Android Socket Client

Hi,

I'm doing a desktop server application in java with android clients. I'm using sockets to provide the communication.

I have create an instance of tcpClient on MainActivity and I would like to know how could I call the method 'sendMessage' on other activities.

Should I create an instance of tcpClient on all activities?

Thanks

Server class

import java.net.*;
import java.io.*;

public class Server {

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

        boolean listening = true;

        try (ServerSocket serverSocket = new ServerSocket(4444)){

            while(listening){
                new ServerThread(serverSocket.accept()).start();
            }
        } catch (IOException e) {
            System.out.println("Could not listen on port: 4444");
            System.exit(-1);
        }

    }
}

ServerThread

import java.net.*;
import java.io.*;

public class ServerThread extends Thread {

    private Socket socket = null;

    public ServerThread(Socket socket) {
        super("ServerThread");
        this.socket = socket;
    }

    public void run() {

        try (
            PrintWriter out = new PrintWriter(socket.getOutputStream(), true);
            BufferedReader in = new BufferedReader(
                new InputStreamReader(
                    socket.getInputStream()));
        ) {
            String inputLine, outputLine;
            GameProtocol gp = new GameProtocol();
            outputLine = gp.processInput(null);
            //System.out.println(outputLine);
            //out.println(outputLine);

            while ((inputLine = in.readLine()) != null) {
                //System.out.println(outputLine);
                outputLine = gp.processInput(inputLine);
                System.out.println(outputLine);
                out.println(outputLine);
                if (outputLine.equals("Bye"))
                    break;
            }
            socket.close();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

TcpClient class

import android.util.Log;

import java.io.*;
import java.net.*;

/**
 * Created by andrecorreia on 03/06/16.
 */
public class TcpClient {

    public static final String SERVER_IP = "10.0.2.2"; // computer IP address
    public static final int SERVER_PORT = 4444;

    // message to send to the server
    private String mServerMessage;
    // sends message received notifications
    private OnMessageReceived mMessageListener = null;
    // while this is true, the server will continue running
    private boolean mRun = false;
    // used to send messages
    private PrintWriter mBufferOut;
    // used to read messages from the server
    private BufferedReader mBufferIn;

    /**
     * Constructor of the class. OnMessagedReceived listens for the messages received from server
     */
    public TcpClient(OnMessageReceived listener) {
        mMessageListener = listener;
    }

    /**
     * Sends the message entered by client to the server
     *
     * @param message text entered by client
     */
    public void sendMessage(String message) {
        if (mBufferOut != null && !mBufferOut.checkError()) {
            mBufferOut.println(message);
            mBufferOut.flush();
        }
    }

    /**
     * Close the connection and release the members
     */
    public void stopClient() {
        Log.i("Debug", "stopClient");

        // send mesage that we are closing the connection
        //sendMessage(Constants.CLOSED_CONNECTION + "Kazy");

        mRun = false;

        if (mBufferOut != null) {
            mBufferOut.flush();
            mBufferOut.close();
        }

        mMessageListener = null;
        mBufferIn = null;
        mBufferOut = null;
        mServerMessage = null;
    }

    public void run() {

        mRun = true;

        try {
            //here you must put your computer's IP address.
            InetAddress serverAddr = InetAddress.getByName(SERVER_IP);

            //InetAddress serverAddr = InetAddress.getLocalHost();
            Log.e("TCP Client", "C: Connecting...");

            //create a socket to make the connection with the server
            Socket socket = new Socket("192.168.1.92", SERVER_PORT);

            try {
                Log.i("Debug", "inside try catch");
                //sends the message to the server
                mBufferOut = new PrintWriter(new BufferedWriter(new OutputStreamWriter(socket.getOutputStream())), true);

                //receives the message which the server sends back
                mBufferIn = new BufferedReader(new InputStreamReader(socket.getInputStream()));
                // send login name
                //sendMessage(Constants.LOGIN_NAME + PreferencesManager.getInstance().getUserName());
                //sendMessage("Hi");
                //in this while the client listens for the messages sent by the server
                while (mRun) {
                    mServerMessage = mBufferIn.readLine();
                    if (mServerMessage != null && mMessageListener != null) {
                        //call the method messageReceived from MyActivity class
                        mMessageListener.messageReceived(mServerMessage);
                    }

                }
                Log.e("RESPONSE FROM SERVER", "S: Received Message: '" + mServerMessage + "'");

            } catch (Exception e) {

                Log.e("TCP", "S: Error", e);

            } finally {
                //the socket must be closed. It is not possible to reconnect to this socket
                // after it is closed, which means a new socket instance has to be created.
                socket.close();
            }

        } catch (Exception e) {

            Log.e("TCP", "C: Error", e);

