Android - Remove fullscreen view added with addView

Question

I have a widget that trough an Intent calls to this activity that it's onCreate method has the following code:

WindowManager wm = (WindowManager) getApplicationContext().getSystemService(Context.WINDOW_SERVICE);
LayoutInflater inflater = (LayoutInflater) getSystemService(Context.LAYOUT_INFLATER_SERVICE);
mTopView = (ViewGroup) inflater.inflate(R.layout.screen_filter, null);

WindowManager.LayoutParams params = new WindowManager.LayoutParams(
                WindowManager.LayoutParams.FLAG_FULLSCREEN,
                WindowManager.LayoutParams.FLAG_FULLSCREEN,
                WindowManager.LayoutParams.TYPE_SYSTEM_OVERLAY,
                WindowManager.LayoutParams.FLAG_LAYOUT_IN_SCREEN,
                PixelFormat.TRANSLUCENT);           

        params.flags = WindowManager.LayoutParams.FLAG_LAYOUT_IN_SCREEN
                |WindowManager.LayoutParams.FLAG_NOT_TOUCHABLE
                | WindowManager.LayoutParams.FLAG_NOT_FOCUSABLE 
                |WindowManager.LayoutParams.FLAG_FULLSCREEN;

        getWindow().setAttributes(params);
        getWindow().clearFlags(WindowManager.LayoutParams.FLAG_FORCE_NOT_FULLSCREEN);
        getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN,
                WindowManager.LayoutParams.FLAG_FULLSCREEN);
        wm.addView(mTopView, params);

That code creates an overlay that acts as a screen filter staying on top of every activity.

Problem is that I don't know how to remove it later.

Calling to wm.removeView(mTopView); gives an error

java.lang.IllegalArgumentException: View not attached to window manager

From what I understand I lose the reference to that View I add since I call it from a widget using an Intent. It's a state machine, one state adds this view and following states is supposed to remove it.

How can I remove it? Maybe some method allows me to search for all the added views and then delete them?

Any hint would be appreciated.

Answer 1

Since your using the window manager to show the alert view , you need to keep the instance of the view added.

Create a service to add the view to window. So when the service is destroyed , you can remove the view from the window.

Here is a sample code ..

public class FloatingService extends Service {

private WindowManager windowManager;
private View floatingView;

WindowManager.LayoutParams params;
@Override
public IBinder onBind(Intent intent) {
    return null;
}

@Override
public int onStartCommand(Intent intent, int flag, int startId)
{
    // add window
    showAlert();
    return START_STICKY;
}

private void showAlert() {
    if(windowManager == null || floatingView == null) {
        windowManager = (WindowManager) getSystemService(WINDOW_SERVICE);
        floatingView = View.inflate(getBaseContext(),R.layout.floating_layout,null);
        // do your stuff to update the view in layout
        params = new WindowManager.LayoutParams(
                WindowManager.LayoutParams.WRAP_CONTENT,
                WindowManager.LayoutParams.WRAP_CONTENT,
                WindowManager.LayoutParams.TYPE_PHONE,
                WindowManager.LayoutParams.FLAG_NOT_FOCUSABLE,
                PixelFormat.TRANSLUCENT);
        params.gravity = Gravity.CENTER | Gravity.CENTER;
        windowManager.addView(floatingView, params);
    }
}

@Override
public void onCreate() {
    super.onCreate();
}

@Override
public void onDestroy() {
    super.onDestroy();
    if (floatingView != null) windowManager.removeView(floatingView);
}