Swift 3 URLSession.shared() 对成员 'dataTask(with:completionHandler:) 错误的引用不明确（bug）

Question

您好，我正在 json 解析 swift2.2 的代码，但是当我将它用于 Swift 3.0 时，出现了错误

ViewController.swift:132:31: Ambiguous reference to member 'dataTask(with:completionHandler:)'

我的代码在这里

   let listUrlString =  "http://bla.com?batchSize=" + String(batchSize) + "&fromIndex=" + String(fromIndex)
    let myUrl = URL(string: listUrlString);
    let request = NSMutableURLRequest(url:myUrl!);
    request.httpMethod = "GET";

    let task = URLSession.shared().dataTask(with: request) {
        data, response, error in

        if error != nil {
            print(error!.localizedDescription)
            DispatchQueue.main.sync(execute: {
                AWLoader.hide()
            })

            return
        }

        do {

            let json = try JSONSerialization.jsonObject(with: data!, options: .mutableContainers) as? NSArray

            if let parseJSON = json {

                var items = self.categoryList

                items.append(contentsOf: parseJSON as! [String])

                if self.fromIndex < items.count {

                    self.categoryList = items
                    self.fromIndex = items.count

                    DispatchQueue.main.async(execute: {

                        self.categoriesTableView.reloadData()

                        AWLoader.hide()

                    })
                }else if( self.fromIndex == items.count){


                    DispatchQueue.main.async(execute: {

                        AWLoader.hide()

                    })

                }



            }

        } catch {
            AWLoader.hide()
            print(error)

        }
    }

    task.resume()

谢谢你的想法。

Answer 1

编译器被函数签名弄糊涂了。您可以这样修复它：

let task = URLSession.shared.dataTask(with: request as URLRequest) {

但是，请注意，我们不必在此签名中将 "request" 强制转换为 URLRequest 如果它之前已声明为 URLRequest 而不是 NSMutableURLRequest:

var request = URLRequest(url:myUrl!)

这是 NSMutableURLRequest 和新的 URLRequest 之间的自动转换失败，迫使我们在这里进行转换。

Answer 2

您已将 myRequest 初始化为 NSMutableURLRequest，您需要：

var URLRequest

Swift 正在放弃 NSMutable... 这两个东西。只需将 var 用于新的类.

Answer 3

已测试 xcode 8 稳定版； 需要将 var request 变量与 URLRequest() 一起使用，这样你就可以轻松修复（错误)

var request = URLRequest(url:myUrl!) 和

let task = URLSession.shared().dataTask(with: request as URLRequest) { }

工作得很好！谢谢你们，我认为可以帮助很多人。 !

Answer 4

这个问题是因为 URLSession 有两个 dataTask 方法

open func dataTask(with request: URLRequest, completionHandler: @escaping (Data?, URLResponse?, Error?) -> Swift.Void) -> URLSessionDataTask
open func dataTask(with url: URL, completionHandler: @escaping (Data?, URLResponse?, Error?) -> Swift.Void) -> URLSessionDataTask

第一个有URLRequest参数，第二个有URL参数，所以我们需要指定调用哪种类型，比如我要调用第二个方法

let task = URLSession.shared.dataTask(with: url! as URL) {
    data, response, error in
    // Handler
}

Answer 5

Xcode 8 和 Swift 3.0

使用 URLSession:

 let url = URL(string:"Download URL")!
 let req = NSMutableURLRequest(url:url)
 let config = URLSessionConfiguration.default
 let session = URLSession(configuration: config, delegate: self, delegateQueue: OperationQueue.main)

 let task : URLSessionDownloadTask = session.downloadTask(with: req as URLRequest)
task.resume()

URLSession 委托调用：

func urlSession(_ session: URLSession, task: URLSessionTask, didCompleteWithError error: Error?) {

}


func urlSession(_ session: URLSession, downloadTask: URLSessionDownloadTask, 
didWriteData bytesWritten: Int64, totalBytesWritten writ: Int64, totalBytesExpectedToWrite exp: Int64) {
                   print("downloaded \(100*writ/exp)" as AnyObject)

}

func urlSession(_ session: URLSession, downloadTask: URLSessionDownloadTask, didFinishDownloadingTo location: URL){

