RelativeLayout rl_timer_to_send = (RelativeLayout) c.getWindow().findViewById(R.id.rl_timer_to_send);
rl_timer_to_send.setVisibility(View.VISIBLE);
rl_timer_to_send.setDrawingCacheEnabled(true);
Bitmap layer_timer = rl_timer_to_send.getDrawingCache();
float resizeTimerFactor = 851.0f / layer_timer.getWidth(); // java.lang.NullPointerException