Adds Hilt Example (Dagger @AssistedInject edition)

build.gradle

@@ -4,11 +4,13 @@ buildscript {
     repositories {
         google()
         jcenter()
+        maven { url "https://oss.sonatype.org/content/repositories/snapshots" }
     }
     dependencies {
         classpath "com.android.tools.build:gradle:${Versions.gradlePlugin}"
         classpath "org.jetbrains.kotlin:kotlin-android-extensions:${Versions.kotlin}"
         classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:${Versions.kotlin}"
+        classpath "com.google.dagger:hilt-android-gradle-plugin:${Versions.hilt}"
 
         // Upload with:
         // ./gradlew clean assemble uploadArchives --no-daemon --no-parallel

buildSrc/src/main/java/dependencies.kt

@@ -25,6 +25,7 @@ object Versions {
     const val dagger = "2.27"
     const val daggerAssisted = "0.5.2"
     const val epoxy = "4.0.0"
+    const val hilt = "HEAD-SNAPSHOT" // cause hilt @AssistedInject is not yet published as of time of writing.
     const val koin = "2.0.1"
     const val kotlinCoroutines = "1.4.1"
     const val lottie = "3.4.0"
@@ -54,6 +55,7 @@ object AnnotationProcessors {
     const val dagger = "com.google.dagger:dagger-compiler:${Versions.dagger}"
     const val daggerAssisted = "com.squareup.inject:assisted-inject-processor-dagger2:${Versions.daggerAssisted}"
     const val epoxy = "com.airbnb.android:epoxy-processor:${Versions.epoxy}"
+    const val hilt = "com.google.dagger:hilt-android-compiler:${Versions.hilt}"
     const val lifecycle = "androidx.lifecycle:lifecycle-compiler:${Versions.lifecycle}"
     const val moshi = "com.squareup.moshi:moshi-kotlin-codegen:${Versions.moshi}"
     const val room = "androidx.room:room-compiler:${Versions.room}"
@@ -73,6 +75,7 @@ object Libraries {
     const val fragment = "androidx.fragment:fragment:${Versions.fragment}"
     const val fragmentKtx = "androidx.fragment:fragment-ktx:${Versions.fragment}"
     const val fragmentTesting = "androidx.fragment:fragment-testing:${Versions.fragment}"
+    const val hilt = "com.google.dagger:hilt-android:${Versions.hilt}"
     const val junit = "junit:junit:${Versions.junit}"
     const val koin = "org.koin:koin-android:${Versions.koin}"
     const val kotlin = "org.jetbrains.kotlin:kotlin-stdlib-jdk8:${Versions.kotlin}"

hellodagger/build.gradle

@@ -44,9 +44,8 @@ dependencies {
     implementation Libraries.rxJava
     implementation Libraries.viewModelKtx
     implementation Libraries.multidex
-
-    implementation fileTree(dir: "libs", include: ["*.jar"])
-    implementation project(":mvrx")
+    implementation project(":mvrx-rxjava2")
+    implementation project(":mvrx-mocking")
 
