gameapplet.java

本代码为java编写的泡泡龙游戏

import java.applet.*;
import java.awt.*;
import java.awt.event.*;

/**
 * A time-managed version of the Applet class. 
 */

public abstract class GameApplet extends Applet implements Runnable, KeyListener, MouseListener, MouseMotionListener 
{
	//定义的一个静态成员，决定处理事件的时间间隔
    protected static long REFRESH_RATE_MILLIS = 25;
	
	//内存缓存图片，以克服抖动
    private Graphics gBack;
    private Image iBack;
	
	//保存当前的屏幕对象
    private GameScreen currentScreen;
    //保存当前的上下文对象
    private GameContext currentContext;
    //保存游戏媒体加载器对象
    private GameMedia currentMedia;
	//保存SUN音频管理器对象
    private SunAudioManager sunAudio;
	//保存游戏的宽度与高度
    private int gameWidth, gameHeight;
	//标志游戏是否在运行，子线程是否在运行
    private boolean gameRunning, threadRunning;
	
	//保存按键事件列表
    private int[] listKeys;
    //保存鼠标的位置
    private Point mousePosition;
    //保存鼠标左键的状态
    private boolean leftMouseButtonState;
    //保存鼠标右键的状态
    private boolean rightMouseButtonState;	
	
	//标识游戏的运行状态
    private boolean isApplication = false;
    
    //初始化Applet
    public void init() 
    {
    	//得到Applet的宽度与高度
		gameWidth = this.getSize().width;
		gameHeight = this.getSize().height;
		
		//创建与Applet同大小的内存缓存图片对象
		iBack = this.createImage(gameWidth, gameHeight);
		gBack = iBack.getGraphics();
		
		//创建游戏上下文对象
		currentContext = new GameContext();
		//创建游戏媒体加载器对象
		currentMedia = new GameMedia(this);
			
		try 
		{		//创建SUN音频管理器对象
	            sunAudio = new SunAudioManager(this);
		}
		catch(Exception e) 
		{
	            System.err.println("Package sun.audio is not available");
		}
		
		//调用派生类中的gameInit()，初始化游戏资源
		gameInit();
		//设置游戏当前的屏幕
		setCurrentScreen(this.getInitialScreen());
			
		listKeys = new int[0];
		mousePosition = new Point(0, 0);
		
		//注册键盘按键事件处理器
		if (needsKeyEvents()) 
		{
	         addKeyListener(this);		
		}
		//注册鼠标事件处理器
		if (needsMouseEvents()) 
		{
	         addMouseListener(this);
	         addMouseMotionListener(this);
		}
    }
    //抽象函数，用于得到初始的游戏屏幕
    public abstract GameScreen getInitialScreen();
	//抽象函数，用于初始化游戏
    public abstract void gameInit();
    
    // 调协游戏为应用程序方式运行
    public void setAsApplication() 
    {
        this.isApplication = true;
    }
    //得到游戏运行的方式
    public boolean isApplication() 
    {
        return this.isApplication;
    }
    //得到游戏声音管理器对象
    public SunAudioManager getSunAudioManager()	
    {
		return sunAudio;
    }
	//得到是否需要注册键盘事件处理器
    public boolean needsKeyEvents() 
    {
		return true;
    }
	//得到是否需要注册鼠标事件处理器
    public boolean needsMouseEvents() 
    {
  		return true;
    }
	//得到游戏的宽度
    public final int getWidth()	
    {
		return gameWidth;
    }
	//得到游戏的高度
    public final int getHeight() 
    {
		return gameHeight;
    }
	//得到游戏的内存缓存图片
    public final Image getBackgroundImage() 
    {
		return iBack;
    }
	//得到游戏的内存缓存图片对应的画笔
    public final Graphics getBackgroundGraphics() 
    {
		return gBack;
    }
	//得到游戏的上下文对象
    public final GameContext getGameContext() 
    {
		return currentContext;
    }
	//得到游戏的媒体加载器对象
    public final GameMedia getGameMedia() 
    {		
		return currentMedia;
    }
	
	//设置游戏的当前屏幕
    public final void setCurrentScreen(GameScreen newCurrentScreen) 
    {
		currentScreen = newCurrentScreen;
		currentScreen.initBackground();
    }
	//启动线程
    public final void start() 
    {
		while (threadRunning);
			
		gameRunning = true;		
			
		new Thread(this).start();		
    }
	//停止线程
    public final void stop() 
    {
		gameRunning = false;
    }
	//这是子线程的代码
    public final void run() //Applet主类是用来捕获用户的输入的，并且每隔25毫移就处理一次事件
    {
		long time;
	
		threadRunning = true;
			
		while(gameRunning) 
		{
			//得到事件处理前一刻的时间
            time = System.currentTimeMillis();
			
