《Oracle Java SE编程经典案例》01：桌面弹球

1、介绍

本案例中使用的知识点如下：

• GUI

• 线程

• 单例模式

• 面向对象六大原则

2、案例代码

2.1、球体

/**
 * 主题：球体
 * 作者：AT阿宝哥
 * 时间：2016年8月24日
 * 描述：
 * 		
 * 			
 * 注意：
 * 		
 */
package com.company.project.sample.s01;

import java.awt.Color;
import java.awt.Graphics;
import java.awt.event.MouseEvent;
import java.awt.event.MouseListener;
import java.util.Random;

import javax.swing.JPanel;

//类：球体
public class Ball extends JPanel implements Runnable, MouseListener {
	// 定义球体编号
	private String id;

	// 定义球体在“球桌”里的x,y坐标
	private int x;
	private int y;

	// 定义球体在x,y方向的可移动的范围
	private int deskWidth;
	private int deskHeight;

	// 定义球体移动的方向
	private String direction;

	// 定义球体颜色
	private Color ballColor;

	// 定义球体移动开关
	private boolean canMove;

	// 构造方法
	public Ball(String id, int deskWidth, int deskHeight, Color deskBackColor) {
		super();
		this.id = id;
		this.x = new Random().nextInt(deskWidth);
		this.y = new Random().nextInt(deskHeight);
		this.deskWidth = deskWidth;
		this.deskHeight = deskHeight;

		// 随机产生运动方向
		changeDirection();

		// 注册监听器
		this.addMouseListener(this);

		// 设置球体颜色
		this.ballColor = new Color((int) (Math.random() * 255), (int) (Math.random() * 255),
				(int) (Math.random() * 255));

		// 设置球体可移动
		this.canMove = true;

		// 设置面板背景色
		this.setBackground(deskBackColor);

		// 设置面板初始位置和大小
		this.setBounds(x, y, 50, 50);
	}

	// 重写方法：线程体
	@Override
	public void run() {
		System.out.println(id + "已启动...");
		while (true) {
			if (canMove) {
				move();
			} else {
				break;
			}
			try {
				Thread.sleep(5);
			} catch (InterruptedException e) {
				e.printStackTrace();
			}
		}
		System.out.println(id + "已结束...");
	}

	// 方法：球体移动
	private void move() {

		// 记录原来的方向
		String originalDirection = direction;
		
		// 判断并设置移动方向
		if (y <= 0) {
			// 移动到“----上边----”的情况
			if (originalDirection == "左上") {
				direction = "左下";
			} else if (originalDirection == "右上") {
				direction = "右下";
			}

		}
		if (x >= this.deskWidth - this.getSize().width) {
			// 移动到“----右边----”的情况
			if (originalDirection == "右上") {
				direction = "左上";
			} else if (originalDirection == "右下") {
				direction = "左下";
			}

		}
		if (y >= this.deskHeight - this.getSize().height) {
			// 移动到“----下边----”的情况
			if (originalDirection == "左下") {
				direction = "左上";
			} else if (originalDirection == "右下") {
				direction = "右上";
			}

		}
		if (x <= 0) {
			// 移动到“----左边----”的情况
			if (originalDirection == "左下") {
				direction = "右下";
			} else if (originalDirection == "左上") {
				direction = "右上";
			}

		}
		switch (direction) {
		case "右下":
			this.setLocation(x++, y++);
			break;
		case "左下":
			this.setLocation(x--, y++);
			break;
		case "左上":
			this.setLocation(x--, y--);
			break;
		case "右上":
			this.setLocation(x++, y--);
			break;
		default:
			break;
		}
	}

	// 重写方法：重绘圆形
	@Override
	public void paintComponent(Graphics g) {
		super.paintComponent(g);

		g.setColor(ballColor);
		g.fillOval(0, 0, 50, 50);
		// System.out.println(id + "被重画了...");
	}

	// 方法：停止移动
	public void stopMove() {
		this.canMove = false;
	}

	// 方法：改变方向
	private void changeDirection() {

		int dice = (new Random()).nextInt(5);

		if (dice == 1) {
			this.direction = "右下";
		} else if (dice == 2) {
			this.direction = "左下";
		} else if (dice == 3) {
			this.direction = "左上";
		} else if (dice == 4) {
			this.direction = "右上";
		} else {
			this.direction = "右下";
		}

		System.out.println(id + "改变方向了...");
	}

	@Override
	public void mouseClicked(MouseEvent event) {
		changeDirection();
	}

	@Override
	public void mouseEntered(MouseEvent event) {
		changeDirection();
	}

	@Override
	public void mouseExited(MouseEvent event) {
		changeDirection();
	}

	@Override
	public void mousePressed(MouseEvent event) {
		changeDirection();
	}

	@Override
	public void mouseReleased(MouseEvent event) {
		changeDirection();
	}
}