JAVA 开发实例 一 移动的小球

package com.java.move;

import java.awt.Color;
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.GraphicsConfiguration;
import java.awt.HeadlessException;
import java.awt.Toolkit;
import java.awt.event.KeyAdapter;
import java.awt.event.KeyEvent;

import javax.swing.*;

/*
 *
 * author : deng_hui_long 
 * Date   : 2013-10-16
 *
 */
public class TextMove extends JFrame {
	private int width = 500;// 窗口的宽度
	private int height = 500;// 宽口的高度
	private Toolkit took = null;// 将各个组件绑定
	private TextPanel textPanel = null;

	public static void main(String[] args) {
		new TextMove().show();
	}

	public TextMove() {
		setTitle("移动的小球");
		took = Toolkit.getDefaultToolkit();
		Dimension dm = took.getScreenSize();// 获取屏幕的 宽度和高度
		int swidth = (dm.width - this.width) / 2;
		int sheight = (dm.height - this.height) / 2;
		setLocation(swidth, sheight);// 窗口居于屏幕中间
		setSize(width, height);// 设置窗体的大小
		setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);// 关闭
		textPanel = new TextPanel(10, 10);// 面板
		add(textPanel);// 添加面板
		addKeyListener(new Keyent());// 添加键盘事件
	}

	// 键盘事件
	class Keyent extends KeyAdapter {
		@Override
		public void keyPressed(KeyEvent e) {
			if (e.getKeyCode() == KeyEvent.VK_UP) {// 上
				textPanel.y -= 5;
			} else if (e.getKeyCode() == KeyEvent.VK_DOWN) {// 下
				textPanel.y += 5;
			} else if (e.getKeyCode() == KeyEvent.VK_LEFT) {// 左
				textPanel.x -= 5;
			} else if (e.getKeyCode() == KeyEvent.VK_RIGHT) {// 右
				textPanel.x += 5;
			}
			textPanel.repaint();// 重新绘图
		}
	}

	// 继承面板在面板上绘图
	class TextPanel extends JPanel {// 继承面板
		int x;
		int y;

		public TextPanel(int x, int y) {
			this.x = x;
			this.y = y;
		}

		public void paint(Graphics g) {// 在面板上绘图
			super.paint(g);
			g.setColor(Color.black);// 设置画笔的颜色
			g.fillOval(x, y, 20, 20);// 画圆
		}
	}
}