Swift 中的 JSON 错误

Question

我是 Swift 和 API 编程新手，遇到以下错误:

uncaught exception 'NSInvalidArgumentException', reason: '-[__NSCFNumber length]

这是导致此错误的行:

print(json[“totalPostsByUser”])

有关更多上下文，这是更完整的代码示例:

let jsonStr = NSString(data: request.HTTPBody!, encoding: NSUTF8StringEncoding)
let task = session.dataTaskWithRequest(request, completionHandler: { (data, response, error) -> Void in
   let httpResponse = response as? NSHTTPURLResponse
   var err: NSError?

   if httpResponse!.statusCode == 201 {
      if error == nil {
         let jsonStr = NSString(data: data!, encoding: NSUTF8StringEncoding)
         let jsonData: NSData = jsonStr!.dataUsingEncoding(NSUTF8StringEncoding)!
         do {
            if let json: AnyObject = try NSJSONSerialization.JSONObjectWithData(jsonData, options: NSJSONReadingOptions.AllowFragments) {
               let responseString = NSString(data: data!, encoding:  NSUTF8StringEncoding)
               print(responseString)
               print(json["totalPostsByUser"])
               totalPostsByUser = (json["totalPostsByUser"] as? Int)!
            }
         } catch let parseError {
         }
      }
   }
}

Answer 1

我认为你需要用下面的代码替换一些代码，

if let json: NSMutableDictionary = try NSJSONSerialization.JSONObjectWithData(jsonData, options: NSJSONReadingOptions.AllowFragments) as? NSMutableDictionary
    {
               let responseString = NSString(data: data!, encoding:  NSUTF8StringEncoding)
               print(responseString)
               //print(json["totalPostsByUser"])
               print(json.valueForKey("totalPostsByUser"))
               //totalPostsByUser = (json["totalPostsByUser"] as? Int)!
    }

将任何对象转换为 MutableDictionary，这样可以很容易地从键中提取值。

希望这对您有帮助。