Android Kotlin with Dagger2, lateinit var has not been initialized

Question

I'm a Dagger newb and have a trouble with using it.

What I want to develop is that using RxAndroidBle and to initialize it by Dagger for providing Context.

So I researched how it can be implemented, and I wrote some codes and It seems to be working for me but not working at all.

The followings are my codes.

AppComponent.kt

@Singleton
@Component(modules = [
    AppModule::class,
    BluetoothModule::class,
    AndroidInjectionModule::class])
interface AppComponent : AndroidInjector<BluetoothController> {

    @Component.Builder
    interface Builder {

        @BindsInstance
        fun application(app: Application): Builder

        fun build(): AppComponent
    }
}

AppModule.kt

@Module
class AppModule {

    @Provides
    @Named("appContext")
    @Singleton
    fun provideContext(application: Application): Context =
            application.applicationContext
}

BluetoothModule.kt

@Module
class BluetoothModule {

    @Provides
    @Named("rxBleClient")
    @Singleton
    fun provideRxBleClient(@Named("appContext") context: Context):RxBleClient =
            RxBleClient.create(context)
}

BluetoothController.kt for injecting by DaggerApplication.

class BluetoothController : DaggerApplication() {

    override fun applicationInjector(): AndroidInjector<out DaggerApplication> {
        return DaggerAppComponent.builder().application(this).build()
    }
}

I've inserted android:name".BluetoothController" to AndroidManifest.xml

And this is how I would use it.

@field:[Inject Named("rxBleClient")]
lateinit var rxBleClient: RxBleClient

But it always occurs an error says: lateinit property context has not been initialized

What things I've missed? Can anyone help me?

Thanks in advance.

Answer 1

Add the below code to make this happen.

1. Create ActivityBuilderModule for injecting within the activity. Consider our activity as MainActivity

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

2. Create your MainActivityModule

   @Module
   class MainActivityModule{
        @Provides()
        fun contributeSplashActivity(mainActivity: MainActivity): 
           MainActivity=mainActivity
    }
   

3. Modify your component.

   @Singleton
   @Component(modules = [
   AppModule::class,
   BluetoothModule::class,
   ActivityBuilderModule::class,
   AndroidInjectionModule::class])
   interface AppComponent : AndroidInjector<BluetoothController> {
   
       @Component.Builder
       interface Builder {
   
           @BindsInstance
           fun application(app: Application): Builder
   
           fun build(): AppComponent
       }
   }
   

4. Within MainActivity just inject.

   class MainActivity{
         ...
         @Inject
         lateinit var rxBleClient: RxBleClient
         override fun onCreate(savedInstanceState: Bundle?) {
   
           AndroidInjection.inject(this)
           super.onCreate(savedInstanceState)
         }
   }
   

Let us know in case of any issue.