mycanvas.java

用JAVA APPLET开发的小游戏,介绍了鼠标和键盘的事件响应,是初学JAVA EVENT LISTENER 的例子教程.

import java.awt.*;
import java.awt.event.*;
import java.util.Vector;

public class mycanvas extends Canvas
implements MouseListener,Runnable
{   public int num=0,eatnum=0;
    Vector v1;                 //用v1存放全部movecircle对象
    Thread t1;
    int status=0;              //当status=1时,movecircle对象才显示
    datacanvas dc1;
       
    int firststep,step=60;        //firststep是卡通的起始位置,step是卡通的长度
        
    mycanvas(datacanvas a)
    {   dc1=a;
        v1=new Vector();   
        t1=new Thread(this); 
        t1.start();
        setBackground(Color.lightGray);
    }
     
  /*  public void getimage(Image im)
    { im1=im;
    }*/
    
    public void paint(Graphics g)
    {   
        g.drawRect(0,0,getWidth()-1,getHeight()-1); 
        g.fill3DRect(firststep,360,step,40,true);
        
        if(status==1)
           {for(int i=0;i<v1.size();i++)
        	   {  
        	      movecircle c1=(movecircle)v1.elementAt(i);
        	      c1.draw(g);          	   
               }
           }

  //      g.drawString("all :"+Thread.currentThread().activeCount()+" name:"+Thread.currentThread().getName(),200,200);      
        g.setColor(Color.black);
       
    }
    
public void run()
{  while(true){
       try{  
    
       for(int i=0;i<num;i++){  
         movecircle c1=(movecircle)v1.elementAt(i);
         if(c1.x<firststep+step & c1.x>firststep & c1.y>360)            //在x轴的(firststep,firststep+step)区域把球吃掉  
         {  c1.stop();                    //thread stop
            v1.removeElementAt(i);
            i=i-1;
            num--;
            eatnum++;          	  
          }   
        }	
        
        dc1.setmessage(num,eatnum);
        repaint();
        Thread.sleep(100);  
        
               }
       catch(Exception e)
       {} 
  }
}    

  /*  public void run()
    {  String str;
           
  while(true){
  	   str=Thread.currentThread().getName();           //拿出当前的线程名称
       try{ 
    for(int i=0;i<thnum;i++){
    	
    	 if(str.equalsIgnoreCase("th"+i))
    	 {  
    	     movecircle c1=(movecircle)v1.elementAt(i);
        	 if(c1.x<firststep+step & c1.x>firststep & c1.y>360)            //在x轴的(firststep,firststep+step)区域把球吃掉  
        	     {  v1.removeElementAt(i);
        	        i=i-1;
        	        num--;
        	        eatnum++;
        	     	t3[i].stop();
        	  
        	      }
        	 else
        	      {c1.move();}
        	     	 
    	 }
    }
  //  t3[2].stop();
    	 repaint();
         Thread.sleep(100);
       }
       catch(Exception e)
       {}    
  }
    }
    
*/   
    
    public void mousePressed(MouseEvent e)
    { if(num<30)                                         //球的数目<30
       {num=num+1;
        double a=Math.floor(Math.random()*10);           //算出随机数0=<a,b<=10
        double b=Math.floor(Math.random()*10);  
         
        movecircle c2=new movecircle(e.getX(),e.getY(),(int)(Math.pow(-1,a)*a),(int)(Math.pow(-1,b)*b),10);    	
        v1.addElement(c2);
        c2.start();        //thread start
        repaint();

       }
       status=1;     
    }
    
    
       
    public void mouseEntered(MouseEvent e)
    {
        setCursor(Cursor.getPredefinedCursor(Cursor.HAND_CURSOR));
    }
    public void mouseClicked(MouseEvent e){}
    public void mouseExited(MouseEvent e){}
    public void mouseReleased(MouseEvent e){}    
    
    
    public void setstep(int first,int a)
    {  
       if(a<8)
         firststep=first;//-(500-384)/2;
       else if(a<11)
         firststep=first+20;
       else
         firststep=first+50;
    }    
    
    public void threadstop()
    {  for(int i=0;i<num;i++){  
         movecircle c1=(movecircle)v1.elementAt(i);
         c1.stop();         
       }
       
       v1.removeAllElements();
   }
    public void initball()
    {   num=0;
        eatnum=0;
        
    }
    
}