title: Programmatically disabling screenshot in App
body: <p>I want to prevent taking screenshot of a page in app. 
  how to do it programmatically so that screenshots cannot be taken.</p>
  
  <p>Found code to detect screenshot. Can it be deleted as soon as a screenshot is taken?</p>
  
  <pre><code>let mainQueue = NSOperationQueue.mainQueue()
  NSNotificationCenter.defaultCenter().addObserverForName(UIApplicationUserDidTakeScreenshotNotification,
      object: nil,
      queue: mainQueue) { notification in
          // executes after screenshot
  }
  </code></pre>