How to receive data using UDP in Android?

Question

I use the following code to receive the data from a particular port. It\'s not working in Android. But sending data to particular port is working fine.

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Answer 1

Used Port numbers

Create Datagram packet

 try {
            mDataGramSocket = new DatagramSocket(Config.PORT_NUMBER);
            mDataGramSocket.setReuseAddress(true);
            mDataGramSocket.setSoTimeout(1000);
        } catch (SocketException e) {
            e.printStackTrace();
        } 

Call below function through AsyncTask

Create Function to receive infinitely

public void receive() {


    String text;

    byte[] message = new byte[1500];
    DatagramPacket p = new DatagramPacket(message, message.length);



    try {


        while (true) {  // && counter < 100 TODO
            // send to server omitted
            try {
                mDataGramSocket.receive(p);
                text = new String(message, 0, p.getLength());
                // If you're not using an infinite loop:
                //mDataGramSocket.close();

            } catch (SocketTimeoutException | NullPointerException e) {
                // no response received after 1 second. continue sending

                e.printStackTrace();
            }
        }


    } catch (Exception e) {

        e.printStackTrace();
        // return "error:" + e.getMessage();
        mReceiveTask.publish("error:" + e.getMessage());
    }

    // return "out";


}

Answer 2

If you are using the emulator you may need setup redirects, remember the emulator is behind a virtual router.

In other words, type these commands in;

telnet localhost 5554
redir add udp:9876:9876

and try again.