Thread recv = new Thread (){
        public void run(){

            byte[] message = new byte[1500];

                try {
                    s= new DatagramSocket(server_port);


                    DatagramPacket p = new DatagramPacket(message, message.length);

                                                                Log.d(TAG, "before receive" );
                    while (true){
                    s.receive(p);
                                                                Log.d(TAG, "received" );

                    final String textab = new String(message,0,p.getLength());

                                                                Log.d(TAG, "message 2 strings" );

                                     runOnUiThread(new Runnable() {


                                                                        public void run() {
                                                                       RXtexta.setText(textab);

                                                                        }
                                                                 });

                    }
                } catch (SocketException e) {
                    // TODO Auto-generated catch block
                    e.printStackTrace();
                    rstep.setText("fail socket create");
                    Log.d(TAG, "fail socket create" );
                } catch (IOException e) {
                    // TODO Auto-generated catch block
                    e.printStackTrace();
                    Log.d(TAG, "fail receive" );

                    rstep.setText("fail receive");



                }
            }


    };recv.start();