Android匕首2：如果没有@Provides注释的方法，则无法提供依赖项

Question

Dagger 2 dependencies:

implementation "com.google.dagger:dagger:2.15"
kapt "com.google.dagger:dagger-compiler:2.15"

My AppComponent :

@Singleton
@Component(modules = [
    DomainModule::class,
    DataModule::class,
    PresentationModule::class,
    ViewModelModule::class,
    RepositoriesModule::class
])
interface AppComponent {

    //reps
    fun topicsRep(): TopicsRepository
    fun countriesRep(): CountriesRepository
    fun loginRep(): LoginRepository
}

My ViewModelModule class:

@Module
abstract class ViewModelModule {

    @Binds
    internal abstract fun bindViewModelFactory(factory: ViewModelFactory): ViewModelProvider.Factory

    @Binds
    @IntoMap
    @ViewModelKey(LoginViewModel::class)
    internal abstract fun loginViewModel(viewModel: LoginViewModel): ViewModel

    @Binds
    @IntoMap
    @ViewModelKey(CountriesViewModel::class)
    internal abstract fun countriesViewModel(viewModel: CountriesViewModel): ViewModel
}

My ViewModelFactory :

   @Suppress("UNCHECKED_CAST")
@Singleton
class ViewModelFactory
@Inject constructor(private val viewModels: MutableMap<Class<out ViewModel>,
        @JvmSuppressWildcards Provider<ViewModel>>) :
        ViewModelProvider.Factory {

    override fun <T : ViewModel> create(modelClass: Class<T>): T = viewModels[modelClass]?.get() as T
}

@Target(AnnotationTarget.FUNCTION, AnnotationTarget.PROPERTY_GETTER, AnnotationTarget.PROPERTY_SETTER)
@kotlin.annotation.Retention(AnnotationRetention.RUNTIME)
@MapKey
internal annotation class ViewModelKey(val value: KClass<out ViewModel>)

And for example my CountryComponent and CountryModule :

@ActivityScope
@Component(modules = [CountryModule::class], dependencies = [AppComponent::class])
interface CountryComponent {

   fun inject(activity: SelectCountryActivity)
}

@Module
class CountryModule {

    @Provides
    @Singleton
    fun provideCountriesInteractor(rep: CountriesRepository)
             = SelectCountryInteractor(rep)
}

What i am trying to achieve - i need to inject an instance of ViewModelFactory to my activities and fragments. My viewmodels contains others dependensies. Also trying to separate dependencies for each screen.

After build getting error:

CountryComponent.java:10: error: java.util.Map<java.lang.Class<? extends android.arch.lifecycle.ViewModel>,javax.inject.Provider<android.arch.lifecycle.ViewModel>> cannot be provided without an @Provides-annotated method

java.util.Map<java.lang.Class<? extends android.arch.lifecycle.ViewModel>,javax.inject.Provider<android.arch.lifecycle.ViewModel>> is injected at ViewModelFactory.<init>(viewModels)
ViewModelFactory is injected at SelectCountryActivity.factory
SelectCountryActivity is injected at CountryComponent.inject(activity)

When setting ViewModelFactory as @Singleton getting error:

CountryComponent scoped with @ActivityScope may not reference bindings with different scopes:
@dagger.Component(modules = {CountryModule.class}, dependencies = {AppComponent.class})
@Singleton class ViewModelFactory
AppComponent.java:6: error: AppComponent scoped with @Singleton may not reference bindings with different scopes:
@dagger.Component(modules = {DomainModule.class, DataModule.class, PresentationModule.class, ViewModelModule.class, RepositoriesModule.class})

Is there any reason to mark ViewModel as Singleton or ActivityScope ?

Answer 1

Fixed by adding

fun viewModelFactory(): ViewModelFactory

to my AppComponent . Also removed @Singleton from ViewModelFactory