How to use a ViewModelProvider.Factory when extends from AndroidViewModel

Question

I want to send an extra parameter to my ViewModel, but this extends from AndroidViewModel. How can I add this parameter to the ViewModelFactory class ?

ViewModel

class ProjectViewModel(application: Application) : AndroidViewModel(application) {      // need a param for project id... } 

ViewModelFactory

class ProjectViewModelFactory(val projectId: Int): ViewModelProvider.Factory {      override fun <T : ViewModel?> create(modelClass: Class<T>): T {         // need to send this...         return ProjectViewModel(projectId) as T     } } 

Note: I notice that in the documentation its says: AndroidViewModel Subclasses must have a constructor which accepts Application as the only parameter.

So I don't know if it is posible (or good) to do what I'm trying to do.

Answer 1

Get ViewModel:

        viewModel = ViewModelProviders.of(this,                 new BListFactory(getActivity().getApplication(), 1))                 .get(BListViewModel.class); 

Factory:

class BListFactory extends ViewModelProvider.NewInstanceFactory {      @NonNull     private final Application application;      private final long id;      public BListFactory(@NonNull Application application, long id) {         this.application = application;         this.id = id;     }      @NonNull     @Override     public <T extends ViewModel> T create(@NonNull Class<T> modelClass) {         if (modelClass == BListViewModel.class) {             return (T) new BListViewModel(application, id);         }         return null;     } } 

AndroidViewModel:

public class BListViewModel extends AndroidViewModel {      private final long id;      public BListViewModel(@NonNull Application application, final long id) {         super(application);         this.id = id;     } }