Android Asynctask Sending Udp Packet

I want to use asynctask to send a datagram packet, but it not work!! I have add all permission that may need! I think that the problem may be in the asynctask of socket.send(

Solution 1:

Yes, well you need to actually allocate the socket, the exception is a null pointer because you declared the socket but did not allocate it before using it. Now, this should work, but you will be constantly allocating a new socket. You should take the line: socket = new DatagramSocket() that I inserted below and put that in the onCreate most likely.

protected Boolean doInBackground(String... arg0) {
        byte [] ip_bytes = new byte[] {(byte)192,(byte)168,(byte)1,(byte)1};
        try {
            inet_addr = InetAddress.getByAddress(ip_bytes );
        } catch (UnknownHostException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
        Log.e("AT command: ","at_cmd)");    
        byte[] buffer = (at_cmd + "\r").getBytes();
            DatagramPacket packet = new DatagramPacket(buffer, buffer.length,     inet_addr, PORT);
            try {
                socket= new DatagramSocket();
                socket.send(packet);
            } catch (IOException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
        Log.e("///send at command","at command topic");
        return null;
    }