URLSession＆JSONSerialization斯威夫特3

Question

你读到这篇文章之前，请理解，我有点斯威夫特与一个初学者，我努力学习。我已经通过一些网站在得到答案的希望浏览，但我要么无法找到或做错误的。我一直在关注这个教程，但这是老不更新>>Tutorial I followed < <

我也试图修改一些快速3 - 虽然我可能没有这样做。

我该如何正确地做URLSession？我得到这个错误：

invalid conversion from throwing function of type'(_, _, _) throws -> Void' to non-throwing function type

下面这一行：

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

和变量 “jsonDict” - 我得到的错误，我有事先

extra arg 'error' in call.

谢谢

var urlString:String = ("http://query.yahooapis.com/v1/public/yql?q=select * from yahoo.finance.quotes where symbol IN "+stringQuotes+"&format=json&env=http://datatables.org/alltables.env").addingPercentEncoding(withAllowedCharacters: .urlHostAllowed)! 

    var url : URL = URL(string: urlString)! 
    var request: URLRequest = URLRequest(url:url) 
    let config = URLSessionConfiguration.default 
    let session = URLSession(configuration: config) 

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

     if((error) != nil) { 
      println(error.localizedDescription) 
     } 
     else { 
      var err: NSError? 

      var jsonDict = try JSONSerialization.JSONObject(with: data, options: JSONSerialization.ReadingOptions.mutableContainers, error: &err) as NSDictionary 
      if(err != nil) { 
       println("JSON Error \(err!.localizedDescription)") 
      } 
      else { 
       var quotes:NSArray = ((jsonDict.objectForKey("query") as NSDictionary).objectForKey("results") as NSDictionary).objectForKey("quote") as NSArray 
       DispatchQueue.main.async(execute: { 
        .default.post(name: Notification.Name(rawValue: kNotificationStocksUpdated), object: nil, userInfo: [kNotificationStocksUpdated:quotes]) 
       }) 
      } 
     } 
    }) 
    task.resume() 
} 

Answer 1

请找到更新的代码为雨燕3.0

var urlString:String = ("http://query.yahooapis.com/v1/public/yql?q=select * from yahoo.finance.quotes where symbol IN "+stringQuotes+"&format=json&env=http://datatables.org/alltables.env").addingPercentEncoding(withAllowedCharacters: .urlFragmentAllowed)! 

     let url : URL = URL(string: urlString)! 
     let request: URLRequest = URLRequest(url:url) 
     let config = URLSessionConfiguration.default 
     let session = URLSession(configuration: config) 

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

      if(error != nil){ 
       print(error?.localizedDescription ?? "") 
      } 
      else{ 
       do{ 
        let jsonDict:NSDictionary = try JSONSerialization.jsonObject(with: data!, options: .mutableContainers) as! NSDictionary 
        let quotes:NSArray = ((jsonDict.object(forKey: "query") as! NSDictionary).object(forKey: "results") as! NSDictionary).object(forKey: "quote") as! NSArray 
        print(quotes) 

       } 
       catch{ 
        print(error.localizedDescription) 
       } 
      } 
     }; 
     task.resume() 

注：我没有测试的代码。因为你没有指定URL参数

Answer 2

你的问题是不是在URLSessionDataTask但在您的completionHandler。更具体地说在var jsonDict = try JSONSerialization...位。 try表示您的代码可能会抛出异常，但您不处理它（catch）。这就是为什么编译器决定你的完成处理程序类型为(_, _, _) throws -> Void，而dataTask方法需要(_, _, _) -> Void。

Here你可以找到信息如何使用try/catch。