e7_5.java

来自「java 初学者学习实例」· Java 代码 · 共 41 行

import java.applet.*;
import java.awt.*;
import java. awt. event. *;
public class E7_5 extends Applet implements KeyListener
{Button b=new Button("我能被移动");
  int b_x=0, b_y=0;
 public void init()
  {b. addKeyListener (this);  
   setLayout (null);
   add(b);
   b.setBounds(20, 20,70, 30);
   b_x=b.getBounds() .x;b_y=b.getBounds() .y; 
  }
 public void keyTyped(KeyEvent e)
  {
  }
 public void keyPressed(KeyEvent e)
 {if (e.getKeyCode ( ) ==KeyEvent .VK_UP)
       {b_y=b_y-2;
         if (b_y<=0) b_y=0;
         b.setLocation(b_x, b_y);
       }
 else if(e.getKeyCode()==KeyEvent.VK_DOWN)
       {b_y=b_y+2;
         if(b_y>=300) b_y=300;
         b.setLocation(b_x, b_y);
       }
	   else if (e .getKeyCode ( ) ==KeyEvent .VK_LEFT)
      { b_x=b_x- 2;
       if(b_x<=0) b_x=0;
       b.setLocation(b_x, b_y);
    }
else if ( e. getKeyCode ( ) ==KeyEvent. VK_RIGHT)
      { b_x=b_x+ 2;
       if (b_x>=300) b_x=300;
       b. setLocation(b_x, b_y);
    }
}
public void keyReleased(KeyEvent e)
{}
}