Android Display Overlay

// setTargetSDK = 19

WindowManager wm = (WindowManager) getSystemService(Context.WINDOW_SERVICE);

        Button overlayedButton = new Button(this);
        overlayedButton.setText("Overlay button");
        overlayedButton.setOnTouchListener(this);
        overlayedButton.setAlpha(1);
        overlayedButton.setBackgroundColor(Color.BLACK);
        overlayedButton.setOnClickListener(this);

        WindowManager.LayoutParams params = new WindowManager.LayoutParams(WindowManager.LayoutParams.WRAP_CONTENT, WindowManager.LayoutParams.WRAP_CONTENT, WindowManager.LayoutParams.TYPE_SYSTEM_ALERT, WindowManager.LayoutParams.FLAG_NOT_FOCUSABLE | WindowManager.LayoutParams.FLAG_NOT_TOUCH_MODAL, PixelFormat.TRANSLUCENT);
        params.gravity = Gravity.LEFT | Gravity.TOP;
        params.x = 0;
        params.y = 0;
        wm.addView(overlayedButton, params);

        View  topLeftView = new View(this);
        WindowManager.LayoutParams topLeftParams = new WindowManager.LayoutParams(WindowManager.LayoutParams.WRAP_CONTENT, WindowManager.LayoutParams.WRAP_CONTENT, WindowManager.LayoutParams.TYPE_SYSTEM_ALERT, WindowManager.LayoutParams.FLAG_NOT_FOCUSABLE | WindowManager.LayoutParams.FLAG_NOT_TOUCH_MODAL, PixelFormat.TRANSLUCENT);
        topLeftParams.gravity = Gravity.LEFT | Gravity.TOP;
        topLeftParams.x = 0;
        topLeftParams.y = 0;
        topLeftParams.width = 0;
        topLeftParams.height = 0;
        wm.addView(topLeftView, topLeftParams);