Ios/swift/AlertView

エラーメッセージ

       let alert = UIAlertView(title: "エラー", message: "エラーです", delegate: self, cancelButtonTitle: "OK")
       alert.show()

確認メッセージ

       let ac = UIAlertController(title: "Title", message: "Message", preferredStyle: .Alert)
       let cancelAction = UIAlertAction(title: "Cancel", style: .Cancel) { (action) -> Void in
           print("Cancel button tapped.")
       }
       let okAction = UIAlertAction(title: "OK", style: .Default) { (action) -> Void in
           print("OK button tapped.")
       }
       ac.addAction(cancelAction)
       ac.addAction(okAction)
       presentViewController(ac, animated: true, completion: nil)

参考：http://qiita.com/osamu1203/items/f1aea7b932e69522f638