Swift - 告警提示框（UIAlertController）的用法-优快云博客

本文介绍如何使用 UIAlertController 来创建各种类型的提示框，包括简单的警告框、带文本输入的登录框等，并展示了如何调整样式和处理用户输入。

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自iOS8起，苹果就建议告警框使用UIAlertController来代替UIAlertView。下面总结了一些常见的用法：

1，简单的应用（同时按钮响应Handler使用闭包函数）

import UIKit
 
class ViewController: UIViewController ,UIActionSheetDelegate {
    override func viewDidLoad() {
        super.viewDidLoad()
    }
     
    override func viewDidAppear(animated: Bool){
        super.viewDidAppear(animated)
         
        let alertController = UIAlertController(title: "系统提示",
            message: "您确定要离开hangge.com吗？", preferredStyle: UIAlertControllerStyle.Alert)
        let cancelAction = UIAlertAction(title: "取消", style: UIAlertActionStyle.Cancel, handler: nil)
        let okAction = UIAlertAction(title: "好的", style: UIAlertActionStyle.Default,
            handler: {
                action in
                print("点击了确定")
        })
        alertController.addAction(cancelAction)
        alertController.addAction(okAction)
        self.presentViewController(alertController, animated: true, completion: nil)
    }
     
    override func didReceiveMemoryWarning() {
        super.didReceiveMemoryWarning()
        // Dispose of any resources that can be recreated.
    }
}

2，除了弹出，还可以使用从底部向上滑出的样式
（注意：如果上拉菜单中有“取消”按钮的话，那么它永远都会出现在菜单的底部，不管添加的次序是如何）

var alertController = UIAlertController(title: "保存或删除数据", message: "删除数据将不可恢复",
    preferredStyle: UIAlertControllerStyle.ActionSheet)
var cancelAction = UIAlertAction(title: "取消", style: UIAlertActionStyle.Cancel, handler: nil)
var deleteAction = UIAlertAction(title: "删除", style: UIAlertActionStyle.Destructive, handler: nil)
var archiveAction = UIAlertAction(title: "保存", style: UIAlertActionStyle.Default, handler: nil)
alertController.addAction(cancelAction)
alertController.addAction(deleteAction)
alertController.addAction(archiveAction)
self.presentViewController(alertController, animated: true, completion: nil)

3，按钮使用“告警”样式（文字颜色变红，用来来警示用户）

var okAction = UIAlertAction(title: "好的", style: UIAlertActionStyle.Destructive, handler: nil)

4，添加任意数量文本输入框（比如可以用来实现个登陆框）

import UIKit
 
class ViewController: UIViewController ,UIActionSheetDelegate {
    override func viewDidLoad() {
        super.viewDidLoad()
    }
     
    override func viewDidAppear(animated: Bool){
        super.viewDidAppear(animated)
         
        let alertController = UIAlertController(title: "系统登录",
            message: "请输入用户名和密码", preferredStyle: UIAlertControllerStyle.Alert)
        alertController.addTextFieldWithConfigurationHandler {
            (textField: UITextField!) -> Void in
            textField.placeholder = "用户名"
        }
        alertController.addTextFieldWithConfigurationHandler {
            (textField: UITextField!) -> Void in
            textField.placeholder = "密码"
            textField.secureTextEntry = true
        }
        let cancelAction = UIAlertAction(title: "取消", style: UIAlertActionStyle.Cancel, handler: nil)
        let okAction = UIAlertAction(title: "好的", style: UIAlertActionStyle.Default,
            handler: {
                action in
                let login = alertController.textFields!.first! as UITextField
                let password = alertController.textFields!.last! as UITextField
                print("用户名：\(login.text) 密码：\(password.text)")
        })
        alertController.addAction(cancelAction)
        alertController.addAction(okAction)
        self.presentViewController(alertController, animated: true, completion: nil)
    }
     
    override func didReceiveMemoryWarning() {
        super.didReceiveMemoryWarning()
    }
}