在android上无法接收UDP数据包?

时间:2011-03-18 18:51:58

标签: java android sockets udp broadcastreceiver

我尝试在Android上实现UDP服务器,我可以将数据包发送到服务器,但无法接收它。此外,我尝试运行接收器没有Android,它的工作原理。问题在哪里?

测试的本地发件人:

int send_packet(uint8_t* data) {
    int retcode;
    int socket_out;
    int broadcast = 1;
    struct sockaddr_in addr;

    socket_out = socket(AF_INET, SOCK_DGRAM, 0);
    if ( socket_out < 0 )
        return -1;

    setsockopt(socket_out, SOL_SOCKET, SO_BROADCAST, &broadcast, sizeof broadcast);

    memset(&addr, 0, sizeof(addr));
    addr.sin_family = AF_INET;
    addr.sin_addr.s_addr = htonl(INADDR_BROADCAST);
    addr.sin_port=htons(PORT_NUMBER);

    retcode = sendto(socket_out, data, sizeof(packet_data_t), 0,
        (struct sockaddr *) &addr, sizeof(addr));
    perror("sendto");

    close(socket_out);

    return 0;
}

Android接收器:

public void run(){
   try {
       byte[] buffer = new byte[BUFFER_SIZE];
       DatagramSocket socket = new DatagramSocket(getPort());
       //socket.setBroadcast(true);
       while(true){
           DatagramPacket packet = new DatagramPacket(buffer, buffer.length );
           socket.receive(packet);
           (new CallbackWrapper(getPacketReciever())).run();
       }
    } catch (IOException e) {
        e.printStackTrace();
    }
}

ps我在HTC Legend上运行我的应用程序,而不是在模拟器上运行

1 个答案:

答案 0 :(得分:1)

主要问题在于这一行:

DatagramSocket socket = new DatagramSocket(getPort());

您假设设备的本地主机与机器/计算机相同,但设备有自己的网卡,因此在任何网络中都有自己的IP,以及他自己的网络地址IP,这是他自己。只能通过机器的端口访问设备。