练习.键盘控制小球

 1 package com.java7.keyboardcontrolmyball.main;
 2 import java.awt.*;
 3 import java.awt.event.*;
 4 
 5 public class KeyboardControlMyBall {
 6     public static void main(String[] args) {
 7         Frame w = new Frame();
 8         w.setSize(300,400);
 9         
10         MyPanel mp = new MyPanel();
11         w.add(mp);
12         
13         w.addKeyListener(mp);
14         mp.addKeyListener(mp);
15         
16         w.show();
17     }
18 }
19 
20 class MyPanel extends Panel implements KeyListener {
21     int x = 30;
22     int y = 30;
23     public void paint(Graphics g) {
24         g.fillOval(x, y, 20, 20);
25     }
26 
27     @Override
28     public void keyPressed(KeyEvent arg0) {
29         if(arg0.getKeyCode() == 37) {
30             x--;
31         }
32         if(arg0.getKeyCode() == 38) {
33             y--;
34         }
35         if(arg0.getKeyCode() == 39) {
36             x++;
37         }
38         if(arg0.getKeyCode() == 40) {
39             y++;
40         }
41 //        System.out.println(arg0.getKeyCode());
42         repaint();
43     }
44     @Override
45     public void keyReleased(KeyEvent e) {
46     }
47     @Override
48     public void keyTyped(KeyEvent e) {
49         
50     }
51 }