试试这个。 把波纹代码在按钮。

let alert = UIAlertController(title: "Your_Title_Text", message: "Your_MSG", preferredStyle: UIAlertControllerStyle.alert)
alert.addAction(UIAlertAction(title: "Your_Text", style: UIAlertActionStyle.default, handler: nil))
self.present(alert, animated:true, completion: nil)

如果你的目标是iOS 7和8，你需要这样的东西来确保你对每个版本都使用了正确的方法，因为UIAlertView在iOS 8中已弃用，但UIAlertController在iOS 7中不可用:

func alert(title: String, message: String) {
    if let getModernAlert: AnyClass = NSClassFromString("UIAlertController") { // iOS 8
        let myAlert: UIAlertController = UIAlertController(title: title, message: message, preferredStyle: .Alert)
        myAlert.addAction(UIAlertAction(title: "OK", style: .Default, handler: nil))
        self.presentViewController(myAlert, animated: true, completion: nil)
    } else { // iOS 7
        let alert: UIAlertView = UIAlertView()
        alert.delegate = self

        alert.title = title
        alert.message = message
        alert.addButtonWithTitle("OK")

        alert.show()
    }
}

使用此代码显示alertview

  let alertController = UIAlertController(title: "Hello  Coders", message: "your alert message", preferredStyle: .Alert)
        let defaultAction = UIAlertAction(title: "Close Alert", style: .Default, handler: nil)
        alertController.addAction(defaultAction)

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

Swift显示警报使用UIAlertController

一个按钮

class ViewController: UIViewController {

    @IBAction func showAlertButtonTapped(_ sender: UIButton) {

        // create the alert
        let alert = UIAlertController(title: "My Title", message: "This is my message.", preferredStyle: UIAlertController.Style.alert)

        // add an action (button)
        alert.addAction(UIAlertAction(title: "OK", style: UIAlertAction.Style.default, handler: nil))

        // show the alert
        self.present(alert, animated: true, completion: nil)
    }
}

两个按钮

class ViewController: UIViewController {

    @IBAction func showAlertButtonTapped(_ sender: UIButton) {

        // create the alert
        let alert = UIAlertController(title: "UIAlertController", message: "Would you like to continue learning how to use iOS alerts?", preferredStyle: UIAlertController.Style.alert)

        // add the actions (buttons)
        alert.addAction(UIAlertAction(title: "Continue", style: UIAlertAction.Style.default, handler: nil))
        alert.addAction(UIAlertAction(title: "Cancel", style: UIAlertAction.Style.cancel, handler: nil))

        // show the alert
        self.present(alert, animated: true, completion: nil)
    }
}

三个按钮

class ViewController: UIViewController {

    @IBAction func showAlertButtonTapped(_ sender: UIButton) {

        // create the alert
        let alert = UIAlertController(title: "Notice", message: "Lauching this missile will destroy the entire universe. Is this what you intended to do?", preferredStyle: UIAlertController.Style.alert)

        // add the actions (buttons)
        alert.addAction(UIAlertAction(title: "Remind Me Tomorrow", style: UIAlertAction.Style.default, handler: nil))
        alert.addAction(UIAlertAction(title: "Cancel", style: UIAlertAction.Style.cancel, handler: nil))
        alert.addAction(UIAlertAction(title: "Launch the Missile", style: UIAlertAction.Style.destructive, handler: nil))

        // show the alert
        self.present(alert, animated: true, completion: nil)
    }
}

处理按钮

在上面的例子中，处理程序为nil。当用户点击按钮时，你可以用一个闭包来替换nil。例如:

alert.addAction(UIAlertAction(title: "Launch the Missile", style: UIAlertAction.Style.destructive, handler: { action in

    // do something like...
    self.launchMissile()

}))

笔记

多个按钮不一定需要使用不同的UIAlertAction。风格类型。它们都可以是。default。 对于超过三个按钮，可以考虑使用动作表。设置非常相似。这里有一个例子。

斯威夫特3

下面是一个简单的例子，如何用Swift 3一个按钮创建一个简单的警报。

let alert = UIAlertController(title: "Title",
                              message: "Message",
                              preferredStyle: .alert)
alert.addAction(UIAlertAction(title: "Ok", style: .default))
present(alert, animated: true)

在上面的例子中，动作的句柄回调被省略了，因为带有一个按钮的警报视图的默认行为是在单击按钮时消失。

下面是如何创建另一个动作，可以用"alert. addaction (action)"添加到警报中。不同的样式是.default， .destructive和.cancel。

let action = UIAlertAction(title: "Ok", style: .default) { action in
    // Handle when button is clicked    
}

下面是警报视图和动作表的可重用代码，只需写一行在应用程序的任何地方显示警报

class AlertView{

    static func show(title:String? = nil,message:String?,preferredStyle: UIAlertControllerStyle = .alert,buttons:[String] = ["Ok"],completionHandler:@escaping (String)->Void){
        let alert = UIAlertController(title: title, message: message, preferredStyle: preferredStyle)

        for button in buttons{

            var style = UIAlertActionStyle.default
            let buttonText = button.lowercased().replacingOccurrences(of: " ", with: "")
            if buttonText == "cancel"{
                style = .cancel
            }
            let action = UIAlertAction(title: button, style: style) { (_) in
                completionHandler(button)
            }
            alert.addAction(action)
        }

        DispatchQueue.main.async {
            if let app = UIApplication.shared.delegate as? AppDelegate, let rootViewController = app.window?.rootViewController {
                rootViewController.present(alert, animated: true, completion: nil)
            }

        }
    }
}

用法:

class ViewController: UIViewController {

    override func viewWillAppear(_ animated: Bool) {
        AlertView.show(title: "Alert", message: "Are you sure ?", preferredStyle: .alert, buttons: ["Yes","No"]) { (button) in
            print(button)
        }
    }

}