ai1.java

几个JAVA applet的例子

// 程序：角色追踪移动
// 范例文件：AI1.java

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

class Sprite
{
   int spriteX,spriteY,VX,VY;
   AI1 Game;
   Image    UFO, Beast;

   public Sprite(Image UFO, Image Beast,AI1 Game)
   {
      this.Game = Game; 
      this.UFO = UFO;
      this.Beast = Beast;

      spriteX   = 0;
      spriteY   = 0;
      VX        = 0;
      VY        = 0;
   }

   public void updateState()
   {
      if(spriteX + 25 > Game.getX())
         VX = -1;
      else if(spriteX + 25 < Game.getX())
         VX = 1;
      else
         VX = 0;

      if(spriteY + 25 > Game.getY())
         VY = -1;
      else if(spriteY + 25 < Game.getY())
         VY = 1;
      else
         VY = 0;

      spriteX = spriteX + VX;
      spriteY = spriteY + VY;
   }

   public void paintSprite(Graphics g)
   {  
      g.drawImage(Beast,spriteX,spriteY,80,80,Game);
      g.drawImage(UFO,Game.getX(),Game.getY(),50, 50,Game);
   }
}

public class AI1 extends Applet 
       implements Runnable,MouseListener,MouseMotionListener
{
   int      mouseX,mouseY,AppletWidth,AppletHeight;   
   Image    OffScreen, UFO, Beast;
   Thread   newThread; 
   Graphics drawOffScreen;
   boolean  update;
 
   Sprite   S;

   public void init()
   {
      mouseX       = 0;
      mouseY       = 0;
      AppletWidth  = getSize().width;
      AppletHeight = getSize().height;
      update       = false;


      UFO   = getImage(getDocumentBase(),"Images/6.gif");
      Beast      = getImage(getDocumentBase(),"Images/1.gif");
      S            = new Sprite(UFO,Beast,this); 

      addMouseListener(this);     
      addMouseMotionListener(this);


      OffScreen      = createImage(AppletWidth,AppletHeight);
      drawOffScreen  = OffScreen.getGraphics();
   }

   public void start()         
   {
      newThread = new Thread(this);    
      newThread.start();
   }

   public void stop()        
   {
      newThread = null;      
   }

   public void paint(Graphics g)
   {
      drawOffScreen.clearRect(0,0,AppletWidth,AppletHeight);

      S.paintSprite(drawOffScreen);
           
      g.drawImage(OffScreen,0,0,this); 
   }

   public void update(Graphics g)     
   {
      paint(g);                       
   }

   public void run()
   {
      while(newThread != null)
      {
         repaint();           

         try
         {
            Thread.sleep(33);   
         }
         catch(InterruptedException E){ }

         if(update)
            S.updateState();   
      }
   }

   public int getX() 
   {
      return mouseX;
   }

   public int getY()  
   {
      return mouseY;
   }

   public void mouseExited(MouseEvent e) 
   {
      update = false;                  
   }
   
   public void mouseClicked(MouseEvent e){} 
   
   public void mouseEntered(MouseEvent e) 
   {
      update = true;          
   }
   
   public void mousePressed(MouseEvent e){}  
   
   public void mouseReleased(MouseEvent e){}
  
   public void mouseMoved(MouseEvent e)  
   {
      mouseX = e.getX();     
      mouseY = e.getY();    
      showStatus("(" + mouseX + "," + mouseY + ")");
   }  
 
   public void mouseDragged(MouseEvent e){} 
}