背景：

我希望能够在我的iOS应用程序和服务器之间发送和接收UDP数据包。服务器将所有传入消息回显给应用程序客户端。 服务器已测试并确认可以正常工作
。我有一个StartViewController，它启动了两个实现GCDAsyncUdpSocketDelegate的类，一个用于发送，一个用于接收。“发送套接字”正在工作，服务器接收到消息。

问题：

在发送后，该应用程序再也不会取回传入的消息。监听套接字设置有些问题，因为didReceiveData永远不会被调用。

我做错了吗？

开始：

class StartViewController: UIViewController {

   var inSocket : InSocket!
   var outSocket : OutSocket!

   override func viewDidLoad() {
       super.viewDidLoad()
       inSocket = InSocket()
       outSocket = OutSocket()
   }

   @IBAction func goButton(sender: UIButton) {
       outSocket.send("This is a message!")
   }
}

接收：

class InSocket: NSObject, GCDAsyncUdpSocketDelegate {

   let IP = "255.255.255.255"
   let PORT:UInt16 = 5556
   var socket:GCDAsyncUdpSocket!

   override init(){
       super.init()
       setupConnection()
   }

   func setupConnection(){
       var error : NSError?
       socket = GCDAsyncUdpSocket(delegate: self, delegateQueue: dispatch_get_main_queue())
       socket.bindToPort(PORT, error: &error)
       socket.enableBroadcast(true, error: &error)
       socket.joinMulticastGroup(IP, error: &error)
       socket.beginReceiving(&error)
   }

   func udpSocket(sock: GCDAsyncUdpSocket!, didReceiveData data: NSData!, fromAddress address: NSData!,      withFilterContext filterContext: AnyObject!) {
       println("incoming message: \(data)");
   }
}

发送：

class OutSocket: NSObject, GCDAsyncUdpSocketDelegate {

   let IP = "90.112.76.180"
   let PORT:UInt16 = 5556
   var socket:GCDAsyncUdpSocket!

   override init(){
       super.init()
       setupConnection()
   }

   func setupConnection(){
       var error : NSError?
       socket = GCDAsyncUdpSocket(delegate: self, delegateQueue: dispatch_get_main_queue())
       socket.connectToHost(IP, onPort: PORT, error: &error)
   }

   func send(message:String){
       let data = message.dataUsingEncoding(NSUTF8StringEncoding)
       socket.sendData(data, withTimeout: 2, tag: 0)
   }

   func udpSocket(sock: GCDAsyncUdpSocket!, didConnectToAddress address: NSData!) {
       println("didConnectToAddress");
   }

   func udpSocket(sock: GCDAsyncUdpSocket!, didNotConnect error: NSError!) {
       println("didNotConnect \(error)")
   }

   func udpSocket(sock: GCDAsyncUdpSocket!, didSendDataWithTag tag: Int) {
       println("didSendDataWithTag")
   }

   func udpSocket(sock: GCDAsyncUdpSocket!, didNotSendDataWithTag tag: Int, dueToError error: NSError!) {
        println("didNotSendDataWithTag")
   }
}

编辑： 添加了被遗忘的代码行。