Swift 3 URLSession.shared() Ambiguous reference to

问题:

Hello I have working json parsing code for swift2.2 but when i use it for Swift 3.0 gives me that error

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

My codes here

   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()

Thanks for ideas.

回答1:

The compiler is confused by the function signature. You can fix it like this:

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

But, note that we don\'t have to cast \"request\" as URLRequest in this signature if it was declared earlier as URLRequest instead of NSMutableURLRequest:

var request = URLRequest(url:myUrl!)

This is the automatic casting between NSMutableURLRequest and the new URLRequest that is failing and which forced us to do this casting here.

回答2:

You have init\'d myRequest as NSMutableURLRequest, you need this:

var URLRequest

Swift is ditching both the NSMutable... thing. Just use var for the new classes.

回答3:

Xcode 8 and Swift 3.0

Using 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 Delegate call:

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){

}

Using Block 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()

Working fine for me.. try it 100% result guarantee

回答4:

This problem is caused by URLSession has two dataTask methods

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

The first one has URLRequest as parameter, and the second one has URL as parameter, so we need to specify which type to call, for example, I want to call the second method

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

回答5:

In my case error was in NSURL

let url = NSURL(string: urlString)

In Swift 3 you must write just URL:

let url = URL(string: urlString)

回答6:

Tested xcode 8 stable version ; Need to use var request variable with URLRequest() With thats you can easily fix that (bug)

var request = URLRequest(url:myUrl!) And

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

Worked fine ! Thank you guys, i think help many people. !

回答7:

In swift 3 the compiler is confused by the function signature. Specifying it will clear the error. Also convert the url string to type URL. The following code worked for me.

   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

回答8:

Short and concise answer for Swift 3:

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

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

}.resume()

回答9:

 // 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()

回答10:

To load data via a GET request you don\'t need any URLRequest (and no semicolons)

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

回答11:

For Swift 3 and 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?)
                }
            })
        }
     }

//Note: You can always use debugger to check error

回答12:

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()

回答13:

For me I do this to find,

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

Can\'t use

\"let url = NSURL(string: urlString)