Swift

1，下面代码创建并弹出一个告警框，并带有“取消”“确定”两个按钮

（注：自IOS8起，建议使用UIAlertController）

class ViewController: UIViewController{
    override func viewDidLoad() {
        super.viewDidLoad()
 
        var alertView = UIAlertView()
        alertView.title = "系统提示"
        alertView.message = "您确定要离开hangge.com吗？"
        alertView.addButtonWithTitle("取消")
        alertView.addButtonWithTitle("确定")
        alertView.cancelButtonIndex=0
        alertView.delegate=self;
        alertView.show()
    }
 
    func alertView(alertView:UIAlertView, clickedButtonAtIndex buttonIndex: Int){
        if(buttonIndex==alertView.cancelButtonIndex){
            println("点击了取消")
        }
        else
        {
            println("点击了确认")
        }
    }
}

2，告警框有下面4种样式
Default：默认样式
PlainTextInput：带输入框的告警框
SecureTextInput：带密码框的告警框
LoginAndPasswordInput：带输入框和密码框的告警框

下面是一个使用输入框和密码框的告警框样例：

import UIKit
 
class ViewController: UIViewController {
 
    var alertView = UIAlertView()
     
    override func viewDidLoad() {
        super.viewDidLoad()
         
        alertView.title = "系统登录"
        alertView.message = "请输入用户名和密码！"
        alertView.addButtonWithTitle("取消")
        alertView.addButtonWithTitle("确定")
        alertView.cancelButtonIndex=0
        alertView.delegate=self;
        alertView.alertViewStyle = UIAlertViewStyle.LoginAndPasswordInput
        alertView.show()
    }
     
    func alertView(alertView:UIAlertView, clickedButtonAtIndex buttonIndex: Int){
        if(buttonIndex==alertView.cancelButtonIndex){
            println("点击了取消")
        }
        else
        {
            let name = alertView.textFieldAtIndex(0)
            let password = alertView.textFieldAtIndex(1)
            println("用户名是：(name!.text) 密码是：(password!.text)")
        }
    }
 
    override func didReceiveMemoryWarning() {
        super.didReceiveMemoryWarning()
    }
}