Swift 到 Swift 2 [重复]

Question

我有这两个功能：

func handleReceivedDataWithNotification(notification:NSNotification){
        let userInfo = notification.userInfo! as Dictionary
        let receivedData:NSData = userInfo["data"] as! NSData

        let message = NSJSONSerialization.JSONObjectWithData(receivedData, options: NSJSONReadingOptions.AllowFragments, error: nil) as NSDictionary
        let senderPeerId:MCPeerID = userInfo["peerID"] as! MCPeerID
        let senderDisplayName = senderPeerId.displayName

        if message.objectForKey("string")?.isEqualToString("New Game") == true{
            let alert = UIAlertController(title: "TicTacToe", message: "\(senderDisplayName) has started a new Game", preferredStyle: UIAlertControllerStyle.Alert)

            alert.addAction(UIAlertAction(title: "OK", style: UIAlertActionStyle.Default, handler: nil))

            self.presentViewController(alert, animated: true, completion: nil)

            resetField()
        }else{
            var field:Int? = message.objectForKey("field")?.integerValue
            var player:String? = message.objectForKey("player") as? String

            if field != nil && player != nil{
                fields[field!].player = player
                fields[field!].setPlayer_1(player!)

                if player == "x"{
                    currentPlayer = "o"
                }else{
                    currentPlayer = "x"
                }

                checkResults()

            }

        }


    }


    func fieldTapped (recognizer:UITapGestureRecognizer){
        let tappedField  = recognizer.view as! TTTImageView
        tappedField.setPlayer_1(currentPlayer)

        let messageDict = ["field":tappedField.tag, "player":currentPlayer]

        let messageData = NSJSONSerialization.dataWithJSONObject(messageDict, options: NSJSONWritingOptions.PrettyPrinted, error: nil)

        var error:NSError?

        appDelegate.mpcHandler.session.sendData(messageData, toPeers: appDelegate.mpcHandler.session.connectedPeers, withMode: MCSessionSendDataMode.Reliable, error: &error)

        if error != nil{
            print("error: \(error?.localizedDescription)")
        }

        checkResults()


    }

如果我因为现在已经升级而尝试在 Swift 2 中运行它们，我会收到以下错误：

Extra argument 'error' in call.

我在以下几行中收到该错误：

let message = NSJSONSerialization.JSONObjectWithData(receivedData, options: NSJSONReadingOptions.AllowFragments, error: nil) as NSDictionary

let messageData = NSJSONSerialization.dataWithJSONObject(messageDict, options: NSJSONWritingOptions.PrettyPrinted, error: nil)

我需要做什么来解决这些问题？

我尝试添加一个 try 和 catch 并执行，但随后程序的其余部分因变量未初始化而中断。

感谢您提供的任何帮助。

Answer 1

只需删除末尾的error 参数，并将其替换为try/catch 块。

do
{
  moc.hasChanges
  try moc.save()
}
catch let error as NSError
{
  NSLog("Unresolved error \(error), \(error.userInfo)")
}