frametrigger.java

一个基于J2ME的pacman游戏

/**
 * PacMan for J2ME Devices
 * CS 327 - Design Project, Fall 2002
 * University of Illinois, Urbana-Champaign
 * 
 * file: FrameTrigger.java 
 * contact: Braden Kowitz
 * date: 11/24/02
 **/

//----------------------------------------------------------------------------//

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


/**
 * This trigger is responsible for calling advanceFrame() on a GrameCanvas
 * object.
 **/
public class FrameTrigger extends Thread
{

	/**
	 * The GameCanvas where we call advanceFrame.
	 **/
	GameCanvas game_;	
	
	/**
	 * Time is miliseconds between frames
	 **/
	private int frameDelay_;

	/**
	 * Value which is true if the thread is to be stopped.
	 **/
	private boolean stopped;

	/**
	 * Constructor
	 * @param g Canvas for wich to trigger frame updates.
	 * @param frameDelay time in MS between frame updates.
	 **/
	public FrameTrigger(GameCanvas g, int frameDelay)
	{
		game_ = g;
		frameDelay_ = frameDelay;
		stopped = true;
	}

	/**
	 * Stops the trigger from functioning.
	 * (stops execution of the thread)
	 **/
	public void stopTrigger()
	{ stopped = true; }
	
	/**
	 * starts the trigger
	 */
	public void startTrigger()
	{ stopped = false; }

	/**
	 * Starts the trigger running.
	 * - To be called by the thead start() function call.
	 **/
	public void run()
	{
		//stopped=false; // having this might cause problems
		while (!stopped)
		{	
			game_.advanceFrame();
			try {
                    		sleep(frameDelay_);
                	} catch (InterruptedException ie) {}
		}
		System.out.println("FrameTrigger Thread Stopped");
	}

}
//----------------------------------------------------------------------------//