jump.java

JAVASCRIPT的界面说明JAVASCRIPT的界面说明JAVASCRIPT的界面说明JAVASCRIPT的界面说明

package net.frog_parrot.jump;

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

/**
 * This is the main class of the tumbleweed game.
 *
 * @author Carol Hamer
 */
public class Jump extends MIDlet implements CommandListener {

  //---------------------------------------------------------
  //   game object fields

  /**
   * the command to end the game.
   */
  private Command myExitCommand = new Command("Exit", Command.EXIT, 99);

  /**
   * the command to start moving when the game is paused.
   */
  private Command myGoCommand = new Command("Go", Command.SCREEN, 1);

  /**
   * the command to pause the game.
   */
  private Command myPauseCommand = new Command("Pause", Command.SCREEN, 1);

  /**
   * the command to start a new game.
   */
  private Command myNewCommand = new Command("Play Again", Command.SCREEN, 1);

  /**
   * the the canvas that all of the game will be drawn on.
   */
  JumpCanvas myCanvas;

  /**
   * the thread that advances the cowboy.
   */
  GameThread myGameThread;

  //-----------------------------------------------------
  //    initialization and game state changes

  /**
   * Initialize the canvas and the commands.
   */
  public Jump() {
    myCanvas = new JumpCanvas(this);
    myCanvas.addCommand(myExitCommand);
    myCanvas.addCommand(myGoCommand);
    myCanvas.setCommandListener(this);
  }

  /**
   * Switch the command to the play again command.
   */
  void setNewCommand() {
    myCanvas.removeCommand(myPauseCommand);
    myCanvas.removeCommand(myGoCommand);
    myCanvas.addCommand(myNewCommand);
  }

  /**
   * Switch the command to the go command.
   */
  void setGoCommand() {
    myCanvas.removeCommand(myPauseCommand);
    myCanvas.removeCommand(myNewCommand);
    myCanvas.addCommand(myGoCommand);
  }

  /**
   * Switch the command to the pause command.
   */
  void setPauseCommand() {
    myCanvas.removeCommand(myNewCommand);
    myCanvas.removeCommand(myGoCommand);
    myCanvas.addCommand(myPauseCommand);
  }

  //----------------------------------------------------------------
  //  implementation of MIDlet

  /**
   * Start the application.
   */
  public void startApp() throws MIDletStateChangeException {
    myGameThread = new GameThread(myCanvas);
    myCanvas.start();
  }
  
  /**
   * stop and throw out the garbage.
   */
  public void destroyApp(boolean unconditional) 
      throws MIDletStateChangeException {
    myGameThread.requestStop();
    myGameThread = null;
    myCanvas = null;
    System.gc();
  }

  /**
   * request the thread to pause.
   */
  public void pauseApp() {
    setGoCommand();
    myGameThread.pause();
  }

  //----------------------------------------------------------------
  //  implementation of CommandListener

  /*
   * Respond to a command issued on the Canvas.
   * (either reset or exit).
   */
  public void commandAction(Command c, Displayable s) {
    if(c == myGoCommand) {
      myCanvas.removeCommand(myGoCommand);
      myCanvas.addCommand(myPauseCommand);
      myGameThread.go();
    } else if(c == myPauseCommand) {
      myCanvas.removeCommand(myPauseCommand);
      myCanvas.addCommand(myGoCommand);
      myGameThread.go();
    } else if(c == myNewCommand) {
      myCanvas.removeCommand(myNewCommand);
      myCanvas.addCommand(myGoCommand);
      myGameThread.requestStop();
      myGameThread = new GameThread(myCanvas);
      System.gc();
      myCanvas.reset();
    } else if(c == myExitCommand) {
      try {
	destroyApp(false);
	notifyDestroyed();
      } catch (MIDletStateChangeException ex) {
      }
    }
  }
  
}