public class Server  {

     public static void main(String[] args) throws Exception {

            ZMQ.Context ctx = ZMQ.context(1);

            ZMQ.Socket socket = ctx.socket(ZMQ.REP);
            socket.bind("tcp://192.168.56.1:5570");
            System.out.println("Started");

            while (!Thread.currentThread().isInterrupted()) {

                byte[] request = socket.recv(0);
                String string = new String(request);
                System.out.println("Received request: ["+string+"].");

                try {
                    Thread.sleep(100);
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }

                socket.send("We got message".getBytes(), 0);
            }

            System.out.println("finished");
            socket.close();
            ctx.term();
     }
}

public interface ConnectionReadyListnener {

        void onServerConnectionEstablished();

}

public class Connection extends AsyncTask<Void, Void, Void> {

    public ConnectionReadyListnener listener=null;
    public static ZMQ.Context context;
    public static ZMQ.Socket socket;


    @Override
    protected Void doInBackground(Void... params) {

        context = ZMQ.context(1);
        socket = context.socket(ZMQ.DEALER);
        socket.setIdentity("12345".getBytes(ZMQ.CHARSET));
        socket.connect("tcp://192.168.56.1:5570");

        return null;
    }

    @Override
    protected void onPostExecute(Void result) {
        super.onPostExecute(result);
        listener.onServerConnectionEstablished();
    }

}

public class MainActivity extends Activity implements ConnectionReadyListnener{
    Connection connection;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        connection = new Connection();
        connection.listener=this;
        connection.execute();
    }

    @Override
    public void onServerConnectionEstablished() {
        Toast.makeText(getApplicationContext(), "connected", Toast.LENGTH_SHORT).show();
        new TestAsynk().execute();

    }


}

public class TestAsynk extends AsyncTask<Void, Void, Void>{

    @Override
    protected Void doInBackground(Void... params) {
        Connection.socket.send("Test".getBytes(), 0);
        return null;
    }

}