Client/Server example: editable message sent from server

In previouse example of "Bi-directional communication between Client and Server, using ServerSocket, Socket, DataInputStream and DataOutputStream" and "Prevent program blocked by DataInputStream.readUTF()", the server always send a fixed welcome message to client. It's modified to add a EditText for user to enter title to be sent.


Server side code:

package com.example.androidserversocket;

import java.io.DataInputStream;
import java.io.DataOutputStream;
import java.io.IOException;
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.os.Bundle;
import android.app.Activity;
import android.widget.CheckBox;
import android.widget.EditText;
import android.widget.TextView;

public class MainActivity extends Activity {
 
 EditText textTitle;

 TextView info, infoip, msg;
 String message = "";
 ServerSocket serverSocket;
 
 CheckBox optWelcome;

 @Override
 protected void onCreate(Bundle savedInstanceState) {
  super.onCreate(savedInstanceState);
  setContentView(R.layout.activity_main);
  info = (TextView) findViewById(R.id.info);
  infoip = (TextView) findViewById(R.id.infoip);
  msg = (TextView) findViewById(R.id.msg);
  
  optWelcome = (CheckBox)findViewById(R.id.optwelcome);

  infoip.setText(getIpAddress());

  Thread socketServerThread = new Thread(new SocketServerThread());
  socketServerThread.start();
  
  textTitle = (EditText)findViewById(R.id.title);
 }

 @Override
 protected void onDestroy() {
  super.onDestroy();

  if (serverSocket != null) {
   try {
    serverSocket.close();
   } catch (IOException e) {
    // TODO Auto-generated catch block
    e.printStackTrace();
   }
  }
 }

 private class SocketServerThread extends Thread {

  static final int SocketServerPORT = 8080;
  int count = 0;

  @Override
  public void run() {
   Socket socket = null;
   DataInputStream dataInputStream = null;
   DataOutputStream dataOutputStream = null;

   try {
    serverSocket = new ServerSocket(SocketServerPORT);
    MainActivity.this.runOnUiThread(new Runnable() {

     @Override
     public void run() {
      info.setText("I'm waiting here: "
        + serverSocket.getLocalPort());
     }
    });

    while (true) {
     socket = serverSocket.accept();
     dataInputStream = new DataInputStream(
       socket.getInputStream());
     dataOutputStream = new DataOutputStream(
       socket.getOutputStream());

     String messageFromClient = "";
     
     //Check available() before readUTF(),
     //to prevent program blocked if dataInputStream is empty
     if(dataInputStream.available()>0){
      messageFromClient = dataInputStream.readUTF();
     }
     
     count++;
     message += "#" + count + " from " + socket.getInetAddress()
       + ":" + socket.getPort() + "\n"
       + "Msg from client: " + messageFromClient + "\n";

     MainActivity.this.runOnUiThread(new Runnable() {

      @Override
      public void run() {
       msg.setText(message);
      }
     });
     
     if(optWelcome.isChecked()){

      String msgReply = count + ": " + textTitle.getText().toString();
      dataOutputStream.writeUTF(msgReply);
     }

    }
   } catch (IOException e) {
    // TODO Auto-generated catch block
    e.printStackTrace();
    final String errMsg = e.toString();
    MainActivity.this.runOnUiThread(new Runnable() {

     @Override
     public void run() {
      msg.setText(errMsg);
     }
    });
    
   } finally {
    if (socket != null) {
     try {
      socket.close();
     } catch (IOException e) {
      // TODO Auto-generated catch block
      e.printStackTrace();
     }
    }

    if (dataInputStream != null) {
     try {
      dataInputStream.close();
     } catch (IOException e) {
      // TODO Auto-generated catch block
      e.printStackTrace();
     }
    }

    if (dataOutputStream != null) {
     try {
      dataOutputStream.close();
     } catch (IOException e) {
      // TODO Auto-generated catch block
      e.printStackTrace();
     }
    }
   }
  }

 }

 private String getIpAddress() {
  String ip = "";
  try {
   Enumeration<NetworkInterface> enumNetworkInterfaces = NetworkInterface
     .getNetworkInterfaces();
   while (enumNetworkInterfaces.hasMoreElements()) {
    NetworkInterface networkInterface = enumNetworkInterfaces
      .nextElement();
    Enumeration<InetAddress> enumInetAddress = networkInterface
      .getInetAddresses();
    while (enumInetAddress.hasMoreElements()) {
     InetAddress inetAddress = enumInetAddress.nextElement();

     if (inetAddress.isSiteLocalAddress()) {
      ip += "SiteLocalAddress: "
        + inetAddress.getHostAddress() + "\n";
     }

    }

   }

  } catch (SocketException e) {
   // TODO Auto-generated catch block
   e.printStackTrace();
   ip += "Something Wrong! " + e.toString() + "\n";
  }

  return ip;
 }
}

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    tools:context=".MainActivity" >

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_gravity="center_horizontal"
        android:autoLink="web"
        android:text="http://android-er.blogspot.com/"
        android:textStyle="bold" />
    
    <EditText
        android:id="@+id/title"
        android:layout_width="match_parent"
        android:layout_height="wrap_content" />

    <TextView
        android:id="@+id/info"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content" />
    <TextView
        android:id="@+id/infoip"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content" />
    
    <CheckBox
        android:id="@+id/optwelcome"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:checked="true"
        android:text="Send Welcome when connect" />

    <ScrollView
        android:layout_width="match_parent"
        android:layout_height="match_parent" >

        <TextView
            android:id="@+id/msg"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content" />
    </ScrollView>

</LinearLayout>

Client side, refer to previous example "Prevent program blocked by DataInputStream.readUTF()".

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