Add view model

 1. Add lifecycle-extensions gradle dependency:

In the Module: app build.gradle file, add the lifecycle-extensions dependency. You can find the most current version of the dependency here.

implementation 'androidx.lifecycle:lifecycle-extensions:2.0.0' 

Don't forget to sync!

2. Create the GameViewModel class, extending ViewModel: Create a new file called GameViewModel.kt in the java/com.example.android.guesstheword/game package. Then in this file, create a class GameViewModel that extends ViewModel:

class GameViewModel : ViewModel()

3. Add init block and override onCleared. Add log statements to both:

Make an init block that prints out a log saying “GameViewModel created!”. Then override onCleared so you can track the lifetime of this ViewModel. You can use the keyboard shortcut Ctrl + O to do the override. Then add the log statement saying "GameViewModel destroyed!" to onCleared.

4.Create and initialize a GameViewModel, using ViewModelProviders. Add a log statement:

Back in GameFragment use lateinit to create a field for GameViewModel called viewModel. Then in onCreateView, request the current GameViewModel using the ViewModelProviders class:

viewModel = ViewModelProviders.of(this).get(GameViewModel::class.java)

Add a log statement before calling viewModel, saying "Called ViewModelProviders.of"