iOS Swift：在显示警报确认消息的函数中返回“Bool”

Question

我正在创建一个返回布尔值的函数。但是 Swift 向我展示了错误：

预期返回“Bool”的函数中缺少返回值

我的函数不直接返回“布尔”，它有一些条件，比如如果用户点击“确定”按钮，那么它应该返回真，如果“取消”则返回假。有人可以告诉我如何解决这个问题吗？请参阅以下代码以供参考：

func showConfirmationAlert(title: String!, message: String!) -> Bool {
    dispatch_async(dispatch_get_main_queue(), {
        let alertController=UIAlertController(title: title, message: message, preferredStyle: UIAlertControllerStyle.Alert)
        let okButton=UIAlertAction(title: "Ok", style: UIAlertActionStyle.Default) { (okSelected) -> Void in
            return true
        }
        let cancelButton=UIAlertAction(title: "Cancel", style: UIAlertActionStyle.Cancel) { (cancelSelected) -> Void in
            return false
        }
        alertController.addAction(okButton)
        alertController.addAction(cancelButton)
        if self.presentedViewController == nil {
            self.presentViewController(alertController, animated: true, completion: nil)
        }
    })
}

Answer 1

认为你想要这样的东西

func showConfirmationAlert(title: String!, message: String!,success: (() -> Void)? , cancel: (() -> Void)?) {
  dispatch_async(dispatch_get_main_queue(), {
  let alertController = UIAlertController(title:title,
    message: message,
    preferredStyle: UIAlertControllerStyle.Alert)

  let cancelLocalized = NSLocalizedString("cancelButton", tableName: "activity", comment:"")
  let okLocalized = NSLocalizedString("viewDetails.button", tableName: "Localizable", comment:"")

  let cancelAction: UIAlertAction = UIAlertAction(title: cancelLocalized,
    style: .Cancel) {
      action -> Void in cancel?()
  }
  let successAction: UIAlertAction = UIAlertAction(title: okLocalized,
    style: .Default) {
      action -> Void in success?()
  }
    alertController.addAction(cancelAction)
    alertController.addAction(successAction)

    self.presentViewController(alertController, animated: true, completion: nil)
  })
}
showConfirmationAlert("mytitle", message: "body", success: { () -> Void in
  print("success")
  }) { () -> Void in
    print("user canceled")
}