标签: uialertcontroller

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)
        }
    })
}

我已经写代码,出现报警时,在我的UITextFields的一个输入小于1050中输入满足这一点,但我后按"确定"它会立即重新出现时出现成功.

下面是viewDidLoad函数中的代码:

override func viewDidLoad(){
    super.viewDidLoad()
    alert = UIAlertController(title: "Error", message: "Please enter an exit width value greater than 1050", preferredStyle: UIAlertControllerStyle.Alert)
    let okay = UIAlertAction(title: "OK", style: UIAlertActionStyle.Destructive, handler: valueCalc)
    alert.addAction(okay)
}

然后我有我的valueCalc功能(当点击按钮时调用):

@IBAction func valueCalc(sender: AnyObject){
    if(Int(mmText.text!)! < 1050){ //mmText is an UITextField
        self.presentViewController(alert, animated: true, completion: nil)
    }
}

我的iOS应用程序需要一组具有类似功能的自定义警报.我可以将它们打包在一个类中,所以我不必在每个UIViewController中复制粘贴吗？

func displayAlert(msg:String, handler: (UIAlertAction) -> Void?{...} 
func successMsg (msg: String){...}  
func failMsg(msg: String){...}

我试图将它们打包到UIViewController的子类(AlertViewController)中,但之后出现了运行时错误:"尝试在<... UIAlertController ...>上显示<... UIAlertController ...>,其视图不在窗口层层叠叠!"

myViewController中的代码:

@IBAction func leave() {
    let date = getDate()
    let datePresent = dateForPresent()
    if stID == nil || name == nil {
        return
    } else {
        alert.displayAlert("\(datePresent)"){action in
            self.request.getResult(self.request.leavePara(self.stID!, date: date, name: self.name!) ){ (result) in
                dispatch_async(dispatch_get_main_queue(), {
                    let flag = result["result","out_Flag"].int
                    print(result)
                    let msg = result["result","out_nszRtn"].string!
                    if flag == 0 {
                        self.alert.successMsg(msg){ action in
                            self.performSegueWithIdentifier("personUnwind", sender: self)
                        }
                    }else { …

我有一个场景，可能需要重命名某些内容，我想用它UIAlertController来收集新名称。我希望它能够同时进行多次更改（虽然不太可能，但我想支持它）。

问题是我只需要在当前的结果出现时循环才能继续UIAlertController，事实上，循环会立即继续，当然一次不能出现多个。我一整天都被困在这个问题上，需要帮助。

我需要某种使用完成处理程序为下一个循环迭代提供绿灯的方法。

这是问题的简化版本，changeNames 函数位于UIViewController.

var names = ["Bob","Kate"]

func changeNames(){
    for name in names {
        let alert = UIAlertController(title: "Rename \(name)",
                                      message: "What would you like to call \(name)?",
                                      preferredStyle: .alert)
        alert.addTextField(configurationHandler: { (textField) in
            textField.text = name
        })
        alert.addAction(UIAlertAction(title: "OK", style: .default, handler: { [weak alert] (_) in
            print("User changed \(name) to \(alert!.textFields![0].text)")
            //Don't continue the loop until now
        }))
        self.present(alert, animated: true)
    }
}

谢谢

我面临如下问题,它发生在iOS 10.x中

let alertController = UIAlertController(title: nil, message: nil, preferredStyle: .actionSheet)
        alertController.popoverPresentationController?.sourceView = label
        alertController.popoverPresentationController?.sourceRect = label.bounds

        let action1 = UIAlertAction(title:"test", style: .default) { [weak self] _ in
        }

        let action2 = UIAlertAction(title:"test" style: .default) { [weak self] _ in
        }
 alertController.addAction(action1)
 alertController.addAction(action2)


        present(alertController, animated: true, completion: nil)

当我打开这个带有标签点击的警报控制器时,我看到我的alertcontroller作为附加屏幕.它的按钮不可见.

2018-02-10 23:13:16.814325 Project[27392:1655456] [LayoutConstraints] Unable to simultaneously satisfy constraints.
    Probably at least one of the constraints in the following list is one you don't want. 
    Try this: 
        (1) look at each …