Chapter 20 Challenge 2

[jpaone]

Following the ViewModel and ViewModelFactory paradigm

Solution to Deprecated method ViewModelProviders#of

Here is a better argument for using the Factory model. Consider Listing 4.6 where we make currentIndex public so we can access and assign its value via the Bundle. // Listing 4.6 - QuizViewModel.kt class QuizViewModel : ViewModel() { var currentIndex = 0 ... } This is now used in Listing 4.11 // Listing 4.11 - MainActivity.kt override fun onSaveInstanceState(savedInstanceState: Bundle) { super.onSaveInstanceState(savedInstanceState) Log.i(TAG, "onSaveInstanceState") savedInstanceSt…

this works when creating a Jetpack ViewModel. You’ll want to set up the following classes:

BeatBoxViewModel that accepts an AssetManager as a constructor argument. The class then has a public instance of BeatBox. Override the onCleared() method to release the sound pool.

BeatBoxViewModelFactory that accepts an AssetManager as a constructor argument. Override the create() method to create an instance of BeatBoxViewModel.

Now in MainActivity, create the factory and beatBoxViewModel objects. Anywhere that beatBox was referenced now replace it with beatBoxViewModel.beatBox. We will want to remove the onDestroy() overridden method to not release the sound pool when the activity is destroyed.