通話中出現額外的參數“錯誤”-無法構建我的Xcode項目

Question

import Foundation

class NetworkOperation {

    lazy var config: NSURLSessionConfiguration =     NSURLSessionConfiguration.defaultSessionConfiguration()
    lazy var session: NSURLSession = NSURLSession(configuration: self.config)
    let queryURL: NSURL

    typealias JSONDictionaryCompletion = ([String: AnyObject]? -> Void)

    init(url: NSURL) {
        self.queryURL = url
    }

    func downloadJSONFromURL(completion: JSONDictionaryCompletion) {

        let request = NSURLRequest(URL: queryURL)
        let dataTask = session.dataTaskWithRequest(request) {
            (let data, let response, let error) in

// 1.檢查HTTP響應以獲取成功的GET請求

            if let httpResponse = response as? NSHTTPURLResponse {
                switch httpResponse.statusCode {
                case 200:

// 2.使用數據創建JSON對象

                    let jsonDictionary = NSJSONSerialization.JSONObjectWithData(data, options: nil, error: nil)
                    completion(jsonDictionary)
                default:
                    print("GET request not successful. HTTP status code: \(httpResponse.statusCode)")
                }
            } else {
                print("Error: Not a valid HTTP response")
            }
        }

        dataTask.resume()
    }
}

在“使用數據創建JSON對象”步驟中，我不斷收到“調用中的額外參數'error'”。 怎么了？ 我找不到文檔來進一步幫助我。

Answer 1

您可以通過這種方式做到這一點。

do{
        var jsonDictionary  = try NSJSONSerialization.JSONObjectWithData(data, options:NSJSONReadingOptions.MutableContainers)
        //completion(jsonDictionary)
    }catch{
       // report error
    }

Answer 2

在步驟2的頂部：創建json ....

添加此行：

var err: NSError?

Answer 3

// 1.檢查HTTP響應以獲取成功的GET請求

            if let httpResponse = response as? NSHTTPURLResponse {
                switch httpResponse.statusCode {
                case 200:

// 2.使用數據創建JSON對象

                    let jsonDictionary = NSJSONSerialization.JSONObjectWithData(data, options: nil, error: nil) as? [String: AnyObject]
                    completion(jsonDictionary)
                default:
                    println("GET request not successful. HTTP status code: \(httpResponse.statusCode)")
                }
            } else {
                println("Error: Not a valid HTTP response")
            }
        }

        dataTask.resume()
    }
}

終於想通了！ 謝謝大家的投入！