Dagger 2 configuration

Dagger 2.md

Small gist show how to config Dagger 2 to an Android project

build.gradle

// top level build.gradle
buildscript {

  repositories {
    jcenter()
  }
  dependencies {
    classpath 'com.android.tools.build:gradle:1.5.0'
    classpath 'com.neenbedankt.gradle.plugins:android-apt:1.8' // apt for manage code generation
  }
}

allprojects {
  repositories {
    jcenter()
  }
}

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

buld.gradle

// app build.gradle

apply plugin: 'com.android.application'
// Use to manage code generation
apply plugin: 'com.neenbedankt.android-apt'

android {
  compileSdkVersion 23
  buildToolsVersion "23.0.2"

  defaultConfig {
    applicationId "com.lenguyenthanh.nimbledagger2"
    minSdkVersion 15
    targetSdkVersion 23
    versionCode 1
    versionName "1.0"
  }
  buildTypes {
    release {
      minifyEnabled false
      proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
    }
  }
}

dependencies {
  compile 'com.android.support:appcompat-v7:23.2.0'
  compile 'com.android.support:design:23.2.0'

  //Dagger 2 dependency
  compile 'com.google.dagger:dagger:2.0.2'
  apt 'com.google.dagger:dagger-compiler:2.0.2'
  provided 'org.glassfish:javax.annotation:10.0-b28'
}

AppModule.java

// An example module, this module only provides one dependency - DaggerApplication object

@Module
public class AppModule {
  DaggerApplication mApplication;

  public AppModule(DaggerApplication application) {
    mApplication = application;
  }

  @Provides
  @Singleton
  DaggerApplication providesApplication() {
    return mApplication;
  }
}

DaggerApplication.java

// Example Application object, need to declare it in manifest.xml
public class DaggerApplication extends Application{
  protected AppComponent appComponent;

  // provide appComponent to use in other classes
  public AppComponent getAppComponent() {
    return appComponent;
  }

  public static DaggerApplication get(Context context) {
    return (DaggerApplication) context.getApplicationContext();
  }

  @Override
  public void onCreate() {
    super.onCreate();
    initializeDaggerComponent();
  }
  
  // build an instance of AppComponent, we need to keep this instance for another sub components in project
  protected void initializeDaggerComponent() {
    // DaggerDaggerApplication_AppComponent is a generated class. It only appears after first success build.
    appComponent = DaggerDaggerApplication_AppComponent.builder()
        .appModule(new AppModule(this)) // add AppModule instance to the component
        .build();
    appComponent.inject(this); // inject dependencies to this class
  }

  // AppComponent component interface - root component of the project
  @Singleton
  @Component(modules = AppModule.class)
  public interface AppComponent {
    DaggerApplication application();

    void inject(DaggerApplication app);
  }
}