Non blocking socket channel

TCPClientNIO.java

import android.content.Context;
import android.util.Log;
import android.widget.Toast;

import java.io.IOException;
import java.net.InetSocketAddress;
import java.net.UnknownHostException;
import java.nio.ByteBuffer;
import java.nio.CharBuffer;
import java.nio.channels.SocketChannel;
import java.nio.charset.Charset;
import java.nio.charset.CharsetDecoder;

/**
 * Created by kheldiente on 11/18/16.
 */
public class TCPClientNIO {

    private static final String TAG = TCPClientNIO.class.getSimpleName();

    public SocketChannel socketChannel = null;
    public InetSocketAddress isa = null;
    public RecvThread rt = null;

    Context ctx;

    boolean connected = false;
    boolean connectionRefused = false;
    boolean connectionTimeout = false;

    String SERVER_IP = "";
    String SERVER_PORT = "";

    String mThreadName = "";

    public TCPClientNIO(Context context, String ip, String port, String threadName) {
        ctx = context;
        SERVER_IP = ip;
        SERVER_PORT = port;
        mThreadName = threadName;

        socketChannel = null;
        isa = null;
        rt = null;

        connected = false;
        connectionTimeout = false;
        connectionRefused = false;

    }


    public boolean isConnected() {
        return connected;
    }

    public boolean isConnectionTimedOut()
    {
        return connectionTimeout;
    }

    public boolean isConnectionRefused() {
        return connectionRefused;
    }

    public void run() {
        int result = 0;


        connected = false;
        connectionRefused = false;
        connectionTimeout = false;

        try {
            socketChannel = SocketChannel.open();
            isa = new InetSocketAddress(SERVER_IP, Integer.parseInt(SERVER_PORT));
            socketChannel.connect(isa);
            socketChannel.configureBlocking(false);
            receiveMessage();
            Log.d(TAG, "connected");
            connected = true;
        } catch (UnknownHostException e) {
            e.printStackTrace();
            Log.d(TAG, "connection refused");
            connectionRefused = true;
        } catch (IOException e) {
            e.printStackTrace();
            Log.d(TAG, "connection refused");
            connectionRefused = true;
        }
    }

    public String getMessageFromServer() {
        return messageFromServer;
    }

    public void setMessageFromServer(String msg) {
        messageFromServer = msg;
    }

    public void stop() {

        if(connected) {
            Log.d(TAG, "init to connection closing");
            try {
                messageFromServer = null;
                interruptThread();
                socketChannel.close();
                connected = false;
                connectionRefused = false;
                connectionTimeout = false;
                Log.d(TAG, "connection closed");
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
    }

    public boolean sendMessage(String msg) {
        int nBytes = 0;

        boolean sent = false;

        if (msg == null) {
            Toast.makeText(ctx, "Msg is null", Toast.LENGTH_SHORT).show();
            return sent;
        }

        if(connected) {
            Log.d(TAG, "sending message:  " + msg);
            ByteBuffer bytebuf = ByteBuffer.allocate(1024);
            try {
                bytebuf = ByteBuffer.wrap(msg.getBytes());
                nBytes = socketChannel.write(bytebuf);
                sent = true;
                Log.d(TAG, "sent message");
            } catch (IOException e) {
                e.printStackTrace();
                Log.d(TAG, "connection timeout when sending");
                connectionTimeout = true;
            }
        }
        return sent;
    }

    public void receiveMessage() {
        rt = new RecvThread(mThreadName, socketChannel); // Receive Thread is an alias for thread!!
        rt.start();
    }

    public void interruptThread() {
        rt.val = false;
    }

    String messageFromServer = null;

    public class RecvThread extends Thread {

        public SocketChannel sc = null;
        public boolean val = true;

        public RecvThread(String str, SocketChannel client) {
            super(str);
            sc = client;
        }

        public void run() {
            int nBytes = 0;
            ByteBuffer buf = ByteBuffer.allocate(2048);
            try {
                while (val) {
                    while ((nBytes = nBytes = socketChannel.read(buf)) > 0) {
                        buf.flip();
                        Charset charset = Charset.forName("us-ascii");
                        CharsetDecoder decoder = charset.newDecoder();
                        CharBuffer charBuffer = decoder.decode(buf);
                        String result = charBuffer.toString();
                        messageFromServer = result;
                        Log.d(TAG, "message: " + result);
                        buf.flip();
                    }
                }
                Log.d(TAG, "listener while loop has stopped");

            } catch (IOException e) {
                e.printStackTrace();
                Log.d(TAG, "connection timeout");
                connectionTimeout = true;
            }


        }
    }
}