title: How to add a view controller to window programmatically and bring it to front
body: <p><a href="https://i.stack.imgur.com/okISh.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/okISh.png" alt="enter image description here"></a>
  I want to do a screen saver for the whole app, but i only can do for 1 screen...now i am changing to appdelegate to start the timer and show the screen saver as a whole...However, i not sure how to add the video screen saver(video player view) as a whole at app delegate window... Timer i did edi, it really print out "Play Video" after 5 second, but the video view didn't show out.</p>
  
  <p>library used:
  1. <a href="https://github.com/piemonte/Player" rel="nofollow noreferrer">https://github.com/piemonte/Player</a>
  2. timer</p>