四步曲：

1、创建UIAlertController 警告控制器

2、创建UIAlertAction 警告行为

3、将UIAlertAction 添加到UIAlertController

4、present出UIAlertController 警告控制器

直接上代码

import@H_502_49@ UIKit

@H_502_49@

class@H_502_49@ ViewController: UIViewController@H_502_49@ {

@H_502_49@

var controller:@H_502_49@UIAlertController?

@H_502_49@

@H_502_49@ override@H_502_49@ func@H_502_49@ viewDidLoad() {

super.@H_502_49@viewDidLoad()

@H_502_49@

@H_502_49@controller = @H_502_49@UIAlertController(

title: @H_502_49@"Choose how you would like to share this photo",

message: @H_502_49@"You cannot bring back a deleted photo",

@H_502_49@ preferredStyle: .ActionSheet@H_502_49@)

@H_502_49@

@H_502_49@ let@H_502_49@ actionEmail = UIAlertAction@H_502_49@(title: "Via email"@H_502_49@,

style: @H_502_49@UIAlertActionStyle.@H_502_49@Default,

@H_502_49@ handler: {(paramAction:UIAlertAction@H_502_49@!) in

@H_502_49@/* Send the photo via email */

@H_502_49@ })

@H_502_49@

@H_502_49@ let@H_502_49@ actionImessage = UIAlertAction@H_502_49@(title: "Via iMessage"@H_502_49@,0)"> @H_502_49@/* Send the photo via iMessage */

@H_502_49@ })

@H_502_49@

@H_502_49@ let@H_502_49@ actionDelete = UIAlertAction@H_502_49@(title: "Delete photo"@H_502_49@,175)"> style: @H_502_49@UIAlertActionStyle.@H_502_49@Destructive,0)"> @H_502_49@/* Delete the photo here */

@H_502_49@ })

@H_502_49@

@H_502_49@ controller@H_502_49@!.addAction@H_502_49@(actionEmail)

@H_502_49@ controller@H_502_49@!.addAction@H_502_49@(actionImessage)

@H_502_49@ controller@H_502_49@!.addAction@H_502_49@(actionDelete)

@H_502_49@

@H_502_49@ }

@H_502_49@

@H_502_49@ override@H_502_49@ func@H_502_49@ viewDidAppear(animated: Bool@H_502_49@) {

@H_502_49@ super@H_502_49@.viewDidAppear@H_502_49@(animated)

@H_502_49@ self@H_502_49@.presentViewController@H_502_49@(controller@H_502_49@!,animated: true@H_502_49@,completion: nil@H_502_49@)

@H_502_49@ }

@H_502_49@

@H_502_49@}