Java Sockets - transmission in real time

Question

i got this code form Android-er blogspot, big thanks for him to make me almost understand basic socket connections in java. So i got this client app on my android device, and computer with server running, but how could i make a loop in a client code, to make it send data from EditText in real time? (whenever it changes) Please if someone could clear it out for a complete newbie?

-----This is client code (Android-er Copyrights):

package com.exercise.AndroidClient;

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

import android.app.Activity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;

public class AndroidClient extends Activity {

EditText textOut;
TextView textIn;

 /** Called when the activity is first created. */
 @Override
 public void onCreate(Bundle savedInstanceState) { 
 super.onCreate(savedInstanceState);
 setContentView(R.layout.main);

 textOut = (EditText)findViewById(R.id.textout);
 Button buttonSend = (Button)findViewById(R.id.send);
 textIn = (TextView)findViewById(R.id.textin);
 buttonSend.setOnClickListener(buttonSendOnClickListener);
 }

 Button.OnClickListener buttonSendOnClickListener
 = new Button.OnClickListener(){

@Override
public void onClick(View arg0) {
 // TODO Auto-generated method stub
 Socket socket = null;
 DataOutputStream dataOutputStream = null;
 DataInputStream dataInputStream = null;

 try {
  socket = new Socket("192.168.1.101", 8888);
  dataOutputStream = new DataOutputStream(socket.getOutputStream());
  dataInputStream = new DataInputStream(socket.getInputStream());
  dataOutputStream.writeUTF(textOut.getText().toString());
  textIn.setText(dataInputStream.readUTF());
 } catch (UnknownHostException e) {
  // TODO Auto-generated catch block
  e.printStackTrace();
 } catch (IOException e) {
  // TODO Auto-generated catch block
  e.printStackTrace();
 }
 finally{
  if (socket != null){
   try {
    socket.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();
   }
  }

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

-----This is server code (Android-er Copyrights):

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


public class MyServer {

 public static void main(String[] args){
  ServerSocket serverSocket = null;
  Socket socket = null;
  DataInputStream dataInputStream = null;
  DataOutputStream dataOutputStream = null;

  try {
   serverSocket = new ServerSocket(8888);
   System.out.println("Listening :8888");
  } catch (IOException e) {
   // TODO Auto-generated catch block
   e.printStackTrace();
  }

  while(true){
   try {
    socket = serverSocket.accept();
    dataInputStream = new DataInputStream(socket.getInputStream());
    dataOutputStream = new DataOutputStream(socket.getOutputStream());
    System.out.println("ip: " + socket.getInetAddress());
    System.out.println("message: " + dataInputStream.readUTF());
    dataOutputStream.writeUTF("Hello!");
   } catch (IOException e) {
    // TODO Auto-generated catch block
    e.printStackTrace();
   }
   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();
     }
    }
   }
  }
 }
}

Answer 1

There are a few things you will need to change.

First of all, if you want the data to be sent in real time, you will need to change from using a Button OnClickListener to using a TextWatcher (see addTextChangedListener in TextView )

As this event will be fired every time the text changes, you will need to open your socket outside of the event (you don't want a new socket each time some text is typed), and then in your listener, you just want to send the new data down the socket.

Answer 2

You can set a text changed listener on your EditText and do the sending from there.

edittext.addTextChangedListener(new TextWatcher() {
    public void onTextChanged(CharSequence charSequence, int start, int before, int count) {
 // ... do your sending here
}

But beware that if that sending is not asynchronous, it may block text entry for the user. Network latency can be relatively high on GSM networks, so the user may be irritated, when his freshly typed characters will not immediately appear on screen.