chatmain.java

benhui网的蓝牙例子

package btchat;

import javax.microedition.midlet.*;
import javax.microedition.lcdui.*;
import java.io.*;

/**
 * BlueChat example application.
 * Originally published in Java Developer's Journal (volume 9 issue 2).
 * Updated by Ben Hui on www.benhui.net.
 * Copyright: (c) 2003-2004
 * Author: Ben Hui
 *
 * YOU ARE ALLOWED TO USE THIS CODE FOR EDUCATIONAL, PERSONAL TRAINNING,
 * REFERENCE PURPOSE. YOU MAY DISTRIBUTE THIS CODE AS-IS OR MODIFIED FORM.
 * HOWEVER, YOU CANNOT USE THIS CODE FOR COMMERCIAL PURPOSE. THIS INCLUDE,
 * BUT NOT LIMITED TO, PRODUCING COMMERCIAL SOFTWARE, CONSULTANT SERVICE,
 * PROFESSIONAL TRAINNING MATERIAL.
 *
 * Main MIDlet class that execute BlueChat application.
 * <p>Description: </p>
 * <p>Copyright: Copyright (c) 2003</p>
 * @author Ben Hui
 * @version 1.0
 */
public class ChatMain extends MIDlet implements BTListener, CommandListener
{
  // shared static variables
  public static ChatMain instance;
  public static Display display;

  // debug flag
  public static boolean isDebug = false;

  // Chat app GUI components
  public InputUI inputui;
  public MessageUI messageui;
  public NameUI nameui;


  // Bluetooth network layer for BlueChat app
  public NetLayer btnet;

  /** Constructor */
  public ChatMain()
  {
    instance = this;
  }

  /** Handle starting the MIDlet */
  public void startApp() {
    log( "invoke startApp()");

    // obtain reference to Display singleton
    display = Display.getDisplay(this );

    // initialize the GUI component, and prompt for name input
    inputui = new InputUI();
    messageui = new MessageUI();
    nameui = new NameUI();
    display.setCurrent( nameui );

  }

  /** Handle pausing the MIDlet */
  public void pauseApp() {
    log( "invoke pauseApp()");
  }

  /** Handle destroying the MIDlet */
  public void destroyApp(boolean unconditional) {
    log( "invoke destroyApp()");
  }

  /** Quit the MIDlet */
  public static void quitApp() {
    instance.destroyApp(true);
    instance.notifyDestroyed();
    instance = null;
    display = null;
  }

  /**
   * Handle event/activity from Bluetooth Network layer.
   * This class is an implementation of BTListener; therefore, it handles
   * all the bluetooth network event that received by NetLayer.
   * The list of possible event are defined in BTListener.EVENT_XXX.
   * @param action event type. see NetLayer constants
   * @param param1 parameter 1 is usually the remote EndPoint that trigger the action
   * @param param2 parameter 2 is usually the argument of the action
   */
  public void handleAction( String event, Object param1, Object param2 )
  {
    log("invoke handleAction. action="+event);

    if ( event.equals( BTListener.EVENT_JOIN ) )
    {
      // a new user has join the chat room
      EndPoint endpt = (EndPoint) param1;
      String msg = endpt.remoteName + " joins the chat room";
      ChatPacket packet = new ChatPacket(NetLayer.SIGNAL_HANDSHAKE, endpt.remoteName, msg  );

      // display the join message on screen
      messageui.msgs.addElement( packet );
      messageui.repaint();

    } else if ( event.equals( BTListener.EVENT_SENT ) )
    {
      // nothing to do
    } else if ( event.equals( BTListener.EVENT_RECEIVED ) )
    {
      // a new message has received from a remote user
      EndPoint endpt = (EndPoint) param1;
      ChatPacket msg = (ChatPacket) param2;
      // render this message on screen
      messageui.msgs.addElement( msg );
      messageui.repaint();

    } else if ( event.equals( BTListener.EVENT_LEAVE ) )
    {
      // a user has leave the chat room
      EndPoint endpt = (EndPoint) param1;
      String msg = endpt.remoteName + " leaves the chat room";
      ChatPacket packet = new ChatPacket(NetLayer.SIGNAL_TERMINATE, endpt.remoteName, msg  );
      // display the leave message on screen
      messageui.msgs.addElement( packet );
      messageui.repaint();


    }

  }

  /**
   * Handle user action from BlueChat application.
   * @param c GUI command
   * @param d GUI display object
   */
  public void commandAction(Command c, Displayable d)
  {
    log( "invoke commandAction. command="+c.getLabel());
    if ( d == inputui && c.getLabel().equals("Send") )
    {
      String msg = inputui.getString();
      // send the message to all connected BlueChat remote EndPoints
      btnet.sendString( msg );

      // update the message screen to reflect the entered message.
      // create a dummy packet object to hold the entered message.
      ChatPacket packet = new ChatPacket( NetLayer.SIGNAL_MESSAGE, btnet.localName,  msg );
      messageui.msgs.addElement( packet );
      display.setCurrent( messageui );
      messageui.repaint();

    } else if ( d == nameui && ( c.getLabel().equals("Chat") || c.getLabel().equals("Chat (Debug)") ) )
    {
      // turn on debug logging on screen
      // see log() method (there are several)
      if ( c.getLabel().equals("Chat (Debug)") )
        ChatMain.isDebug = true;

      // user enters virtual chat room.
      // create and initialize Bluetooth network layer
      btnet = new NetLayer();
      String localName = nameui.text.getString();
      log("set local nick name to "+localName);

      // initialize the network layer. This will start the local BlueChat server
      btnet.init( localName, this );

      // search for existing BlueChat nodes
      btnet.query();

      // switch screen to message screen
      display.setCurrent( messageui );

    } else if ( d == inputui && c.getLabel().equals("Back") )
    {
      // just does nothing and return to message screen
      display.setCurrent( messageui );

    } else if ( d == messageui && c.getLabel().equals("Write") )
    {
      // enter input screen
      display.setCurrent( inputui );
      inputui.showUI(); // clear the input text field

    } else if ( d == messageui && c.getLabel().equals("Clear") )
    {
      // clear the history of message and refresh the message screen
      messageui.msgs.removeAllElements();
      messageui.repaint();

    } else if ( d == messageui && c.getLabel().equals("Exit") )
    {
      // disconnect from the virtual chat room.
      // this will send out TERMINATE signal to all connected
      // remote EndPoints, wait for the TERMINATE_ACK signal, and
      // disconnect all connections.
      btnet.disconnect();
      quitApp();

    } else if ( d == messageui && c.getLabel().equals("About BlueChat") )
    {
      Alert alert = new Alert( "About", "BlueChat 1.0. By Ben Hui (c) 2004. Visit www.benhui.net for more mobile dev resources.", null, AlertType.INFO );
      alert.setTimeout( Alert.FOREVER );
      display.setCurrent( alert, messageui );

    }

  }

  private static void log( String s)
  {
    System.out.println("ChatMain: "+s);

    // "M" means Main class
    if ( ChatMain.isDebug )
      ChatMain.instance.gui_log( "M", s );
  }

  public static void gui_log(String source, String s)
  {
    ChatPacket packet = new ChatPacket(NetLayer.SIGNAL_MESSAGE, source,  s );
    instance.messageui.msgs.addElement(packet);
    instance.messageui.repaint();
  }
}