connecting to socket over wifi - android

Question

I am trying to use sockets in Android to connect over wifi to some UDP port ( some_port ) on a machine in my local network whose ip is some_ip .

When I run

socket = new Socket(some_ip, some_port);

I get no message error but the program does not seem to read this line and I can't log the error when surrounding with try/catch .

How can I debug that ?

Edit 1 : here's my try/catch

try{
    socket = new Socket(some_ip, some_port);
}
catch(ConnectException e) {
  e.printStackTrace();
}

Edit 2 : here's the entire code

private void getUDPData() throws IOException {

        class ProcessUPDTask extends AsyncTask<String, Void, Socket> {

            private Exception exception;

            private Socket socket;

            public ProcessUPDTask() throws IOException {

            }

            private void runThread(){
                new Thread() {
                    public void run() {
                        Toast.makeText(activity, "Own Message",       Toast.LENGTH_LONG).show();
                           }
                }.start();
             }


            protected Socket doInBackground(String... urls) {

                try {
                    try{
                        socket = new Socket(some_ip, some_port); 
                        socket.setSoTimeout(1500);
                    }
                    catch(IOException e) {
                       e.printStackTrace();
                    }

                    Log.d("TAG","this line is reached");
                    while(true){
                        try {
                            dataInputStream = new DataInputStream(socket.getInputStream());
                            dataOutputStream = new DataOutputStream(socket.getOutputStream());
                            System.out.println("ip: " + socket.getInetAddress());
                            System.out.println("message: " + dataInputStream.readUTF());
                            dataOutputStream.writeUTF("Hello!");
                        } catch (IOException e) {
                            // TODO Auto-generated catch block
                            e.printStackTrace();
                        }
                        finally{
                            if( socket!= null){
                                try {
                                    socket.close();
                                } catch (IOException e) {
                                    // TODO Auto-generated catch block
                                    e.printStackTrace();
                                }
                            }

                            if( dataInputStream!= null){
                                try {
                                    dataInputStream.close();
                                } catch (IOException e) {
                                    // TODO Auto-generated catch block
                                    e.printStackTrace();
                                }
                            }

                            if( dataOutputStream!= null){
                                try {
                                    dataOutputStream.close();
                                } catch (IOException e) {
                                    // TODO Auto-generated catch block
                                    e.printStackTrace();
                                }
                            }
                        }
                    }
                } catch (Exception e) {
                    this.exception = e;
                    e.printStackTrace();
                    return null;
                }
            }
            protected void onPostExecute(Socket socket) {
                // TODO: check this.exception
                // TODO: do something with the feed
            }
        }
        new ProcessUPDTask().execute();
    }

Answer 1

Try this

     try {
        Socket socket = new Socket(IP_ADDRESS, PORT);
        socket.setSoTimeout(1500);   
      } catch (IOException ex) {
         Log.e("Connection Error",String.valueOf(ex));
      }

Replace your code with this and wait some seconds(60 sec for now) you can see the error toast..

private void getUDPData() throws IOException {
        class ProcessUPDTask extends AsyncTask<String, Void, Socket> {

            private Exception exception;

            private Socket socket;

            public ProcessUPDTask() throws IOException {

            }
            protected Socket doInBackground(String... urls) {
                try {
                    try {
                        socket = new Socket("192.168.1.101", 1234);
                        socket.setSoTimeout(1500);
                    } catch (IOException e) {
                        runOnUiThread(new Runnable() {
                            @Override
                            public void run() {
                                Toast.makeText(MainActivity.this, "Error", Toast.LENGTH_LONG).show();
                            }
                        });
                    }

                    runOnUiThread(new Runnable() {
                        @Override
                        public void run() {
                            Toast.makeText(MainActivity.this, "Reached", Toast.LENGTH_LONG).show();
                        }
                    });
                    while (true) {
                        try {
                            dataInputStream = new DataInputStream(socket.getInputStream());
                            dataOutputStream = new DataOutputStream(socket.getOutputStream());
                            System.out.println("ip: " + socket.getInetAddress());
                            System.out.println("message: " + dataInputStream.readUTF());
                            dataOutputStream.writeUTF("Hello!");
                        } catch (IOException e) {
                            // TODO Auto-generated catch block
                            e.printStackTrace();
                        } finally {
                            if (socket != null) {
                                try {
                                    socket.close();
                                } catch (IOException e) {
                                    // TODO Auto-generated catch block
                                    e.printStackTrace();
                                }
                            }

                            if (dataInputStream != null) {
                                try {
                                    dataInputStream.close();
                                } catch (IOException e) {
                                    // TODO Auto-generated catch block
                                    e.printStackTrace();
                                }
                            }

                            if (dataOutputStream != null) {
                                try {
                                    dataOutputStream.close();
                                } catch (IOException e) {
                                    // TODO Auto-generated catch block
                                    e.printStackTrace();
                                }
                            }
                        }
                    }
                } catch (Exception e) {
                    this.exception = e;
                    e.printStackTrace();
                    return null;
                }
            }

            protected void onPostExecute(Socket socket) {
                // TODO: check this.exception
                // TODO: do something with the feed
            }
        }
        new ProcessUPDTask().execute();
    }

Answer 2

You can configure this and use transData() between connectivity.

private void transData(int sending_msg_int) throws IOException {

        String sending_msg = Integer.toString(sending_msg_int);
        SocketAddress socketAddress = new InetSocketAddress(ip, Data.Port);
        DatagramSocket ds = new DatagramSocket();

        byte[] buffer = sending_msg.getBytes();

        DatagramPacket dp = new DatagramPacket(buffer, buffer.length,
                socketAddress);
        ds.send(dp);
        ds.close();

    }