Android UDP 未接收数据

问题描述

我在 android 中有一个 DatagramSocket 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，第二个是传输数据。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数据。从运行模拟器的计算机上观察，我可以向 TCP 端口发送开始传输命令，UDP 端口开始输出数据，但是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这个，但仍然没有运气。我也知道这是有效的，因为我有一个使用相同设备运行的 UDP 的 python 实现，运行正常。

我的实现概述：

TCP 和 UDP 运行在不同的线程上（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（从计算机运行）

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,'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()

尝试在 android UDP 套接字上使用地址'0.0.0.0 和 10.0.0.100。

关于为什么这不能在 Android 上运行的任何指示都会很棒！

解决方法

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失望。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。请参阅此链接：Datagram (UDP) receiver not working - not receiving broadcast packets

android android android-wifi datagram udp udp