fhhvvjct@tg says to 鑑賞彼特台
@IBAction func showMessage(sender: UIButton) { let alertController = UIAlertController(title: "Welcome to My First App", message: "Hello World", preferredStyle: UIAlertController.Style.alert) alertController.addAction(UIAlertAction(title: "OK", style: UIAlertAction.Style.default, handler: nil)) present(alertController, animated: true, completion: nil) } 😱