Android UDP不接收数据

Question

我在 android 中有一个 DatagramSocket 的实现，它试图从设置为服务器的 STA 设备接收数据。我有两个端口，一个是命令端口，第二个是数据流。命令端口在 TCP 协议上运行并且工作正常，而 UDP 端口由于某种原因没有接收到数据。我可以向 TCP 端口发送开始传输命令，并且 UDP 端口开始输出数据，从运行模拟器的计算机上观察到，但数据报套接字没有接收到数据。我已经在物理设备上尝试过，但仍然没有运气。我也知道这是可行的，因为我有一个 UDP 的 python 实现，运行在同一台设备上运行良好。

我的实现概览：

• TCP 和 UDP 在不同的不同线程上运行（使用协程）。

• 我使用的权限包括：

  uses-permission android:name = "android.permission.INTERNET"
  uses-permission android:name = "android.permission.ACCESS_NETWORK_STATE"
  

• 最大 UDP 数据包大小 200 字节

• Android 代码片段（不工作）

  private val hostIP: String = "10.0.0.1"
  private val commandPort: Int = 6660
  private val streamPort: Int = 6670
  
  
  private fun sendTcpCommand(command: Int = 2) {
  
    GlobalScope.launch {
        try {
            val socketCommand = Socket(inetAddress, commandPort)
  
            if (socketCommand.isConnected) {
                val clientCommandOutput = DataOutputStream(socketCommand.getOutputStream())
  
                val oByteArray = byteArrayOf(command.toByte())
  
                clientCommandOutput.write(oByteArray)
  
            } else {
                Log.d(
                    TAG,
                    "createIOConnections: socket is not connect?: ${socketCommand.isClosed}"
                )
            }
            val inputStream = DataInputStream(socketCommand.getInputStream())
            val response = inputStream.readBytes()
            val responseMap = responseInterpreter(response, command)
            socketCommand.close()
  
        } catch (e: Exception) {
            e.printStackTrace()
        }
    }
  
    private fun openUdpPort() {
        GlobalScope.launch {
            try {
                val datagramSocketStream: DatagramSocket? = DatagramSocket(null)
                datagramSocketStream?.reuseAddress = true
                datagramSocketStream?.broadcast = true
                datagramSocketStream?.bind(InetSocketAddress(streamPort))
  
                val bufferLen = 200
                val bufferByteArray = ByteArray(bufferLen)
                val datagramPacket = DatagramPacket(bufferByteArray, bufferByteArray.size)
  
                datagramSocketStream?.receive(datagramPacket)
  
                val noBytesRead = datagramPacket.length
                interpretUdpData(datagramPacket.data)
  
            } catch (e: Exception) {
                e.printStackTrace()
            }
        }
    }
  }
  

• Python 代码片段（在计算机上运行）

  CONTROL_SERVER_IP = "10.0.0.1"
  STREAM_SERVER_IP = "10.0.0.100"
  
  if self.socket == self.CONTROL_SOCK:
        try:
            self.sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
        except socket.error as e:
            print("Failed to create socket.")
            print(f'Error: {e}')
            sys.exit()
        print("Socket Created.")
  
  
  
        # Connect the socket to the port where the server is listening
        server_address = (self.server_ip, self.socket)
        print(sys.stderr, 'connecting to %s port %s' % server_address)
        self.sock.settimeout(5)
        try:
            self.sock.connect(server_address)
            print("Port is open")
        except socket.timeout as e:
            print(
                "Server connection failed. Please check that the server is on and that the server and client are connected.")
            print(f'Error: {e}')
            sys.exit()
    else:
        try:
            self.sock = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
        except socket.error as e:
            print("Failed to create socket.")
            print(f'Error: {e}')
            sys.exit()
        print("Socket Created.")
  
  
  
        # Connect the socket to the port where the server is listening
        server_address = (self.server_ip, self.socket)
        print(sys.stderr, 'connecting to %s port %s' % server_address)
        self.sock.settimeout(5)
        try:
            self.sock.bind(server_address)
            print("Port is open")
        except socket.timeout as e:
            print(
                "Server connection failed. Please check that the server is on and that the server and client are connected.")
            print(f'Error: {e}')
            sys.exit()
    return self.sock
  
  
        print("Reading Meaurements.")
        self.thread_running = True
        measurements = Measurements()
        full_chunk = b''
        new_packet = True
        pointer = 0
        while self.thread_running:
            try:
                msg, address = sock.recvfrom(200)
                # msg = sock.recv(16)  # 16 byte buffer
            except socket.error as e:
                print(f'Error: {e}')
                break
                self.disconnect()
                self.terminate_thread()
                sys.exit()
  

• 在 android UDP 套接字上尝试使用地址 0.0.0.0 和 10.0.0.100。

任何关于为什么这不适用于 Android 的指针都会很棒！

Answer 1

您没有在设备上设置接收端口

val datagramSocketStream: DatagramSocket? = DatagramSocket(PORT)

这本身不是问题，但这意味着您依赖于接收广播消息。你可能有两个问题让你绊倒。模拟器可能正在更改您的预期 IP，或者您的手机可能不接受广播消息。 见此链接：Datagram (UDP) receiver not working - not receiving broadcast packets