title: How can I keep playing the UILocalNotification sound until user dismiss it?
body: <p>As titled, I use <code>UILocalNotification</code> for alarm purposes. But the sound is only played once. </p>
  
  <p>I would like to keep the sound playing until user dismisses the notification. Is that possible?</p>
  
  <p>Please post some sample code if that's possible.</p>
  
  <p>Multiple notification certainly can do it, but I want to keep the notification center neat.  </p>