“条件绑定的初始化程序必须具有可选类型，而不是'[String：Any]'” swift中的错误

Question

这是出现错误的函数。

func LoadMapRoute(Url:String)
        {


            let url = URL(string: Url)

            let session = URLSession(configuration: .default)
            let task = session.dataTask(with: url!, completionHandler: {
                (data, response, error) in

                guard error == nil else {
                    print(error!.localizedDescription)
                    return
                }

                guard let jsonResult = try? (JSONSerialization.jsonObject(with: data!, options: .allowFragments) as? [String: Any]),
                    let jsonResponse = jsonResult else {
                    print("error in JSONSerialization")
                    return
                }

                //Call this method to draw path on map
                self.drawPath(from: polyLineString)
            })
            task.resume()
        }

这是在 guard let = jsonResult 中显示错误的那一行

  let jsonResponse = jsonResult

Answer 1

请参考以下代码：

 guard let jsonResult = try? JSONSerialization.jsonObject(with: data!, options: .allowFragments),let jsonResponse = jsonResult  as? [String: Any] else {
      print("error in JSONSerialization")
      return
}

您的jsonResult 已经解包，因此无需再次解包。

谢谢

Answer 2

您不需要语句“让 jsonResponse = jsonResult”。 jsonResult 已被检查。