課題0の例

0-0.java

public class MainActivity extends AppCompatActivity {
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        …
        final LifecycleObserver lifecycleObserver = new LifecycleObserver() {
            @OnLifecycleEvent(Lifecycle.Event.ON_ANY)
            public void calledWhenOnAny(LifecycleOwner source, Lifecycle.Event event) {
                Log.d("CODELAB", "Lifecycle state:" + source.getLifecycle().getCurrentState().name());
            }
        };
        getLifecycle().addObserver(lifecycleObserver);
    }
}