Kotlin dagger hilt injection is not initialized

Question

i am trying to use dagger hilt, i set up everything, but i am getting and error when i try to use the object for witch i am created a dependency injection: kotlin.UninitializedPropertyAccessException: lateinit property exoPlayer has not been initialized

Here is my module provider:

@Module
@InstallIn(ServiceComponent::class)
object ServiceModule {
    @ServiceScoped
    @Provides
    fun provideExoPlayer(
        @ApplicationContext context: Context,
        audioAttributes: AudioAttributes
    ) = SimpleExoPlayer.Builder(context).build().apply {
        setAudioAttributes(audioAttributes, true)
        setHandleAudioBecomingNoisy(true)
    }
}

In my activity i got:

@AndroidEntryPoint
class AudioActivity : AppCompatActivity(), Player.EventListener { {

    @Inject
    lateinit var exoPlayer: SimpleExoPlayer

then i try to add a listener in the onCreate

exoPlayer.addListener(this)

But here i got the error that it's not initialized, i don't realy understand because i though that the all point of dependency injection was to provide an construct that can be injected everywhere. So why it has not been initialized?

Answer 1

You're actually providing your SimpleExoPlayer object in ServiceComponent . As you're expecting to inject the SimpleExoPlayer in Activity, you should provide it in ActivityComponent instead. I think you may need a module or reuse existing one

@Module
@InstallIn(ActivityComponent::class)
object ActivityModule {
    
    @ActivityScoped
    @Provides
    fun provideExoPlayer(
        @ApplicationContext context: Context,
        audioAttributes: AudioAttributes
    ) = SimpleExoPlayer.Builder(context).build().apply {
        setAudioAttributes(audioAttributes, true)
        setHandleAudioBecomingNoisy(true)
    }
}