不要在构造函数中提供otherbuttontitle。

let alertView = UIAlertView(title: "Oops!", message: "Something
happened...", delegate: nil, cancelButtonTitle: "OK")

alertView.show()

但我同意Oscar的观点，这个类在iOS 8中被弃用了，所以如果你只做iOS 8的应用程序，UIAlertView不会没有任何用途。否则上面的代码将工作。

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    
}

Swift 5上的SwiftUI。x和Xcode 11.x

import SwiftUI

struct ContentView: View {

    @State private var isShowingAlert = false

    var body: some View {
        VStack {
            Button("A Button") {

                self.isShowingAlert.toggle()
            }
            .alert(isPresented: $isShowingAlert) { () -> Alert in
                Alert(
                    title: Text("Alert"),
                    message: Text("This is an alert"),
                    dismissButton:
                        .default(
                            Text("OK"),
                            action: {
                                print("Dismissing alert")
                            }
                        )
                )
            }

        }
        .padding()
    }
}

struct ContentView_Previews: PreviewProvider {
    static var previews: some View {
        ContentView()
    }
}

// UIAlertView的自定义类

//MARK:- MODULES
import Foundation
import UIKit

//MARK:- CLASS
class Alert  : NSObject{

static let shared = Alert()

var okAction : AlertSuccess?
typealias AlertSuccess = (()->())?
var alert: UIAlertController?

/** show */
public func show(title : String?, message : String?, viewController : UIViewController?, okAction : AlertSuccess = nil) {

    let version : NSString = UIDevice.current.systemVersion as NSString
    if  version.doubleValue >= 8 {
        alert = UIAlertController(title: title, message: message, preferredStyle:.alert)
        alert?.addAction(UIAlertAction(title: "OK", style: .default, handler: { (action: UIAlertAction) in

            if let okAction = okAction {
                okAction()
            }
        }))
        viewController?.present(alert ?? UIAlertController(), animated:true, completion:nil);
    }
}

/** showWithCancelAndOk */
public func showWithCancelAndOk(title : String, okTitle : String, cancelTitle : String, message : String, viewController : UIViewController?, okAction : AlertSuccess = nil, cancelAction : AlertSuccess = nil) {
    let version:NSString = UIDevice.current.systemVersion as NSString;

    if  version.doubleValue >= 8 {
        alert = UIAlertController(title: title, message: message, preferredStyle:.alert)

        alert?.addAction(UIAlertAction(title: cancelTitle, style: .default, handler: { (action: UIAlertAction) in

            if let cancelAction = cancelAction {
                cancelAction()
            }
        }))
        alert?.addAction(UIAlertAction(title: okTitle, style: .default, handler: { (action: UIAlertAction) in

            if let okAction = okAction {
                okAction()
            }
        }))
        viewController?.present(alert!, animated:true, completion:nil);
    }
}

/** showWithTimer */
public func showWithTimer(message : String?, viewController : UIViewController?) {

    let version : NSString = UIDevice.current.systemVersion as NSString
    if  version.doubleValue >= 8 {
        alert = UIAlertController(title: "", message: message, preferredStyle:.alert)
        viewController?.present(alert ?? UIAlertController(), animated:true, completion:nil)
        let when = DispatchTime.now() + 1
        DispatchQueue.main.asyncAfter(deadline: when){
            self.alert?.dismiss(animated: true, completion: nil)
        }
    }
}
}

使用:

Alert.shared.show(title: "No Internet Connection", message: "The internet connection appers to be offline.", viewController: self) //without ok action

Alert.shared.show(title: "No Internet Connection", message: "The internet connection appers to be offline.", viewController: self, okAction: {
                            //ok action
                        }) // with ok action

Alert.shared.show(title: "No Internet Connection", message: "The internet connection appers to be offline.", viewController: self, okAction: {
                            //ok action 
}, cancelAction: {
 //cancel action
}) //with cancel and ok action

Alert.shared.showWithTimer(message : "This is an alert with timer", viewController : self) //with timer

你可以使用标准的构造函数创建一个UIAlert，但是“遗留的”构造函数似乎不起作用:

let alert = UIAlertView()
alert.title = "Alert"
alert.message = "Here's a message"
alert.addButtonWithTitle("Understood")
alert.show()

AlertView Swift 5及以上:-

let alert = UIAlertController(title: LocalizedStringConstant.alert, message: message, preferredStyle: UIAlertController.Style.alert)
alert.addAction(UIAlertAction(title: "Retry", style: .cancel, handler: { (_) in
     }))
self.present(alert, animated: true, completion: nil)