Swift - 告警提示框（UIAlertController）的用法

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()
    }
}

5，使用代码移除提示框

self .presentedViewController?.dismissViewControllerAnimated( false , completion:  nil )