swift AlertView

 let alertView = UIAlertView()
                alertView.title = "系统提示"
                alertView.message = "现在不是Wifi网络,您确定要下载吗？"
                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){
        }
        else
        {
            if isSaveLocal() {
                hudShowWithTextOnly("视频已存在下载列表")
                return
            }
            if  modelVo != nil && !downBtnStatus {
                addDownloadVideo()
            }
        }
    }