/**
* 功能是加深对事件处理机制的理解
* 1：通过上下左右键来控制小球为位置的移动
*/
package com.test4;
import java.awt.*;
import javax.swing.*;
import java.awt.event.*;
public class Demo9_4 extends JFrame {
MyPanel mp=null;
public static void main(String[] args) {
// TODO Auto-generated method stub
Demo9_4 demo=new Demo9_4();
}
//构造函数
public Demo9_4()
{
mp=new MyPanel();
//mp加入到JFrame
this.add(mp); // 每定义一个 Demo9_4 都会产生一个对应的this
//添加监听
this.addKeyListener(mp); // 键盘监听这个类所定义的对象 用mp对象进行监听
this.setSize(400,300);
this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
this.setVisible(true);
}
}
//定义自己的面板
class MyPanel extends JPanel implements KeyListener
{
int x=10;
int y=10;
public void paint(Graphics g)
{
super.paint(g);
g.setColor(Color.BLUE);
g.fillOval(x, y, 20, 20);
}
//键被按下
public void keyPressed(KeyEvent arg0) {
// TODO Auto-generated method stub
// System.out.println("键被按下"+(char)arg0.getKeyCode() );
if(arg0.getKeyCode()==KeyEvent.VK_UP)
{
//System.out.println("键被按上");
y-=10;
}
if(arg0.getKeyCode()==KeyEvent.VK_DOWN)
{
//System.out.println("键被按上");
y+=10;
}
if(arg0.getKeyCode()==KeyEvent.VK_LEFT)
{
//System.out.println("键被按左");
x-=10;
}
if(arg0.getKeyCode()==KeyEvent.VK_RIGHT)
{
//System.out.println("键被按右");
x+=10;
}
//调用 repaint() 函数，来重绘制界面
this.repaint();
}
//键被释放
public void keyReleased(KeyEvent arg0) {
// TODO Auto-generated method stub
}
//键的一个值被打印输出
public void keyTyped(KeyEvent arg0) {
// TODO Auto-generated method stub
}
}