Setting Up Dagger 2, Retrofit, Gson, RxJava2, AndroidInjector

ActivityBuilder.kt

@Module
abstract class ActivityBuilder {
    @ContributesAndroidInjector(modules = [MainActivityModule::class])
    abstract fun bindMainActivity(): MainActivity
}

AndroidManifest.xml

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.example.dell.todoapps">

    <uses-permission android:name="android.permission.INTERNET" />

    <application
        android:name=".application.TodoApplication"
        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.MainActivity.MainActivity">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
        <activity android:name=".ui.SecondActivity.SecondActivity"></activity>
    </application>

</manifest>

app.gradle

apply plugin: 'com.android.application'
apply plugin: 'kotlin-android'
apply plugin: 'kotlin-kapt'
apply plugin: 'kotlin-android-extensions'

android {
    compileSdkVersion 27
    defaultConfig {
        applicationId "com.example.dell.todoapps"
        minSdkVersion 21
        targetSdkVersion 27
        versionCode 1
        versionName "1.0"
        testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner"


        javaCompileOptions {
            annotationProcessorOptions {
                arguments = ["room.schemaLocation": "$projectDir/schemas".toString()]
            }
        }
    }
    buildTypes {
        release {
            minifyEnabled false
            proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
        }
    }
}
kapt {
    generateStubs = true
}
dependencies {

    implementation fileTree(dir: 'libs', include: ['*.jar'])
    implementation "org.jetbrains.kotlin:kotlin-stdlib-jre7:$kotlin_version"
    implementation 'com.android.support:appcompat-v7:27.1.0'
    implementation 'com.android.support.constraint:constraint-layout:1.0.2'

    implementation "io.reactivex.rxjava2:rxjava:$rootProject.rxjavaVersion"
    implementation "io.reactivex.rxjava2:rxandroid:$rootProject.rxandroidVersion"
    implementation "io.reactivex.rxjava2:rxkotlin:$rootProject.rxkotlinVersion"

    implementation "com.squareup.retrofit2:retrofit:$rootProject.retrofitVersion"
    implementation "com.squareup.retrofit2:converter-gson:$rootProject.retrofitVersion"
    implementation 'com.jakewharton.retrofit:retrofit2-rxjava2-adapter:1.0.0'
    implementation "com.squareup.okhttp3:okhttp:$rootProject.okhttpVersion"
    implementation "com.squareup.okhttp3:logging-interceptor:$rootProject.okhttpVersion"
    implementation 'com.google.code.gson:gson:2.8.2'

    implementation "org.jetbrains.kotlin:kotlin-stdlib-jre7:$kotlin_version"

    implementation "com.google.dagger:dagger:$rootProject.daggerVersion"
    implementation "com.google.dagger:dagger-android:$rootProject.daggerVersion"
    implementation "com.google.dagger:dagger-android-support:$rootProject.daggerVersion"
    implementation 'com.google.dagger:dagger-android:2.13'
    implementation 'com.google.dagger:dagger-android-support:2.13'
    kapt "com.google.dagger:dagger-compiler:$rootProject.daggerVersion"
    kapt "com.google.dagger:dagger-android-processor:$rootProject.daggerVersion"
    compileOnly 'org.glassfish:javax.annotation:10.0-b28'
    annotationProcessor 'com.google.dagger:dagger-android-processor:2.13'
    annotationProcessor 'com.google.dagger:dagger-compiler:2.13'

    testImplementation 'junit:junit:4.12'
    androidTestImplementation 'com.android.support.test:runner:1.0.1'
    androidTestImplementation 'com.android.support.test.espresso:espresso-core:3.0.1'
}

AppComponent.kt

@Singleton
@Component(modules = [AndroidInjectionModule::class, AppModule::class, ActivityBuilder::class])
interface AppComponent {
    @Component.Builder
    interface Builder {
        @BindsInstance
        fun application(app: Application): Builder

        fun build(): AppComponent
    }

    fun inject(app: TodoApplication)
}

AppModule.kt

@Module
class AppModule {

    @Provides
    @Singleton
    fun provideGson(): Gson {
        return GsonBuilder()
                .create()
    }

    @Provides
    @Singleton
    fun provideOkHttpClient(application: Application): OkHttpClient {
        val interceptor = HttpLoggingInterceptor()
        interceptor.level = HttpLoggingInterceptor.Level.BASIC
        return OkHttpClient.Builder()
                .addInterceptor(interceptor)
                .build()
    }


    @Provides
    @Singleton
    fun provideApiService(gson: Gson, okHttpClient: OkHttpClient): ApiService {
        return Retrofit.Builder()
                .baseUrl("https://jsonplaceholder.typicode.com")
                .addConverterFactory(GsonConverterFactory.create(gson))
                .addCallAdapterFactory(RxJava2CallAdapterFactory.create())
                .client(okHttpClient)
                .build().create(ApiService::class.java)
    }

}

build.gradle

buildscript {
    ext.kotlin_version = '1.2.30'
    repositories {
        google()
        jcenter()
    }
    dependencies {
        classpath 'com.android.tools.build:gradle:3.1.0'
        classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:$kotlin_version"
    }
}

allprojects {
    repositories {
        google()
        jcenter()
    }
}

task clean(type: Delete) {
    delete rootProject.buildDir
}



ext {
    architectureComponentsVersion = "1.0.0"
    daggerVersion = "2.13"
    retrofitVersion = "2.3.0"
    okhttpVersion = "3.9.0"
    rxjavaVersion = "2.1.3"
    rxandroidVersion = "2.0.1"
    rxkotlinVersion = "2.1.0"
}

DaggerActivity.kt

abstract class DaggerActivity: AppCompatActivity(), HasFragmentInjector {

    @Inject
    lateinit var fragmentInjector: DispatchingAndroidInjector<Fragment>

    override fun fragmentInjector(): AndroidInjector<Fragment> = fragmentInjector

    override fun onCreate(savedInstanceState: Bundle?) {
        AndroidInjection.inject(this)
        super.onCreate(savedInstanceState)
    }
}

MainActivity.kt

class MainActivity : DaggerActivity() {

    @Inject
    lateinit var apiService: ApiService

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)
        button.setOnClickListener {
            startActivity(Intent(this, SecondActivity::class.java))
        }
    }
}

MainActivityModule.kt

@Module
class MainActivityModule {

    @Provides
    fun provideSomething(): Something {
        return Something()
    }
}

Post.kt

data class Post(var userId: Int,
                var id: Int,
                var title: String,
                var body: String)

Something.kt

class Something {
    fun getString() = "Hello World"
}

TodoApplication.kt

class TodoApplication: Application(), HasActivityInjector {

    @Inject
    lateinit var injector: DispatchingAndroidInjector<Activity>

    override fun onCreate() {
        super.onCreate()
        DaggerAppComponent.builder()
                .application(this)
                .build()
                .inject(this)
    }

    override fun activityInjector(): AndroidInjector<Activity> = injector

}