title: Swift showing use of Unresolved Identifier 'UIAlertController'
body: <pre><code>import Cocoa
  
  class ViewController: NSViewController {
  
      @IBOutlet weak var helloButton: NSButton!
      @IBAction func showAlert(sender: AnyObject) {
  
          var alert = UIAlertController(title: "Hello!", message: "Hello, world!",
          preferredStyle: UIAlertControllerStyle.Alert)
          alert.addAction(UIAlertAction(title: "Close", style: UIAlertActionStyle.Default, handler: nil))
          self.presentViewController(alert, animated: true, completion: nil)
          self.helloButton.setTitle("Clicked", forState: UIControlState.Normal)
      }
  </code></pre>