handlemouseevent.java

java小游戏代码

// 程序：处理鼠标事件
// 范例文件：HandleMouseEvent.java

import java.awt.*;
import java.applet.*;
import java.awt.event.*;   //为了处理事件

//除了Runnable之外，还实现了MouseListener及MouseMotionListener
public class HandleMouseEvent extends Applet 
             implements Runnable,MouseListener,MouseMotionListener
{
   int          AppletWidth,AppletHeight,hammerX,hammerY,
                hammerWidth,hammerHeight,clickCount;
   Image        hammer1,hammer2,OffScreen,currentHammer;
   Thread       newThread;
   boolean      showHammer;
   Graphics     drawOffScreen;
   MediaTracker MT;

   public void init()
   {  
      addMouseListener(this);            //注册事件处理方法
      addMouseMotionListener(this);   

      setBackground(Color.gray);         //设定背景颜色
    
      AppletWidth  = getSize().width;    //取得Applet的高度
      AppletHeight = getSize().height;   //取得Applet的宽度
      clickCount   = 0;                  //mouseClick事件发生的次数
      
      //取得铁锤图像
      hammer1      = getImage(getDocumentBase(),"Images/hammer1.gif");
      hammer2      = getImage(getDocumentBase(),"Images/hammer2.gif");

      MT           = new MediaTracker(this); 
      MT.addImage(hammer1,0);
      MT.addImage(hammer2,0);
      
      try
      {
         showStatus("图像加载中(Loading Images)...");
         MT.waitForAll();
      }
      catch(InterruptedException E){ }   //没有进行异常处理
      
      hammerWidth   = hammer1.getWidth(this);   //取得铁锤图像宽度
      hammerHeight  = hammer1.getHeight(this);  //取得铁锤图像高度
      currentHammer = hammer1;                  //使用铁锤图像1
      showHammer    = false;                    //先不显示铁锤

      //建立次画面
      OffScreen     = createImage(AppletWidth,AppletHeight);
      drawOffScreen = OffScreen.getGraphics();
   }

   public void start()                   //start()方法  
   {
      newThread = new Thread(this);      //建立与启动新线程
      newThread.start();
   }

   public void stop()                    //stop()方法
   {
      newThread = null;                  //将线程设为null
   }

   public void paint(Graphics g)
   {
      //清除次画面
      drawOffScreen.clearRect(0,0,AppletWidth,AppletHeight);

      //绘制铁锤图像
      if(showHammer)
         drawOffScreen.drawImage(currentHammer,hammerX,hammerY,this);

      //将次画面贴到主画面中
      g.drawImage(OffScreen,0,0,this);
   }

   public void update(Graphics g)        //update()方法
   {
      paint(g);                          //只单纯调用paint()方法
   }
   
   public void run()
   {  
      while(newThread != null)           //动画循环
      {  
         repaint();                      //重新绘制图像

         try
         {
            Thread.sleep(80);            //暂停程序执行80毫秒
         }
         catch(InterruptedException E){ }//没有进行异常处理
      }
   }

   //=====实现MouseListener界面========================================
   public void mouseExited(MouseEvent e)      //鼠标离开Component
   {
      if(showHammer) showHammer = false;      //不绘制铁锤
   }

   public void mouseClicked(MouseEvent e)     //鼠标按键被按下后放开
   {
      showStatus("挥动铁锤" + (++clickCount) + "次");
   }

   public void mouseEntered(MouseEvent e)     //鼠标进入Component
   {
      if(!showHammer) showHammer = true;      //绘制铁锤
   }

   public void mousePressed(MouseEvent e)     //鼠标按键被按下
   {
      currentHammer = hammer2;                //绘制铁锤图像2
   }

   public void mouseReleased(MouseEvent e)    //鼠标按键放开
   {
      currentHammer = hammer1;                //绘制铁锤图像1
   }

   //=====实现MouseMotionListener界面==================================
   public void mouseMoved(MouseEvent e)       //鼠标移动时
   {
      //设定铁锤图像的坐标
      hammerX = e.getX() - (hammerWidth / 2);
      hammerY = e.getY() - (hammerHeight / 2);

      //碰到边界时的状态
      if(hammerX <= 0) 
         hammerX = 0;
      if(hammerX >= (AppletWidth - hammerWidth))
         hammerX = AppletWidth - hammerWidth;
      if(hammerY <= 0)
         hammerY = 0;
      if(hammerY >= (AppletHeight - hammerHeight))
         hammerY = AppletHeight - hammerHeight;

      showStatus("(" + hammerX + "," + hammerY + ")");
   }  
 
   public void mouseDragged(MouseEvent e)     //鼠标拖曳时 
   {
      //设定铁锤图像的坐标
      hammerX = e.getX() - (hammerWidth / 2);
      hammerY = e.getY() - (hammerHeight / 2);

      //碰到边界时的状态
      if(hammerX <= 0) 
         hammerX = 0;
      if(hammerX >= (AppletWidth - hammerWidth))
         hammerX = AppletWidth - hammerWidth;
      if(hammerY <= 0)
         hammerY = 0;
      if(hammerY >= (AppletHeight - hammerHeight))
         hammerY = AppletHeight - hammerHeight;

      showStatus("(" + hammerX + "," + hammerY + ")");
   }
}