public class MyApplication extends Application implements LifecycleObserver
{
    private static Context appContext;
    public static boolean wasInBackground;

    @Override
    public void onCreate()
    {
        super.onCreate();
        appContext=this;
        ProcessLifecycleOwner.get().getLifecycle().addObserver(this);
    }

    public static Context getAppContext() {
        return appContext;
    }

    @OnLifecycleEvent(Lifecycle.Event.ON_START)
    public void onMoveToForeground() {
        // app moved to foreground
        wasInBackground=true;
     }

    @OnLifecycleEvent(Lifecycle.Event.ON_STOP)
    public void onMoveToBackground() {
        // app moved to background
        wasInBackground =false;
    }
}