How to Implement ViewModel Factory in Android

Question

I am implementing Room database with ViewModel. Everything works well. But the requirement is I want to provide some dependency to ViewModel using AndroidViewModelFactory. I am able to create ViewModelFactory class which implements ViewModelProvider.Factory. I am passing a normal String as a dependency to ViewModel. The code for Factory class is

public class TestViewModelFactory  implements ViewModelProvider.Factory{
    private static final String DEFAULT_LIMIT = "4";
    static Application application;
    static String created="ViewModelFactorySuccess";

    public static TestViewModelFactory createFactory(Activity activity) {
        application = activity.getApplication();
        if (application == null) {
            throw new IllegalStateException("Not yet attached to Application");
        }
        return new TestViewModelFactory(application, created);
    }
    public TestViewModelFactory(Application application, String created) {
        application=application;
        created=created;

    }
    @NonNull
    @Override
    public <T extends ViewModel> T create(@NonNull Class<T> modelClass) {
        try {
            return modelClass.getConstructor(TestViewModel.class, int.class)
                    .newInstance(application, created);
        } catch (NoSuchMethodException | IllegalAccessException |
                InstantiationException | InvocationTargetException e) {
            throw new RuntimeException("Cannot create an instance of " + modelClass, e);
        }
    }
}  

In MainActivity the normal instance of ViewModel is created as

TestViewModel testViewModel=new ViewModelProvider.AndroidViewModelFactory(getApplication()).create(TestViewModel.class);  

which is working fine. But how to create a instance of ViewModel factory class so that a dependency can be provided to ViewModel.Please suggest the correct approach for ViewModel instance creation. Any help would be appreciated.

Answer 1

Generic Example (up to android.arch.lifecycle:extensions:1.1.0). it is deprecated from 1.1.1,

MyViewModel myViewModel = new ViewModelProviders.of(this, new MyViewModelFactory(this.getApplication(), "Your string parameter")).get(MyViewModel.class);

Generic Example (for android.arch.lifecycle:extensions:1.1.1)

MyViewModel myViewModel = new ViewModelProvider(this, viewModelFactory).get(MyViewModel.class);

OR, Use ViewModelStore link

MyViewModel myViewModel = new ViewModelProvider(getViewModelStore(), viewModelFactory).get(MyViewModel.class);