}

使用块 GET/POST/PUT/DELETE:

 let request = NSMutableURLRequest(url: URL(string: "Your API URL here" ,param: param))!,
        cachePolicy: .useProtocolCachePolicy,
        timeoutInterval:"Your request timeout time in Seconds")
    request.httpMethod = "GET"
    request.allHTTPHeaderFields = headers as? [String : String] 

    let session = URLSession.shared

    let dataTask = session.dataTask(with: request as URLRequest) {data,response,error in
        let httpResponse = response as? HTTPURLResponse

        if (error != nil) {
         print(error)
         } else {
         print(httpResponse)
         }

        DispatchQueue.main.async {
           //Update your UI here
        }

    }
    dataTask.resume()

对我来说效果很好..尝试一下 100% 结果保证

Answer 6

 // prepare json data
        let mapDict = [ "1":"First", "2":"Second"]

        let json = [ "title":"ABC" , "dict": mapDict ] as [String : Any]
        let jsonData : NSData = NSKeyedArchiver.archivedData(withRootObject: json) as NSData

        // create post request
        let url = NSURL(string: "http://httpbin.org/post")!
        let request = NSMutableURLRequest(url: url as URL)
        request.httpMethod = "POST"

        // insert json data to the request
        request.httpBody = jsonData as Data


        let task = URLSession.shared.dataTask(with: request as URLRequest){ data,response,error in
            if error != nil{
                return
            }
            do {
                let result = try JSONSerialization.jsonObject(with: data!, options: []) as? [String:AnyObject]

                print("Result",result!)

            } catch {
                print("Error -> \(error)")
            }
        }

        task.resume()

Answer 7

要通过 GET 请求加载数据，您不需要任何 URLRequest（也不需要分号）

let listUrlString =  "http://bla.com?batchSize=" + String(batchSize) + "&fromIndex=" + String(fromIndex)
let myUrl = URL(string: listUrlString)!
let task = URLSession.shared.dataTask(with: myUrl) { ...

Answer 8

对我来说，我这样做是为了找到，

let url = URL(string: urlString)
URLSession.shared.dataTask(with: url!) { (data, response, error) in ...}

无法使用

"let url = NSURL(string: urlString)

Answer 9

对于 Swift 3 和 Xcode 8:

      var dataTask: URLSessionDataTask?

      if  let url = URL(string: urlString) {
            self.dataTask = URLSession.shared.dataTask(with: url, completionHandler: { (data, response, error) in

                if let error = error {
                    print(error.localizedDescription)
                } else if let httpResponse = response as? HTTPURLResponse, httpResponse.statusCode == 200 {
                     // You can use data received.
                    self.process(data: data as Data?)
                }
            })
        }
     }

//注意：您可以随时使用调试器检查错误

Answer 10

在swift 3 中，编译器被函数签名弄糊涂了。指定它将清除错误。同时将 url 字符串转换为类型 URL。以下代码对我有用。

   let urlString = "http://bla.com?batchSize="
   let pathURL = URL(string: urlString)!
   var urlRequest = URLRequest(url:pathURL)

    let session = URLSession.shared
    let dataTask = session.dataTask(with: urlRequest as URLRequest) { (data,response,error) in

Answer 11

let task = URLSession.shared.dataTask(with: request as URLRequest, completionHandler: { data,response,error in
        if error != nil{
            print(error!.localizedDescription)
            return
        }
        if let responseJSON = (try? JSONSerialization.jsonObject(with: data!, options: [])) as? [String:AnyObject]{
            if let response_token:String = responseJSON["token"] as? String {
                print("Singleton Firebase Token : \(response_token)")
                completion(response_token)
            }
        }
    })
    task.resume()

Answer 12

Swift 3 的简短回答：

guard let requestUrl = URL(string: yourURL) else { return }

let request = URLRequest(url:requestUrl)
URLSession.shared.dataTask(with: request) {
    (data, response, error) in
    ...

}.resume()

Answer 13

在我的案例中，错误出现在 NSURL

let url = NSURL(string: urlString)

在 Swift 3 中你必须只写 URL:

let url = URL(string: urlString)

Answer 14

Xcode10.1Swift4

这对我有用：

let task: URLSessionDataTask = session.dataTask(with: request as URLRequest) { (data, response, error) -> Void in
...

关键是在 URLSessionDataTask 类型声明中添加。

Swift 3 URLSession.shared() 对成员 'dataTask(with:completionHandler:) 错误的引用不明确（bug）

Swift 3 URLSession.shared() Ambiguous reference to member 'dataTask(with:completionHandler:) error (bug)

json

ios

swift3

Xcode10.1Swift4