Dagger2 Error in ViewModelFactory when change MutableMap to Map

Question

I have problem when try to use dagger2 Here is my ViewModelFactory:

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

override fun <T : ViewModel?> create(modelClass: Class<T>): T {
    val creator = viewModels[modelClass]
        ?: viewModels.asIterable().firstOrNull {
            modelClass.isAssignableFrom(it.key)
        }?.value ?: throw IllegalArgumentException("$UNKNOWN_MODEL_CLASS $modelClass")
    return try {
        @Suppress("UNCHECKED_CAST")
        creator.get() as T
    } catch (e: Exception) {
        throw RuntimeException(e)
    }
}

}

When i change viewModels to Map it has following error:

public abstract interface AppComponent {
            ^
  java.util.Map<java.lang.Class<? extends androidx.lifecycle.ViewModel>,? extends javax.inject.Provider<androidx.lifecycle.ViewModel>> is injected at
      com.example.baseproject.utils.ViewModelFactory(viewModels)
  com.example.baseproject.utils.ViewModelFactory is injected at
      com.example.baseproject.di.ViewModelBuilder.bindViewModelFactory(viewModelFactory)
  androidx.lifecycle.ViewModelProvider.Factory is injected at
      com.example.baseproject.MainActivity.viewModelFactory
  com.example.baseproject.MainActivity is injected at
      dagger.android.AndroidInjector.inject(T) [com.example.baseproject.di.AppComponent → com.example.baseproject.di.ActivityModules_ContributeMainActivity.MainActivitySubcomponent]

Please help me i don't know why it's happening

Answer 1

You're missing a @JvmSuppressWildcards. You want to get a Provider<ViewModel>, not a Provider<? extends ViewModel>, but Kotlin would generate you a Provider<? extends ViewModel> without the annotation.

private val viewModels: Map<Class<out ViewModel>, @JvmSuppressWildcards Provider<ViewModel>>) : ViewModelProvider.Factory {