     debugImplementation Libraries.fragmentTesting
 

hellohilt/.gitignore

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

hellohilt/README.md

@@ -0,0 +1,91 @@
+# Dagger Usage Sample for MvRx
+
+This module contains a sample app demonstrating how to setup Hilt and AssistedInject in an app using MvRx.
+
+**NOTE** Hilts bundled implementation of AssistedInject is as time of writing not released.
+So, you will need to use the Snapshot release until Dagger 2.x is released with AssistedInject.
+
+// build.gradle
+buildscript {
+    repositories {
+        google()
+        jcenter()
+        maven { url "https://oss.sonatype.org/content/repositories/snapshots" }
+    }
+    dependencies {
+        classpath "com.google.dagger:hilt-android-gradle-plugin:HEAD-SNAPSHOT"
+        // rest of classpath(s)…
+    }
+}
+
+// module/build.gradle
+```groovy
+repositories {
+    maven { url "https://oss.sonatype.org/content/repositories/snapshots" }
+}
+
+dependencies {
+    def hiltVersion = "HEAD-SNAPSHOT"
+    kapt "com.google.dagger:hilt-android-compiler:${hiltVersion}"
+    implementation "com.google.dagger:hilt-android:${hiltVersion}"
+}
+```
+
+## Key Features
+
+* **Injecting state into ViewModels with AssistedInject**
+
+  Since the `initialState` parameter is only available at runtime, Dagger can not provide this dependency for us. We need the [AssistedInject](https://github.com/square/AssistedInject) library for this purpose.
+
+* **Multibinding setup for AssistedInject Factories**
+
+  Every ViewModel using AssistedInject needs a Factory interface annotated with `@AssistedFactory`. These factories are grouped together under a common parent type [AssistedViewModelFactory](src/main/java/com/airbnb/mvrx/hellohilt/di/AssistedViewModelFactory.kt) to enable a Multibinding Dagger setup.
+
+## Example
+
+* Create your ViewModel with an ``@AssistedInject` constructor, an `@AssistedFactory` implementing `AssistedViewModelFactory`, and a companion object implementing `DaggerMvRxViewModelFactory`.
+
+```kotlin
+class MyViewModel @AssistedInject constructor(
+  @Assisted initialState: MyState,
+  // and other dependencies
+) {
+
+  @AssistedFactory
+  interface Factory: AssistedViewModelFactory<MyViewModel, MyState> {
+    override fun create(initialState: MyState): MyViewModel
+  }
+
+  companion object: HiltMavericksViewModelFactory<MyViewModel, MyState>(MyViewModel::class.java)
+}
+```
+
+* Tell Dagger to include your ViewModel's AssistedInject Factory in a Multibinding map.
+
+```kotlin
+interface AppModule {
+
+    @[Binds IntoMap ViewModelKey(MyViewModel::class)]
+    fun myViewModelFactory(factory: MyViewModel.Factory): AssistedViewModelFactory<*, *>
+
+}
+```
+
+* Add a provision for the Multibinding map in your Dagger component:
+
+```kotlin
+    fun viewModelFactories(): Map<Class<out MavericksViewModel<*>>, AssistedViewModelFactory<*, *>>
+```
+
+* With this setup complete, request your ViewModel in a Fragment as usual, using any of MvRx's ViewModel delegates.
+
+```kotlin
+class MyFragment : BaseMvRxFragment() {
+  val viewModel: MyViewModel by fragmentViewModel()
+}
+```
+
+## How it works
+
+`HiltMavericksViewModelFactory` will try loading the custom entry point from the `SingletonComponent`
+and lookup the viewModel factory using the `viewModelClass` key.

hellohilt/build.gradle

@@ -0,0 +1,51 @@
+apply plugin: "com.android.application"
+apply plugin: "kotlin-android"
+apply plugin: "kotlin-android-extensions"
+apply plugin: 'dagger.hilt.android.plugin'
+apply plugin: "kotlin-kapt"
+
+repositories {
+    maven { url "https://oss.sonatype.org/content/repositories/snapshots" }
+}
+
+android {
+
+    defaultConfig {
+        applicationId "com.airbnb.mvrx.helloHilt"
+        versionCode 1
+        versionName "0.0.1"
+        testInstrumentationRunner "androidx.test.runner.AndroidJUnitRunner"
+    }
+
+    buildTypes {
+        release {
+            minifyEnabled true
+            signingConfig signingConfigs.debug
+        }
+    }
+}
+
+dependencies {
+    kapt AnnotationProcessors.hilt
+
+    implementation Libraries.appcompat
+    implementation Libraries.constraintlayout
+    implementation Libraries.coreKtx
+    implementation Libraries.fragmentKtx
+    implementation Libraries.hilt
+    implementation Libraries.rxJava
+    implementation Libraries.viewModelKtx
+    implementation Libraries.multidex
+    implementation project(":mvrx-rxjava2")
+    implementation project(":mvrx-mocking")
+
+    debugImplementation Libraries.fragmentTesting
+
+    androidTestImplementation InstrumentedTestLibraries.core
+    androidTestImplementation InstrumentedTestLibraries.espresso
+    androidTestImplementation InstrumentedTestLibraries.junit
+
+    testImplementation project(":testing")
+    testImplementation TestLibraries.junit
+    testImplementation TestLibraries.mockk
+}

hellohilt/src/main/AndroidManifest.xml

@@ -0,0 +1,24 @@
+<?xml version="1.0" encoding="utf-8"?>
+<manifest xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:tools="http://schemas.android.com/tools"
+    package="com.airbnb.mvrx.hellohilt">
+
+    <application
+        android:name="com.airbnb.mvrx.hellohilt.HelloHiltApplication"
+        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="com.airbnb.mvrx.hellohilt.MainActivity">
+            <intent-filter>
+                <action android:name="android.intent.action.MAIN" />
+
+                <category android:name="android.intent.category.LAUNCHER" />
+            </intent-filter>
+        </activity>
+    </application>
+
+</manifest>

