatedUser)
+
+        // When subscribing to the emissions of the user
+        database.userDao().getUserById(USER.id)
+                .test()
+                // assertValue asserts that there was only one emission of the user
+                .assertValue { it.id == USER.id && it.userName == "new username" }
+    }
+
+    @Test
+    fun deleteAndGetUser() {
+        // Given that we have a user in the data source
+        database.userDao().insertUser(USER)
+
+        //When we are deleting all users
+        database.userDao().deleteAllUsers()
+        // When subscribing to the emissions of the user
+        database.userDao().getUserById(USER.id)
+                .test()
+                // check that there's no user emitted
+                .assertNoValues()
+    }
+
+    companion object {
+        private val USER = User("id", "username")
+    }
+}

BasicRxJavaSampleKotlin/app/src/main/AndroidManifest.xml

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+<?xml version="1.0" encoding="utf-8"?>
+<!--
+  ~ Copyright (C) 2017 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.observability">
+
+    <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=".ui.UserActivity">
+            <intent-filter>
+                <action android:name="android.intent.action.MAIN"/>
+
+                <category android:name="android.intent.category.LAUNCHER"/>
+            </intent-filter>
+        </activity>
+    </application>
+
+</manifest>

BasicRxJavaSampleKotlin/app/src/main/java/com/example/android/observability/Injection.kt

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+/*
+ * Copyright (C) 2017 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.observability
+
+import android.content.Context
+import com.example.android.observability.persistence.UserDao
+
+import com.example.android.observability.persistence.UsersDatabase
+import com.example.android.observability.ui.ViewModelFactory
+
+/**
+ * Enables injection of data sources.
+ */
+object Injection {
+
+    fun provideUserDataSource(context: Context): UserDao {
+        val database = UsersDatabase.getInstance(context)
+        return database.userDao()
+    }
+
+    fun provideViewModelFactory(context: Context): ViewModelFactory {
+        val dataSource = provideUserDataSource(context)
+        return ViewModelFactory(dataSource)
+    }
+}

BasicRxJavaSampleKotlin/app/src/main/java/com/example/android/observability/persistence/User.kt

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+/*
+ * Copyright (C) 2017 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.observability.persistence
+
+import android.arch.persistence.room.ColumnInfo
+import android.arch.persistence.room.Entity
+import android.arch.persistence.room.PrimaryKey
+import java.util.*
+
+@Entity(tableName = "users")
+data class User(@PrimaryKey
+                @ColumnInfo(name = "userid")
+                val id: String = UUID.randomUUID().toString(),
+                @ColumnInfo(name = "username")
+                val userName: String)