e9_2.java

java 初学者学习实例

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

 public class E9_2 extends Applet implements Runnable
{ Thread left , right; Graphics mypen; int x, y;
   public void init()
  { left=new Thread(this);right=new Thread(this);
    x=10;y=10;mypen=getGraphics();
  }
 public void start()
  {left.start();right.start();
  }
 public void run()
  { while(true)
    if(Thread.currentThread()==left)
      { x=x+1;
        if(x>240) x=10;
        mypen.setColor(Color.blue);
        mypen.clearRect(10, 10, 300, 100);
        mypen.drawRect(10+x, 10, 50, 50);
             try{left.sleep(60);     }
       catch(InterruptedException e){}
     }
  else if (Thread. currentThread ( ) ==right )
     { y=y+1;
       if(y>240) y=10; mypen.setColor(Color.red);
      mypen.clearRect(10, 110, 300, 100);
      mypen.drawOval(10+y, 110, 50, 50);
       try{right.sleep(60);     }
       catch(InterruptedException e){}
     }
  }
public void stop()
   {left=null;right=null;
   }
}