App Widget with ViewModel and Lifecycleowner

Question

I use MVVM in my project. But when i create App Widget he does not support LifecycleOwner in updateAppWidget()

var model: CurrencyViewModel
model = ViewModelProvider(this).get(CurrencyViewModel::class.java)

Do I have a chance to access the model from App Widget?

Answer 1

That's not what the ViewModelProvider is meant for. When the widget is running the activity might be destroyed together with it's ViewModels. The AppWidgetProvider itself doesn't really have a lifecycle.

If you want to get data from the App into the App Widget you should save it in SharedPreferences or a database.

/**
     * Creates a {@link ViewModelProvider}, which retains ViewModels while a scope of given Activity
     * is alive. More detailed explanation is in {@link ViewModel}.
     * <p>
     * It uses the {@link FragmentActivity#getDefaultViewModelProviderFactory() default factory}
     * to instantiate new ViewModels.
     *
     * @param activity an activity, in whose scope ViewModels should be retained
     * @return a ViewModelProvider instance
     * @deprecated Use the 'by viewModels()' Kotlin property delegate or
     * {@link ViewModelProvider#ViewModelProvider(ViewModelStoreOwner)},
     * passing in the activity.
     */
    @Deprecated
    @NonNull
    @MainThread
    public static ViewModelProvider of(@NonNull FragmentActivity activity) {
        return new ViewModelProvider(activity);
    }