学习笔记：swift——下方弹窗事件UIAlertControl

var alert: UIAlertController!
        alert = UIAlertController(title: "设为离开模式？", message: "", preferredStyle: UIAlertControllerStyle.ActionSheet)
        let cleanAction = UIAlertAction(title: "取消", style: UIAlertActionStyle.Cancel, handler: nil)
        let photoAction = UIAlertAction(title: "拍照", style: UIAlertActionStyle.Default, handler: nil)
        let choseAction = UIAlertAction(title: "从手机相册选择", style: UIAlertActionStyle.Default, handler: {action in self.buttonclick()})
        let videoAction = UIAlertAction(title: "小视频", style: UIAlertActionStyle.Default, handler: nil)
     
        alert.addAction(cleanAction)
        alert.addAction(photoAction)
        alert.addAction(choseAction)
        alert.addAction(videoAction)

        self.presentViewController(alert, animated: true, completion: nil)