简单的弹球游戏
该程序主要是用于对java图形化界面编程进行联系，程序实现全部采用的是AWT包下的类。
程序仅做参考，供学习使用。

import java.awt.Canvas;
import java.awt.Color;
import java.awt.Dimension;
import java.awt.Font;
import java.awt.Frame;
import java.awt.Graphics;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.KeyAdapter;
import java.awt.event.KeyEvent;
import java.awt.event.KeyListener;
import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;

import javax.swing.Timer;

public class PinBallGame {
	//创建窗口对象
	private Frame frame = new Frame("弹球游戏");
	
	//桌面宽度
	private final int TABLE_WTDTH = 300;
	//桌面高度
	private final int TABLE_HEIGHT = 400;
	
	//球拍的高度和宽度
	private final int RACKET_WIDTH = 60;
	private final int RACKET_HETGHT = 20;
	
	//小球的大小
	private final int BALL_SIZE = 16;
	
	//定义变量，记录小球的坐标
	private int ballX = 120;
	private int ballY = 20;
	
	//定义变量，记录小球在x和y方向上分别移动的速度
	private int speedY = 10;
	private int speedX = 5;
	
	//定义变量，记录球拍的坐标
	private int racketX = 120;
	private final int racketY = 340;
	
	//定义变量，标识当前游戏是否已结束
	private boolean isOver = false;
	
	//声明一个定时器
	private Timer timer;
	
	//自定义一个类，继承Canvas，充当画布
	@SuppressWarnings("serial")
	private class MyCanvas extends Canvas{
		
		@Override
		public void paint(Graphics g) {
			//TODO 在这里绘制内容
			if (isOver) {
				//游戏结束
				g.setColor(Color.BLUE);
				g.setFont(new Font("Times",Font.BOLD,30));
				g.drawString("游戏结束！", 50, 200);
				
			}else{
				//游戏中
				//绘制小球
				g.setColor(Color.RED);
				g.fillOval(ballX, ballY, BALL_SIZE, BALL_SIZE);
				//绘制球拍
				g.setColor(Color.PINK);
				g.fillRect(racketX, racketY, RACKET_WIDTH, RACKET_HETGHT);
			}
		}
	}
	
	//创建绘画区域
	MyCanvas drawArea = new MyCanvas();
	
	public void init() {
		//组装视图，游戏逻辑的控制
		//完成球拍坐标的变化
		KeyListener listener = new KeyAdapter() {
			
			@Override
			public void keyPressed(KeyEvent e) {
				//获取当前按下的键
				int keyCode = e.getKeyCode();
				if (keyCode == KeyEvent.VK_LEFT) {
					//<- 应该向左移动
					if (racketX>0) {
						racketX -= 10;
					}
				}
				
				if (keyCode == KeyEvent.VK_RIGHT) {
					//-> 应该向右移动
					if (racketX <(TABLE_WTDTH - RACKET_WIDTH)) {
						racketX += 10;
					}
				}
			}
		};
		
		//给Frame和drawArea注测监听器
		frame.addKeyListener(listener);
		drawArea.addKeyListener(listener);
		
		//小球坐标的控制
		ActionListener task = new ActionListener() {
			
			@Override
			public void actionPerformed(ActionEvent arg0) {
				//根据边界范围，修正速度
				if (ballX<=0 || ballX>=(TABLE_WTDTH-BALL_SIZE)) {
					speedX = -speedX;
				}
				
				if (ballY <= 0 || (ballY > racketY-BALL_SIZE && ballX>racketX && ballX < racketX+RACKET_WIDTH)) {
					speedY = -speedY;
				}
				
				if (ballY > racketY-BALL_SIZE && (ballX < racketX || ballX > racketX+RACKET_WIDTH)) {
					//当前小球超出了球拍的范围，游戏结束
					//停止定时器
					timer.stop();
					//修改游戏是否结束的标记
					isOver = true;
					//重绘界面
					drawArea.repaint();
				}
				
				//更新小球的坐标，重绘界面
				ballX += speedX;
				ballY += speedY;
				//重绘界面
				drawArea.repaint();
			}
		};
		
		timer = new Timer(100, task);
		timer.start();
		
		drawArea.setPreferredSize(new Dimension(TABLE_WTDTH,TABLE_HEIGHT));
		frame.add(drawArea);
		
		//设置frame最佳大小，并可视
		frame.pack();
		frame.setVisible(true);
		frame.setLocationRelativeTo(null);
		
		frame.addWindowListener(new WindowAdapter() {
			
			@Override
			public void windowClosing(WindowEvent e) {
				System.exit(0);
			}
		});
	}

	public static void main(String[] args) {
		new PinBallGame().init();
	}
}