Creating a system overlay window (always on top)

Question

I\'m trying to create an always-op-top button/clickable-image which stays on top of all the windows all the time.

The proof of concept is

• here - Smar

Answer 1

Following @Sam Lu's answer, Indeed Android 4.x blocks certain types from listening to outside touch events, but some types, such as TYPE_SYSTEM_ALERT, still do the job.

Example

    WindowManager.LayoutParams params = new WindowManager.LayoutParams(
            WindowManager.LayoutParams.MATCH_PARENT,
            WindowManager.LayoutParams.MATCH_PARENT,
            WindowManager.LayoutParams.TYPE_SYSTEM_ALERT,
            WindowManager.LayoutParams.FLAG_NOT_FOCUSABLE
                    | WindowManager.LayoutParams.FLAG_NOT_TOUCH_MODAL
                    | WindowManager.LayoutParams.FLAG_WATCH_OUTSIDE_TOUCH,
            PixelFormat.TRANSLUCENT);

    WindowManager wm = (WindowManager) getSystemService(WINDOW_SERVICE);
    LayoutInflater inflater = (LayoutInflater) getSystemService(LAYOUT_INFLATER_SERVICE);
    View myView = inflater.inflate(R.layout.my_view, null);
    myView.setOnTouchListener(new OnTouchListener() {
       @Override
       public boolean onTouch(View v, MotionEvent event) {
           Log.d(TAG, "touch me");
           return true;
       }
     });

    // Add layout to window manager
    wm.addView(myView, params);

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