        }

    }

    //Declare the interface. The method messageReceived(String message) will must be implemented in the MyActivity
    //class at on asynckTask doInBackground
    public interface OnMessageReceived {
        public void messageReceived(String message);
    }
}

Main Activity

import android.app.Activity;
import android.content.Intent;
import android.os.AsyncTask;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.view.View.OnClickListener;


public class MainActivity extends Activity implements OnClickListener {

    public static TcpClient tcpClient;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        new ConnectTask().execute("");

        // Set up click listeners for all the buttons
        View playNowButton = findViewById(R.id.playNow_button);
        playNowButton.setOnClickListener(this);

        View optionsButton = findViewById(R.id.options_button);
        optionsButton.setOnClickListener(this);

        View helpButton = findViewById(R.id.help_button);
        helpButton.setOnClickListener(this);

        View exitButton = findViewById(R.id.exit_button);
        exitButton.setOnClickListener(this);
        //---------------------------------------------
    }


    @Override
    public void onClick(View v) {
        Intent i;
        switch (v.getId()){
            case R.id.playNow_button:
                i = new Intent(this, PlayNowActivity.class);
                startActivity(i);
                break;
            case R.id.options_button:
                i = new Intent(this, OptionsActivity.class);
                tcpClient.sendMessage("options");
                startActivity(i);
                break;
            case R.id.help_button:
                i = new Intent(this, HelpActivity.class);
                tcpClient.sendMessage("help");
                startActivity(i);
                break;
            case R.id.exit_button:
                finish();
                break;
        }
    }

    public class ConnectTask extends AsyncTask<String,String,TcpClient> {

        @Override
        protected TcpClient doInBackground(String... message) {

            //we create a TCPClient object and
            tcpClient = new TcpClient(new TcpClient.OnMessageReceived() {
                @Override
                //here the messageReceived method is implemented
                public void messageReceived(String message) {

                    //this method calls the onProgressUpdate
                    publishProgress(message);

                }
            });
            tcpClient.run();

            return null;
        }

        @Override
        protected void onProgressUpdate(String... values) {
            super.onProgressUpdate(values);
        /*View view = adapter.getChildView(0, 0, false, null, null);
        TextView text = (TextView) view.findViewById(R.id.betChildOdd);
        child2.get(0).get(0).put("OLD", text.getText().toString());
        child2.get(0).get(0).put(CONVERTED_ODDS, values[0].toString());
        child2.get(0).get(0).put("CHANGE", "TRUE");
        adapter.notifyDataSetChanged();*/
        }
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.menu_main, menu);
        return true;
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        // Handle action bar item clicks here. The action bar will
        // automatically handle clicks on the Home/Up button, so long
        // as you specify a parent activity in AndroidManifest.xml.
        int id = item.getItemId();

        //noinspection SimplifiableIfStatement
        if (id == R.id.action_settings) {
            return true;
        }

        return super.onOptionsItemSelected(item);
    }

}

Options Activity

import android.app.Activity;
import android.content.Intent;
import android.content.SharedPreferences;
import android.os.Bundle;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;

import java.io.PrintWriter;
import java.net.Socket;

public class OptionsActivity extends Activity implements OnClickListener{

    private PrintWriter printwriter;
    private EditText textField;
    private String message;
    private String pieceSelected;

    TextView response;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_options);

        textField = (EditText) findViewById(R.id.name_editText);

        // Set up click listeners for all the buttons
        View saveButton = findViewById(R.id.saveOptions_button);
        //saveButton.setOnClickListener(this);

        View backOptionsButton = findViewById(R.id.backOptions_button);
        backOptionsButton.setOnClickListener(this);

        View choosePieceButton = findViewById(R.id.choosePiece_button);
        choosePieceButton.setOnClickListener(this);

        saveButton.setOnClickListener(new OnClickListener() {

            @Override
            public void onClick(View arg0) {
                message = textField.getText().toString(); // get the text message on the text field

                message+=";";
                message+=pieceSelected;

                MainActivity.tcpClient.sendMessage(message);
            }
        });
    }

    //@Override
    public void onClick(View v) {
        if (v.getId() == R.id.backOptions_button) {
            finish();
        } else if (v.getId() == R.id.saveOptions_button) {

        } else if (v.getId() == R.id.choosePiece_button) {
            Intent i = new Intent(this, GridViewPiecesActivity.class);
            startActivityForResult(i,1);
        }

    }

    public void onActivityResult(int requestCode, int resultCode, Intent data) {
        super.onActivityResult(requestCode, resultCode, data);
        if (requestCode == 1) {
            if(resultCode == RESULT_OK){
                pieceSelected=data.getStringExtra("edittextvalue");
            }
        }
    }

}