Chat app using socket connection

Hi,
Here is the sample code for chatting two devices. It only required internet connection.


/*
 ServerActivity for getting ip-address of your device.
*/

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.net.InetAddress;
import java.net.NetworkInterface;
import java.net.ServerSocket;
import java.net.Socket;
import java.net.SocketException;
import java.util.Enumeration;

import android.app.Activity;
import android.os.Bundle;
import android.os.Handler;
import android.util.Log;
import android.widget.TextView;

public class ServerActivity extends Activity {

    private TextView serverStatus;

    // default ip
    public static String SERVERIP = "192.68.100.104";//10.10.10.201

    // designate a port
    public static final int SERVERPORT = 8080;

    private final Handler handler = new Handler();

    private ServerSocket serverSocket;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.server);
        serverStatus = (TextView) findViewById(R.id.server_status);

        SERVERIP = getLocalIpAddress();

        Thread fst = new Thread(new ServerThread());
        fst.start();
    }

    public class ServerThread implements Runnable {

        public void run() {
            try {
                if (SERVERIP != null) {
                    handler.post(new Runnable() {
                        @Override
                        public void run() {
                            serverStatus.setText("Listening on IP: " + SERVERIP);
                        }
                    });
                    serverSocket = new ServerSocket(SERVERPORT);
                    while (true) {
                        // listen for incoming clients
                        Socket client = serverSocket.accept();
                        handler.post(new Runnable() {
                            @Override
                            public void run() {
                                serverStatus.setText("Connected.");
                            }
                        });

                        try {
                            BufferedReader in = new BufferedReader(new InputStreamReader(client.getInputStream()));
                            String line = null;
                            while ((line = in.readLine()) != null) {
                                Log.d("ServerActivity", line);
                                handler.post(new Runnable() {
                                    @Override
                                    public void run() {
                                        // do whatever you want to the front end
                                        // this is where you can be creative
                                    }
                                });
                            }
                            break;
                        } catch (Exception e) {
                            handler.post(new Runnable() {
                                @Override
                                public void run() {
                                    serverStatus.setText("Oops. Connection interrupted. Please reconnect your phones.");
                                }
                            });
                            e.printStackTrace();
                        }
                    }
                } else {
                    handler.post(new Runnable() {
                        @Override
                        public void run() {
                            serverStatus.setText("Couldn't detect internet connection.");
                        }
                    });
                }
            } catch (Exception e) {
                handler.post(new Runnable() {
                    @Override
                    public void run() {
                        serverStatus.setText("Error");
                    }
                });
                e.printStackTrace();
            }
        }
    }

    // gets the ip address of your phone's network
    private String getLocalIpAddress() {
        try {
            for (Enumeration<NetworkInterface> en = NetworkInterface.getNetworkInterfaces(); en.hasMoreElements();) {
                NetworkInterface intf = en.nextElement();
                for (Enumeration<InetAddress> enumIpAddr = intf.getInetAddresses(); enumIpAddr.hasMoreElements();) {
                    InetAddress inetAddress = enumIpAddr.nextElement();
                    if (!inetAddress.isLoopbackAddress()) { return inetAddress.getHostAddress().toString(); }
                }
            }
        } catch (SocketException ex) {
            Log.e("ServerActivity", ex.toString());
        }
        return null;
    }

    @Override
    protected void onStop() {
        super.onStop();
        try {
             // make sure you close the socket upon exiting
             serverSocket.close();
         } catch (IOException e) {
             e.printStackTrace();
         }
    }

}


/*
 Running on client device. just pass the ip-address that you getting from ServerActivity class.
*/
import java.io.BufferedWriter;
import java.io.OutputStreamWriter;
import java.io.PrintWriter;
import java.net.InetAddress;
import java.net.Socket;

import android.app.Activity;
import android.os.Bundle;
import android.os.Handler;
import android.util.Log;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.EditText;

public class ClientActivity extends Activity {

    private EditText serverIp;

    private Button connectPhones;

    private String serverIpAddress = "192.68.100.104";

    private boolean connected = false;

    private final Handler handler = new Handler();

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

        serverIp = (EditText) findViewById(R.id.server_ip);
        connectPhones = (Button) findViewById(R.id.connect_phones);
        connectPhones.setOnClickListener(connectListener);
    }

    private final OnClickListener connectListener = new OnClickListener() {

        @Override
        public void onClick(View v) {
            if (!connected) {
                serverIpAddress = serverIp.getText().toString();
                if (!serverIpAddress.equals("")) {
                    Thread cThread = new Thread(new ClientThread());
                    cThread.start();
                }
            }
        }
    };

    public class ClientThread implements Runnable {

        public void run() {
            try {
                InetAddress serverAddr = InetAddress.getByName(serverIpAddress);
                Log.d("ClientActivity", "C: Connecting...");
                Socket socket = new Socket(serverAddr, ServerActivity.SERVERPORT);
                connected = true;
                while (connected) {
                    try {
                        Log.d("ClientActivity", "C: Sending command.");
                        PrintWriter out = new PrintWriter(new BufferedWriter(new OutputStreamWriter(socket
                                    .getOutputStream())), true);
                            // where you issue the commands
                            out.println("Hey Server!");
                            Log.d("ClientActivity", "C: Sent.");
                    } catch (Exception e) {
                        Log.e("ClientActivity", "S: Error", e);
                    }
                }
                socket.close();
                Log.d("ClientActivity", "C: Closed.");
            } catch (Exception e) {
                Log.e("ClientActivity", "C: Error", e);
                connected = false;
            }
        }
    }
}


/*
client.xml
*/

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical" android:layout_width="fill_parent"
    android:layout_height="fill_parent">
    <TextView android:layout_width="fill_parent"
        android:layout_height="wrap_content" android:text="@string/hello" />
    <EditText android:layout_height="wrap_content"
        android:layout_width="match_parent" android:text="192.68.100.104"
        android:id="@+id/server_ip"></EditText>
    <Button android:text="Button" android:id="@+id/connect_phones"
        android:layout_width="wrap_content" android:layout_height="wrap_content"></Button>
</LinearLayout>

/*
server.xml
*/

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    >
<TextView 
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"
    android:id="@+id/server_status"
    />
</LinearLayout>

Note: don't forgot to add internet permission in manifest file.
<uses-permission android:name="android.permission.INTERNET"/>