Setcontentview() isn't running

Question

Hello, i am learning from a tutorial in witch i can send messages by UDP protocol, the sample is working and i can send and receive messages. Now i want to make a listener for port 12345 to listen the messages received, maybe its not the best way but i do this with a handler...

LinearLayout main = new LinearLayout(IpClient.this);
    main.setLayoutParams(new  LayoutParams(LayoutParams.FILL_PARENT, LayoutParams.FILL_PARENT));

    text = new TextView(IpClient.this);
    text.setLayoutParams(new LayoutParams(LayoutParams.FILL_PARENT, LayoutParams.WRAP_CONTENT));
    text.setBackgroundResource(R.drawable.edit);
    text.setText("INCOMING MESSAGES: \n ");
    text.setTextColor(Color.BLACK);

    Button b = new Button(IpClient.this);
    b.setLayoutParams(new LayoutParams(LayoutParams.WRAP_CONTENT,
            LayoutParams.WRAP_CONTENT));
    b.setText("receive");

    main.addView(text);
    main.addView(b);

    setContentView(main);

    final int server_port = 12345;

    message = new byte[1500];

    h = new Handler();

    listen = new Runnable() {

        @Override
        public void run() {
            // TODO Auto-generated method stub

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

            try {

                s = new DatagramSocket(server_port);

            } catch (SocketException e1) {
            }

            try {
                s.receive(p);
            } catch (IOException e) {

            }

            String textIn = new String(message, 0, p.getLength());
            //Toast.makeText(IpClient.this, "mesaj:" + textIn, Toast.LENGTH_SHORT)
                //    .show();

            text.setText(text.getText() + "Received - " + textIn + "\n");

            h.postDelayed(listen, 10);

        }
    };

    h.postDelayed(listen, 100);

}

The problem is that when i run the app i need to receive a message to see the content view of the app -> the textView and the button. What is wrong and how can i fix this?

Thank you very much for the help!