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.

Answer 2

the context object is not initialized before its called

Though i dont know, how chained your initialization are.

Use @Inject to add deppendencies, do something like this

    @Module
class BluetoothModule(val context : Context) {

    //@Inject private lateinit var context : Context
    @Provides
    @Named("rxBleClient")
    @Singleton
    fun provideRxBleClient():RxBleClient =
            RxBleClient.create(context)
}

let your call be like this

val component = AppComponent()
 component.bluetoothModule(appContext)
          .//other calls here
          .build()