Modular Architecture - Dagger2 - BaseInjector

ApplicationComponent.kt

@Singleton
@Component(modules = arrayOf(NetworkModule::class, RepositoryModule::class))
interface ApplicationComponent : AndroidInjector<MyApplication> {
  
  fun networkSubComponentBuilder(): NetworkSubComponent.Builder;

  fun repositorySubComponentBuilder(): RepositorySubComponent.Builder;
  
}

BaseInjector.kt

/**
* BaseInjector for any class that can provide an Application instance
**/
interface BaseInjector<T : BaseApplicationProvider> : AndroidInjector<T> {
  abstract class Builder<T : BaseApplicationProvider> : dagger.android.AndroidInjector.Builder<T>() {
 
    //declare dependency to BaseSubComponent
    abstract fun plus(component: BaseSubComponent): Builder<T>
 
    fun inject(activity: T) {
      //retrieve BaseSubComponent instance
      plus(activity.baseApplication.provideBaseSubComponent())
      //create and inject activity/fragment/service
      create(activity)
      .inject(activity)
    }
  }
}

BaseSubComponent.kt

@Subcomponent
interface BaseSubComponent : RepositorySubComponent, NetworkSubComponent {
    @dagger.Subcomponent.Builder
    interface Builder {
        fun build(): BaseSubComponent
    }
}

BrowserActivity.kt

class BrowserActivity() : BaseApplicationProvider {
    override val baseApplication: BaseApplication
        get() = application as BaseApplication
}

class BaseApplication() : Application {
    fun provideBaseSubComponent() = applicationComponent.baseSubComponentBuilder().build() 
}

BrowserComponent.kt

@BrowserScope
@Component(modules = arrayOf(BrowserModule::class), 
           dependencies = arrayOf(BaseSubComponent::class))
interface RecipeBrowserFragmentComponent : BaseInjector<BrowserActivity> {
    @Component.Builder
    abstract class Builder : BaseInjector.Builder<BrowserActivity>()
}

RepositorySubComponent.kt

@Subcomponent
interface RepositorySubComponent {

    val sharedPref: SharedPref
    val userRepository: UserRepository

    @Subcomponent.Builder
    interface Builder {
        fun build(): RepositorySubComponent
    }
}