			//调用当前屏幕的play进行事件处理			
            currentScreen.play(listKeys, mousePosition, leftMouseButtonState, rightMouseButtonState);
            //从内存缓存图片中清除所有显示的精灵
            currentScreen.refreshAll();
            //重新显示所有的精灵
            currentScreen.paintAll();
			//得到处理事件消耗的时差
            time = System.currentTimeMillis()-time;
			
			//保证最少隔25毫秒才处理一次事件
            if (time < this.REFRESH_RATE_MILLIS) 
            {
				try 
				{
		             Thread.sleep(this.REFRESH_RATE_MILLIS - time);
				}
				catch(Exception e) {
		             System.err.println("[Thread] - Unable to sleep");		
				}
            }
			
            if (gameRunning) {
				paint(this.getGraphics());
            }
		}
			
		threadRunning = false;
    }
	
	//显示游戏
    public final void paint(Graphics g)	
    {
        if (iBack != null) 
        {
            g.drawImage(iBack, 0, 0, this);
        }
    }
    
	 //处理键盘按下事件
    public final void keyPressed(KeyEvent e) 
    {
		int currentKey = e.getKeyCode();
			
		if (currentKey == 18) 
		{
	            return;
		}
		//将按键的键码保存到数组中
		if (listKeys.length != 0)
		{
            if (listKeys[0] != currentKey) 
            {
				int[] newListKeys = new int[listKeys.length+1];
						
				newListKeys[0] = currentKey;
				for (int i=0 ; i<listKeys.length ; i++) 
				{
		             newListKeys[i+1] = listKeys[i];
				}
						
				listKeys = newListKeys;
            }
		}
		else 
		{
            listKeys = new int[1];
            listKeys[0] = currentKey;
		}
    }
	 //处理键盘释放事件
    public final void keyReleased(KeyEvent e) 
    {
		int currentKey = e.getKeyCode();
		
		//从数组中删除按键的键码
		if (listKeys.length != 0)
		{
            int[] newListKeys = new int[listKeys.length-1];
            boolean found = false;
			
            for (int i=0 ; i<listKeys.length ; i++) 
            {
                if (found) 
                {
                    newListKeys[i-1] = listKeys[i];
		        }
		        else 
		        {
                    if (i != listKeys.length - 1) 
                    {
			            newListKeys[i] = listKeys[i];
                    }
		        }
				
		       if (listKeys[i] == currentKey) 
		       {
                    found = true;
		       }
				
		       if (i == listKeys.length-1 && !found) 
		       {
                    return;
		       }					
            }
			
            listKeys = newListKeys;
	     }
    }
	
    public final void keyTyped(KeyEvent e) {}

    public final void mouseClicked(MouseEvent e) {}
    
    //处理鼠标进入事件
    public final void mouseEntered(MouseEvent e) 
    {
		mousePosition = e.getPoint();
			
		paint(this.getGraphics());
    }
    
	//处理鼠标退出事件
    public final void mouseExited(MouseEvent e) 
    {
		mousePosition = e.getPoint();
			
		paint(this.getGraphics());
    }
    
	//处理鼠标按下事件
    public final void mousePressed(MouseEvent e) 
    {
		mousePosition = e.getPoint();
				
		int buttons = e.getModifiers();//System.out.println("x:"+mousePosition.getX()+"\ty:"+mousePosition.getY());	
		
		if ((buttons & MouseEvent.BUTTON1_MASK) == MouseEvent.BUTTON1_MASK) {
	            leftMouseButtonState = !leftMouseButtonState;
		}
			
		if ((buttons & MouseEvent.BUTTON3_MASK) == MouseEvent.BUTTON3_MASK) {
	            rightMouseButtonState = !rightMouseButtonState;
		}
			
		paint(this.getGraphics());
    }
	//处理鼠标释放事件
    public final void mouseReleased(MouseEvent e) 
    {
		mousePosition = e.getPoint();
	
		
		int buttons = e.getModifiers();
			
		if ((buttons & MouseEvent.BUTTON1_MASK) == MouseEvent.BUTTON1_MASK) {
	            leftMouseButtonState = !leftMouseButtonState;
		}
			
		if ((buttons & MouseEvent.BUTTON3_MASK) == MouseEvent.BUTTON3_MASK) {
	            rightMouseButtonState = !rightMouseButtonState;
		}
			
		paint(this.getGraphics());
    }
	
	//处理鼠标拖动事件
    public final void mouseDragged(MouseEvent e) 
    {
		mousePosition = e.getPoint();
			
		paint(this.getGraphics());
    }
	
	//处理鼠标移动事件
    public final void mouseMoved(MouseEvent e) 
    {
		mousePosition = e.getPoint();
			
		paint(this.getGraphics());
    }	
}