Question

当我按如下方式键入代码时遇到问题，但出现错误？！

如果要在textFields上键入代码= 4234，然后点击“ ADD” =“ https://pastebin.com/raw/4234”，我要用户

@IBAction func btnPlusPressed(_ sender: UIButton)
{

    let alert = UIAlertController(title: "Provider M3U URL", message: "Add Provided URL to add you M3U Plailist", preferredStyle: .alert)
    let loginAction = UIAlertAction(title: "ADD", style: .default, handler: { (action) -> Void in

        var url = alert.textFields![0]

        if (url.text == "535" as String ){
            let strURLl : String = "https://pastebin.com/raw/\(url.text!)"

        }else{
            let strURLl : String = "\(url.text!)"
        }


        UserDefaults .standard .set(strURLl, forKey: "URL")

        let channelsVC = self.storyboard!.instantiateViewController(withIdentifier: "ChannelsViewController") as! ChannelsViewController
        channelsVC.strURL = strURLl!
        self.navigationController?.pushViewController(channelsVC, animated: true)

    })

为什么会出现这样的错误：（使用未解析的标识符'strURLl'）

Answer 1

在这里，您正在IF语句范围内定义常量strURLl。这意味着您只能在周围的{ }之外使用它

if (url.text == "535" as String ){
    let strURLl : String = "https://pastebin.com/raw/\(url.text!)"
} else {
    let strURLl : String = "\(url.text!)"
}

else语句也有问题。

解决方案

仅在IF范围之外声明常量

let strURLl: String
if (url.text == "535" as String ){
    strURLl = "https://pastebin.com/raw/\(url.text!)"
} else {
    strURLl = "\(url.text!)"
}

快速-无法使我的if语句正常运行

1 个答案:

解决方案