如何在Swift（iOS 7）中为UIAlertView添加动作

Question

我想为“重试”按钮添加一个操作，但当用户按下“重试”按钮时没有任何反应。

var createAccountErrorAlert: UIAlertView = UIAlertView()

createAccountErrorAlert.delegate = self                

createAccountErrorAlert.title = "Oops"
createAccountErrorAlert.message = "Could not create account!"
createAccountErrorAlert.addButtonWithTitle("Dismiss")
createAccountErrorAlert.addButtonWithTitle("Retry")

createAccountErrorAlert.show()

确定按下按钮的索引函数？

func alertView(View: UIAlertView!, clickedButtonAtIndex buttonIndex: Int){

    switch buttonIndex{

    case 1:
        createAccount()

    default:
        //Some code here..

    }
}

- Stephen Fox

---

你尝试过如何调试这个问题吗？你是否在函数内设置了断点以查看它是否触发？你是否添加了日志语句以查看 buttonIndex 是什么？这些是我需要做的第一件事情，以便复制你遇到的错误。 - wjl

Answer 1

我测试了你的代码，它对我来说运行良好，打印出相应的结果：

func showAlert(){
    var createAccountErrorAlert: UIAlertView = UIAlertView()

    createAccountErrorAlert.delegate = self

    createAccountErrorAlert.title = "Oops"
    createAccountErrorAlert.message = "Could not create account!"
    createAccountErrorAlert.addButtonWithTitle("Dismiss")
    createAccountErrorAlert.addButtonWithTitle("Retry")

    createAccountErrorAlert.show()
}

func alertView(View: UIAlertView!, clickedButtonAtIndex buttonIndex: Int){

    switch buttonIndex{

    case 1:
        NSLog("Retry");
    break;
    case 0:
        NSLog("Dismiss");
        break;
    default:
        NSLog("Default");
        break;
        //Some code here..

    }
}

当我点击关闭按钮时，它会打印出 dismiss。

- Saurav Nagpal

---

对于那些可能遇到问题的人：如果您使用“var createAccountErrorAlert= UIAlertView()”，它将无法正常工作。 - kommradHomer

Answer 2

这是我用更短的代码行完成的方法：

func showAlert(){
    var alert = UIAlertView(title: "Choose", message: "Which_pill", delegate: self, cancelButtonTitle:"Red")
    alert.addButtonWithTitle("Blue")
    alert.show()
}

func alertView(View: UIAlertView!, clickedButtonAtIndex buttonIndex: Int){
    switch buttonIndex{
    case 1: println("Blue")
    case 0: println("Red")
    default: println("Is this part even possible?")
    }
}

- Esqarrouth

Answer 3

这是因为您的重试按钮的索引是1，而不是0。关闭按钮的索引是0。

如果您将以下代码放入播放器中，您实际上会看到按钮的索引（如addButtonWithTitle方法中所记录的）。

var createAccountErrorAlert: UIAlertView = UIAlertView()
createAccountErrorAlert.title = "Oops"
createAccountErrorAlert.message = "Could not create account!"
createAccountErrorAlert.addButtonWithTitle("Dismiss") //Prints 0
createAccountErrorAlert.addButtonWithTitle("Retry") //Prints 1

- Mike Seghers

---

当我尝试您的代码时，它确实起作用。您能否在createAccount()方法中发送代码？或者尝试@wjl建议的，在委托方法中设置断点，并检查索引值。或者在委托方法中放置"println(buttonIndex)"，并查看在点击重试按钮时控制台上打印的内容。 - Mike Seghers

Answer 4

索引错误。以下代码（基于iOS单视图默认应用程序模板）适用于我（我将按钮连接到触发@IBAction buttonPressed）。不要忘记将您的视图控制器设置为UIAlertViewDelegate（尽管以下代码无需这样做）：

import UIKit

class ViewController: UIViewController, UIAlertViewDelegate {

    override func viewDidLoad() {
        super.viewDidLoad()
        // Do any additional setup after loading the view, typically from a nib.
    }

    override func didReceiveMemoryWarning() {
        super.didReceiveMemoryWarning()
        // Dispose of any resources that can be recreated.
    }

    @IBAction func buttonPressed(sender : AnyObject) {
        var createAccountErrorAlert: UIAlertView = UIAlertView()

        createAccountErrorAlert.delegate = self

        createAccountErrorAlert.title = "Oops"
        createAccountErrorAlert.message = "Could not create account!"
        createAccountErrorAlert.addButtonWithTitle("Dismiss")
        createAccountErrorAlert.addButtonWithTitle("Retry")

        createAccountErrorAlert.show()
    }

    func alertView(View: UIAlertView!, clickedButtonAtIndex buttonIndex: Int) {

        switch buttonIndex {

        default:
            println("alertView \(buttonIndex) clicked")

        }
    }
}

- JefferyRPrice