MainActivity.java

package com.example.tyler.myapplication;

import android.net.wifi.WifiManager;
import android.os.Handler;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.text.format.Formatter;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;

import java.io.DataInputStream;
import java.io.DataOutputStream;
import java.io.IOException;
import java.net.ServerSocket;
import java.net.Socket;

public class MainActivity extends AppCompatActivity {

    Button button_sent;
    EditText smessage;
    TextView chat, display_status,disp,dis;
    String str, msg = "";
    int serverport = 10000;
    ServerSocket serverSocket;
    Socket client;
    Handler handler = new Handler();
    WifiManager wmanager;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        wmanager = (WifiManager) getApplicationContext().getSystemService(WIFI_SERVICE);
        String ip =
                Formatter.formatIpAddress(wmanager.getConnectionInfo().getIpAddress());
        smessage = (EditText) findViewById(R.id.smessage);
        chat = (TextView) findViewById(R.id.chat);
        disp=(TextView) findViewById(R.id.disp);
        dis=(TextView) findViewById(R.id.dis);
        display_status = (TextView)
                findViewById(R.id.display_status);
        display_status.setText("Server hosted on " + ip );
        Thread serverThread = new Thread(new serverThread());
        serverThread.start();
        button_sent = (Button) findViewById(R.id.button_sent);
        button_sent.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                Thread sentThread = new Thread(new sentMessage());
                sentThread.start();
            }
        });
    }

    class sentMessage implements Runnable {
        @Override
        public void run() {
            try {
                Socket client = serverSocket.accept();
                DataOutputStream os = new
                        DataOutputStream(client.getOutputStream());
                str = smessage.getText().toString();
                msg = msg + "\n Server : " + str;
                handler.post(new Runnable() {
                    @Override
                    public void run() {
                        chat.setText(msg);
                    }
                });
                os.writeBytes(str);
                os.flush();
                os.close();
                client.close();
            } catch (IOException e) {
            }
        }
    }

    public class serverThread implements Runnable {

        @Override
        public void run() {
            try {
                while (true) {
                    serverSocket = new ServerSocket(serverport);
                    if(serverSocket.getLocalPort()!=-1)
                    dis.setText(serverSocket.toString());
                        disp.setText("YELLO");
                        //dis.setText("ok");



                    Socket client = serverSocket.accept();
                    handler.post(new Runnable() {
                        @Override
                        public void run() {
                            display_status.setText("Connected");
                        }
                    });
                    /*******************************************
                     setup i/p streams
                     ******************************************/
                    DataInputStream in = new
                            DataInputStream(client.getInputStream());
                    String line = null;
                    while ((line = in.readLine()) != null) {
                        msg = msg + "\n Client : " + line;
                        handler.post(new Runnable() {
                            @Override
                            public void run() {
                                chat.setText(msg);
                            }
                        });
                    }
                    in.close();
                    client.close();
                    Thread.sleep(100);
                }
            } catch (Exception e) {

            }

        }


    }
}