title: User interface error on background processing (blinking parts of screen)
body: <p>I'm finishing an app which is integrated with an external device. This external device runs in a thread that can't be interrupted and I need to interact with the user through a view-animation, but sometimes the screen blinks and doesn't shows correctly.
  While the device is processing, the screen doesn't shows any changes on the user interface, made by the code. Then, I developed to perform these changes in background.</p>
  
  <p>I recorded this video to show what it happens, because when I took a print screen, it refreshes and works normally.</p>
  
  <p>What can I do to resolve this problem?</p>
  
  <p><a href="https://copy.com/LM2IVGi4F7zW" rel="nofollow">Video</a></p>
  
  <p>Thanks!</p>