Android Open Source - async-socket-android Async Connection

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License

The source code is released under:

This is free and unencumbered software released into the public domain. Anyone is free to copy, modify, publish, use, compile, sell, or distribute this software, either in source code form or as a co...

Java Source Code

package net.omplanet.network.asyncsocket;
/*ww  w . j  av  a2  s. c  om*/
import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.OutputStreamWriter;
import java.net.InetSocketAddress;
import java.net.Socket;
import java.net.UnknownHostException;

import android.util.Log;

/**
 * The AsyncConnection class is an AsyncTask that can be used to open a socket connection with a server and to write/read data asynchronously.
 *
 * The socket connection is initiated in the background thread of the AsyncTask which will stay alive reading data in a while loop
 * until disconnect() method is called from outside or the connection has been lost.
 *
 * When the socket reads data it sends it to the ConnectionHandler via didReceiveData() method in the same thread of AsyncTask.
 * To write data to the server call write() method from outside thread. As the input and output streams are separate there will be no problem with synchronisation.
 *
 * A useful tip: if you wish to avoid connection timeout to happen while the application is inactive try to write some meaningless data periodically as a heartbeat.  
 * A useful tip: if you wish to keep the connection alive for longer that the activity  life cycle than consider using services.
 * 
 * Created by StarWheel on 10/08/13.
 * 
 */
public class AsyncConnection extends android.os.AsyncTask<Void, String, Exception> {
    private String url;
    private int port;
    private int timeout;
    private ConnectionHandler connectionHandler;

    private BufferedReader in;
    private BufferedWriter out;
  private Socket socket;
    private boolean interrupted = false;

  private String TAG = getClass().getName();

  public AsyncConnection(String url, int port, int timeout, ConnectionHandler connectionHandler) {
        this.url = url;
        this.port = port;
        this.timeout = timeout;
    this.connectionHandler = connectionHandler;
  }

  @Override
  protected void onProgressUpdate(String... values) {
    super.onProgressUpdate(values);
  }

  @Override
  protected void onPostExecute(Exception result) {
    super.onPostExecute(result);
    Log.d(TAG, "Finished communication with the socket. Result = " + result);
        //TODO If needed move the didDisconnect(error); method call here to implement it on UI thread.
  }

  @Override
  protected Exception doInBackground(Void... params) {
    Exception error = null;

    try {
      Log.d(TAG, "Opening socket connection.");
      socket = new Socket();
      socket.connect(new InetSocketAddress(url, port), timeout);
      
      in = new BufferedReader(new InputStreamReader(socket.getInputStream()));
      out = new BufferedWriter(new OutputStreamWriter(socket.getOutputStream()));

            connectionHandler.didConnect();

            while(!interrupted) {
                String line = in.readLine();
                //Log.d(TAG, "Received:" + line);
                connectionHandler.didReceiveData(line);
            }
    } catch (UnknownHostException ex) {
      Log.e(TAG, "doInBackground(): " + ex.toString());
      error = interrupted ? null : ex;
    } catch (IOException ex) {
      Log.d(TAG, "doInBackground(): " + ex.toString());
      error = interrupted ? null : ex;
    } catch (Exception ex) {
            Log.e(TAG, "doInBackground(): " + ex.toString());
            error = interrupted ? null : ex;
        } finally {
          try {
                 socket.close();
                 out.close();
          in.close();
            } catch (Exception ex) {}
        }

        connectionHandler.didDisconnect(error);
    return error;
  }

  public void write(final String data) {
    try {
      Log.d(TAG, "writ(): data = " + data);
      out.write(data + "\n");
      out.flush();
    } catch (IOException ex) {
      Log.e(TAG, "write(): " + ex.toString());
    } catch (NullPointerException ex) {
      Log.e(TAG, "write(): " + ex.toString());
    }
  }

  public void disconnect() {
        try {
          Log.d(TAG, "Closing the socket connection.");

            interrupted = true;
            if(socket != null) {
              socket.close();
            }
            if(out != null & in != null) {
              out.close();
        in.close();
            }
        } catch (IOException ex) {
      Log.e(TAG, "disconnect(): " + ex.toString());
        }
  }
}

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