hellohilt/src/main/java/com/airbnb/mvrx/hellohilt/HelloFragment.kt

@@ -0,0 +1,34 @@
+package com.airbnb.mvrx.hellohilt
+
+import android.os.Bundle
+import android.view.View
+import androidx.fragment.app.Fragment
+import com.airbnb.mvrx.Fail
+import com.airbnb.mvrx.Loading
+import com.airbnb.mvrx.MvRxView
+import com.airbnb.mvrx.Success
+import com.airbnb.mvrx.Uninitialized
+import com.airbnb.mvrx.fragmentViewModel
+import com.airbnb.mvrx.withState
+import dagger.hilt.android.AndroidEntryPoint
+import kotlinx.android.synthetic.main.fragment_hello.helloButton
+import kotlinx.android.synthetic.main.fragment_hello.messageTextView
+
+@AndroidEntryPoint
+class HelloFragment : Fragment(R.layout.fragment_hello), MvRxView {
+
+    val viewModel: HelloViewModel by fragmentViewModel()
+
+    override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
+        helloButton.setOnClickListener { viewModel.sayHello() }
+    }
+
+    override fun invalidate() = withState(viewModel) { state ->
+        helloButton.isEnabled = state.message !is Loading
+        messageTextView.text = when (state.message) {
+            is Uninitialized, is Loading -> getString(R.string.hello_fragment_loading_text)
+            is Success -> state.message()
+            is Fail -> getString(R.string.hello_fragment_failure_text)
+        }
+    }
+}

hellohilt/src/main/java/com/airbnb/mvrx/hellohilt/HelloHiltApplication.kt

@@ -0,0 +1,13 @@
+package com.airbnb.mvrx.hellohilt
+
+import android.app.Application
+import com.airbnb.mvrx.mocking.MockableMavericks
+import dagger.hilt.android.HiltAndroidApp
+
+@HiltAndroidApp
+class HelloHiltApplication : Application() {
+    override fun onCreate() {
+        super.onCreate()
+        MockableMavericks.initialize(this)
+    }
+}

hellohilt/src/main/java/com/airbnb/mvrx/hellohilt/HelloRepository.kt

@@ -0,0 +1,14 @@
+package com.airbnb.mvrx.hellohilt
+
+import io.reactivex.Observable
+import java.util.concurrent.TimeUnit
+import javax.inject.Inject
+
+class HelloRepository @Inject constructor() {
+
+    fun sayHello(): Observable<String> {
+        return Observable
+            .just("Hello, world!")
+            .delay(2, TimeUnit.SECONDS)
+    }
+}

hellohilt/src/main/java/com/airbnb/mvrx/hellohilt/HelloViewModel.kt

@@ -0,0 +1,34 @@
+package com.airbnb.mvrx.hellohilt
+
+import com.airbnb.mvrx.Async
+import com.airbnb.mvrx.BaseMvRxViewModel
+import com.airbnb.mvrx.MvRxState
+import com.airbnb.mvrx.Uninitialized
+import com.airbnb.mvrx.hellohilt.di.AssistedViewModelFactory
+import com.airbnb.mvrx.hellohilt.di.HiltMavericksViewModelFactory
+import dagger.assisted.Assisted
+import dagger.assisted.AssistedFactory
+import dagger.assisted.AssistedInject
+
+data class HelloState(val message: Async<String> = Uninitialized) : MvRxState
+
+class HelloViewModel @AssistedInject constructor(
+    @Assisted state: HelloState,
+    private val repo: HelloRepository
+) : BaseMvRxViewModel<HelloState>(state) {
+
+    init {
+        sayHello()
+    }
+
+    fun sayHello() {
+        repo.sayHello().execute { copy(message = it) }
+    }
+
+    @AssistedFactory
+    interface Factory : AssistedViewModelFactory<HelloViewModel, HelloState> {
+        override fun create(state: HelloState): HelloViewModel
+    }
+
+    companion object : HiltMavericksViewModelFactory<HelloViewModel, HelloState>(HelloViewModel::class.java)
+}

hellohilt/src/main/java/com/airbnb/mvrx/hellohilt/MainActivity.kt

@@ -0,0 +1,7 @@
+package com.airbnb.mvrx.hellohilt
+
+import androidx.appcompat.app.AppCompatActivity
+import dagger.hilt.android.AndroidEntryPoint
+
+@AndroidEntryPoint
+class MainActivity : AppCompatActivity(R.layout.activity_main)

hellohilt/src/main/java/com/airbnb/mvrx/hellohilt/di/AppModule.kt

@@ -0,0 +1,21 @@
+package com.airbnb.mvrx.hellohilt.di
+
+import com.airbnb.mvrx.hellohilt.HelloViewModel
+import dagger.Binds
+import dagger.Module
+import dagger.hilt.InstallIn
+import dagger.hilt.components.SingletonComponent
+import dagger.multibindings.IntoMap
+
+/**
+ * The InstallIn SingletonComponent scope must match the context scope used in [HiltMavericksViewModelFactory]
+ *
+ * If you want an Activity or Fragment scope
+ */
+@Module
+@InstallIn(SingletonComponent::class)
+interface AppModule {
+
+    @[Binds IntoMap ViewModelKey(HelloViewModel::class)]
+    fun helloViewModelFactory(factory: HelloViewModel.Factory): AssistedViewModelFactory<*, *>
+}