源码

发送广播UDP但不在其他Android设备上接收


我正在尝试开发一个发送一些广播消息的应用程序,并从其他Android设备接收一些答案.我在从其他设备接收UDP消息时遇到一些麻烦.我应该提一下,这段代码适用于Gingerbread,但是在JellyBean上它不再起作用了,我不知道可能是什么问题.

这是我发送广播消息的地方(我知道其他设备在端口5000上侦听):

 private void sendUDPMessage(String msg) {

    try {
        DatagramSocket clientSocket = new DatagramSocket();

        clientSocket.setBroadcast(true);
        InetAddress address = InetAddress.getByName(Utils.getBroadcastAddress());

        byte[] sendData;

        sendData = msg.getBytes();
        DatagramPacket sendPacket = new DatagramPacket(sendData,
                sendData.length, address, 5000);
        clientSocket.send(sendPacket);

        clientSocket.close();
    } catch (Exception e) {
        e.printStackTrace();
    }

}

这是我收到它的地方:

private void start_UDP()
{
    try {
            serverSocketUDP = new DatagramSocket(5000);
        }
    catch (Exception e) {

        Log.i(LOGTAG, "Exception opening DatagramSocket UDP");
    }

    final byte[] receiveData = new byte[1024];


    while(runningUDP) {
        Log.d(LOGTAG, "Waiting for Broadcast request in ServerUDP.");

        final DatagramPacket receivePacket = new DatagramPacket(receiveData, receiveData.length);

        serverSocketUDP.receive(receivePacket);


                byte[] sendData = new byte[1024];
                InetAddress address = receivePacket.getAddress();
                int port = receivePacket.getPort();
                if(!receivePacket.getAddress().getHostAddress().equals(Utils.getLocalIpAddress()))
                {
                    String req = new String(receivePacket.getData(), 0, receivePacket.getLength());


                    Log.d(LOGTAG, "Received UDP message : "+req+" from: "+receivePacket.getAddress().getHostAddress());
                }
                      }// while ends
       }//method ends

我应该提到这两个函数在2个不同的线程中是分开的,所以我可以同时发送和接收.

我还获得了以下锁:

    powerManager =(PowerManager)context.getSystemService(Context.POWER_SERVICE);
    wakeLock = powerManager.newWakeLock(PowerManager.PARTIAL_WAKE_LOCK ,LOGTAG); // PARTIAL_WAKE_LOCK Only keeps CPU on
    wifiManager = (WifiManager)context.getSystemService(Context.WIFI_SERVICE);
    wifiLock = wifiManager.createWifiLock(3, LOGTAG);
    multicastLock = wifiManager.createMulticastLock(LOGTAG);

    wakeLock.acquire();
    multicastLock.acquire();
    wifiLock.acquire();

以及Manifest文件的权限:








我已经测试过是否使用wireshark和tcpdump发送消息并发送它们.而且,更奇怪的是,我接收到我发送的广播消息(但我丢弃它们因为我不需要处理自己发送的消息)但是我没有收到从其他设备发送的广播消息(应该有相同的格式,只有源地址不同并且包含的??消息,无论哪种方式都不应影响广播消息).

如果您有任何想法,请告诉我,因为我真的用完了我可以尝试的任何其他东西.任何帮助,将不胜感激.谢谢!

编辑:
我已经做了一些测试,即使我在每个手机上运行ifconfig wlan0并且它表示类似的东西

  ifconfig wlan0
  wlan0: ip 169.254.17.28 mask 255.255.0.0 flags [up broadcast multicast]

这意味着接口处于活动状态且IP已设置,并且可以接收广播消息和组播消息,但在我使用时

                 InetAddress in=InetAddress.getByName("169.254.17.28");
            if (in.isReachable(1000))
                Log.i(LOGTAG, "host is reachable");
            else
                Log.i(LOGTAG, "host is not reachable");

它显示在日志中主机无法访问.

这是我打开Wi-Fi的地方

    private void startWifiAdhoc() {

    WifiManager wifiManager =     (WifiManager)SharingFileService.context.getSystemService(Context.WIFI_SERVICE);
    String command="";
    if (condWifiAdhoc == false) {

        condWifiAdhoc=true;
        wifiInterface = Utils.getWifiInterface();


        wifiManager.setWifiEnabled(true);
        localIP = Utils.getLinkLocalAddress();
    }
    else
    {
        wifiManager.setWifiEnabled(true);
        localIP = Utils.getLinkLocalAddress();
    }
        // Set wifi ad-hoc
        command = context.getFilesDir().getPath()
                + "/iwconfig " + wifiInterface + " mode ad-hoc essid "
                + "mcp" + " channel " + "1" + " commit/n";

        Log.i(LOGTAG, command);
        Utils.rootExec(command);


        Log.i(LOGTAG, "Ip address used :" + localIP);
        command = context.getFilesDir().getPath()
                + "/ifconfig " + wifiInterface + " " + localIP
                + " netmask 255.255.0.0 up/n";



        Log.i(LOGTAG, command);
        Utils.rootExec(command);

}
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