Application

Application.java

public class MyApp extends Application {
    public static boolean isAppInBackground = false;

    private Activity mCurrentActivity;


    public void onCreate() {
        super.onCreate();
        setScreenOrientation();
        this.mMyApp = (MyApp) getApplicationContext();
       
    }

    public Activity getCurrentActivity() {
        return this.mCurrentActivity;
    }

    public void setCurrentActivity(Activity mCurrentActivity) {
        this.mCurrentActivity = mCurrentActivity;
    }

    public void onTerminate() {
        super.onTerminate();
        
    }

    public void setScreenOrientation() {
        registerActivityLifecycleCallbacks(new ActivityLifecycleCallbacks() {
            public void onActivityCreated(Activity activity, Bundle savedInstanceState) {
                activity.setRequestedOrientation(1);
                activity.setTitle(MyApp.this.getResources().getString(R.string.app_name));
                MyApp.this.mMyApp.setCurrentActivity(activity);
                activity.getWindow().setSoftInputMode(3);
            }

            public void onActivityStarted(Activity activity) {
                MyApp.this.mMyApp.setCurrentActivity(activity);
            }

            public void onActivityResumed(Activity activity) {
                MyApp.this.mMyApp.setCurrentActivity(activity);
                MyApp.isAppInBackground = false;
            }

            public void onActivityPaused(Activity activity) {
                MyApp.isAppInBackground = true;
                MyApp.this.clearReferences();
            }

            public void onActivityStopped(Activity activity) {
            }

            public void onActivitySaveInstanceState(Activity activity, Bundle bundle) {
            }

            public void onActivityDestroyed(Activity activity) {
                MyApp.this.clearReferences();
            }
        });
    }

    private void clearReferences() {
        if (equals(this.mMyApp.getCurrentActivity())) {
            this.mMyApp.setCurrentActivity(null);
        }
    }
}