json - 对成员 'dataTask(with:completionHandler:)' 错误的引用不明确

Question

这个问题已经有答案了:

Swift 3 URLSession.shared() Ambiguous reference to member 'dataTask(with:completionHandler:) error (bug) (14 个回答)

已关闭 5 年前。

我收到此错误:

Ambiguous reference to member 'dataTask(with:completionHandler:)'

查看代码发生的位置(添加错误行下方的注释)

{
    for metadata in metadataObjects{
        let decodedData:AVMetadataMachineReadableCodeObject = metadata as! AVMetadataMachineReadableCodeObject

        if currentISBN == decodedData.stringValue { continue; }

        currentISBN = decodedData.stringValue

        //self.lblDataInfo.text = decodedData.stringValue
        //self.lblDataType.text = decodedData.type

        let url = URL(string: "https://www.googleapis.com/books/v1/volumes?q=isbn:"+decodedData.stringValue+"&key=AIzaSyAf9fhYZLHjjqfWiTXZeSikNTZOt5yNwoU")
        let session = URLSession.shared
        let request = NSMutableURLRequest(url: url!)
        request.httpMethod = "GET"
        request.addValue(Bundle.main.bundleIdentifier ?? "", forHTTPHeaderField: "X-Ios-Bundle-Identifier")

        //HERE I GET THE ERROR ON THIS LINE:
        **let task = session.dataTask(with: request, completionHandler: { (data, response, error) -> Void in**

            if error != nil {
                print(error)
                return
            }

            do {
                //let jsonResult = NSJSONSerialization.JSONObjectWithData(data, options: NSJSONReadingOptions.MutableContainers, error: nil) as! NSDictionary

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

                if json is [String: AnyObject] {
                    print(json)
                    if let error = json["error"] as? String {
                        print(error);
                    } else if let items = json["items"] as? [[String: AnyObject]] {

                        for item in items {
                            print(item)

                            let book_id = item["id"] as? String

                            if let volumeInfo = item["volumeInfo"] as? [String: AnyObject] {
                                let book_title = volumeInfo["title"] as? String
                                DispatchQueue.main.async(execute: { () -> Void in
                                    self.lblDataInfo.text = "ISBN: "+self.currentISBN!+"  ID:"+book_id!
                                    self.lblDataType.text = book_title
                                })
                            }

                            break // for now, only show first
                        }

                    } else {
                        DispatchQueue.main.async(execute: { () -> Void in
                            self.lblDataInfo.text = "ISBN: "+self.currentISBN!+"  Not identified"
                            self.lblDataType.text = ""
                        })
                    }
                }

            } catch let jsonError {
                print(jsonError)
            }

        })
        task.resume()

    }
}

Answer 1

该方法需要 native URLRequest，而不是 NSMutableURLRequest。

var request = URLRequest(url: url!)

Swift 3+ 中的 JSON 字典是 [String:Any] 而不是 [String:AnyObject]