title: Swift how to use NSTimer background?
body: <pre><code>class ViewController: UIViewController {
  
      override func viewDidLoad() {
          super.viewDidLoad()
          var timer = NSTimer.scheduledTimerWithTimeInterval(1, target: self, selector:    Selector("update"), userInfo: nil, repeats: true)
      }
  
      func update() {
         println("Something cool")
      }
  }
  </code></pre>
  
  <p>It's ok for the Simulator ，I will get continuous "Something cool" through I tapped the home button. But it worked out when I debug the app with my iPhone. I did't get anything when I tapped the home button and make my app run background. 
  Someone told me I can play a long blank music to make my App run in the background.But I don't know how to play music in the background with swift @matt </p>