Sample usage of the "android.app.Application.ActivityLifecycleCallbacks" class.

MainActivity.java

public class MainActivity extends Activity {

  private final MyActivityLifecycleCallbacks mCallbacks = new MyActivityLifecycleCallbacks();

  @Override
  protected void onCreate(Bundle savedInstanceState) {
    // Always register before calling into the super class.
    getApplication().registerActivityLifecycleCallbacks(mCallbacks);
    
    super.onCreate(savedInstanceState);
  }

  @Override
  protected void onDestroy() {
    super.onDestroy();

    // Always unregister after calling into the super class.
    getApplication().unregisterActivityLifecycleCallbacks(mCallbacks);
  }

  public static class MyActivityLifecycleCallbacks implements ActivityLifecycleCallbacks {

    @Override
    public void onActivityCreated(Activity activity, Bundle savedInstanceState) {
      Log.i(activity.getClass().getSimpleName(), "onCreate(Bundle)");
    }

    @Override
    public void onActivityStarted(Activity activity) {
      Log.i(activity.getClass().getSimpleName(), "onStart()");
    }

    @Override
    public void onActivityResumed(Activity activity) {
      Log.i(activity.getClass().getSimpleName(), "onResume()");
    }

    @Override
    public void onActivityPaused(Activity activity) {
      Log.i(activity.getClass().getSimpleName(), "onPause()");
    }

    @Override
    public void onActivitySaveInstanceState(Activity activity, Bundle outState) {
      Log.i(activity.getClass().getSimpleName(), "onSaveInstanceState(Bundle)");
    }

    @Override
    public void onActivityStopped(Activity activity) {
      Log.i(activity.getClass().getSimpleName(), "onStop()");
    }

    @Override
    public void onActivityDestroyed(Activity activity) {
      Log.i(activity.getClass().getSimpleName(), "onDestroy()");
    }
  }
}

For what it's worth, I created a variant of this with a couple of tweaks:

• The callback un-registers itself, thereby simplifying usage.
• The callback knows which activity it was registered for, and ignores all others. (The callback is invoked for all activities, not just the one where we registered it.)

That was useful to me, thanks!

Thank you so much!