Java学习笔记--多线程

rollenholt的博文：http://www.cnblogs.com/rollenholt/archive/2011/08/28/2156357.html

弹球例子：

0. 创建Bounce框架 JFrame frame = new BounceFrame();
    BounceFrame自定义了addButton、addBall方法，用于在frame内的panel添加按钮、小球

1. 设置标题 setTitle("bounce");
2. 创建BallComponent comp = new Ballcomponent();
　 BallComponent继承于JPanel。专门用于容纳并绘制Ball
3. 将comp添加到框架frame

4. 创建JPanel buttonPanel = new JPanel();用于存放start、close按钮
5. 创建start、close按钮，并添加到buttonPanel中
6. 将buttonPanel添加到框架frame

代码：

Bounce.java　

public class Bounce {
	public static void main(String args[]){
		EventQueue.invokeLater(new Runnable(){
			public void run(){
				JFrame frame = new BounceFrame();
				frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
				frame.setVisible(true);
			}
		});
	}
}

class BallRunnable implements Runnable{
	private Ball ball;
	private Component component;
	public static final int STEPS =2000;
	public static final int DELAY = 5 ;
	
	public BallRunnable(Ball ball , Component component){
		this.ball=ball;
		this.component = component;
	}
	
	public void run(){
		try {
			for(int i = 0 ; i < STEPS ; i++){
				ball.move(component.getBounds());	//移动小球
				//repaint会激活component的paintComponent方法
				component.repaint();
				Thread.sleep(DELAY);
			}
		}catch(InterruptedException e){
			//处理异常
		}
	}
}

class BounceFrame extends JFrame{
	private BallComponent comp;
		
	public BounceFrame(){
		setTitle("Bounce");
		comp = new BallComponent();
		add(comp,BorderLayout.CENTER);
		JPanel buttonPanel = new JPanel();
		addButton(buttonPanel,"Start",new ActionListener(){
			public void actionPerformed(ActionEvent e){
				addBall();
			}
		});
			
		addButton(buttonPanel , "Close" , new ActionListener(){
			public void actionPerformed(ActionEvent e){
				System.exit(0);
			}
		});
		add(buttonPanel,BorderLayout.SOUTH);
		pack();
	}
	
	public void addButton(Container c, String title , ActionListener listener){
		JButton button = new JButton(title);
		c.add(button);
		button.addActionListener(listener);
	}
	
	public void  addBall(){
		try{
			Ball ball = new Ball();
			comp.add(ball);
			Runnable r = new BallRunnable(ball,comp);
			Thread t = new Thread(r);
			t.start();
			
		}catch(Exception e){
			//处理异常
		}
	}
	
}

　　

Ball.java

package com.thread.Multithreadball;

import java.awt.geom.Ellipse2D;
import java.awt.geom.Rectangle2D;

public class Ball {
	private static final int XSIZE = 15;
	private static final int YSIZE = 15;
	private double  x = 0;
	private double  y = 0;
	private double  dx = 1;
	private double  dy = 1;
	
	
	public void move(Rectangle2D bounds){
		x += dx;
		y += dy;
		if(x<bounds.getMinX()){
			x=bounds.getMinX();
			dx=-dx;
		}
		
		if(x + XSIZE >= bounds.getMaxX()){
			x=bounds.getMaxX()-XSIZE;
			dx=-dx;
		}
		
		if(y<bounds.getMinY()){
			y=bounds.getMinY();
			dy=-dy;
		}
		
		if(y + YSIZE >= bounds.getMaxY()){
			y = bounds.getMaxY() - YSIZE;
			dy=-dy;
		}
	}
	
	//获取当前的小球
	public Ellipse2D getShape(){
		return new Ellipse2D.Double(x,y,XSIZE,YSIZE);
	}
}

BallComponent.java

public class BallComponent extends JPanel{
	private static final int DEFAULT_WIDTH = 450;
	private static final int DEFAULT_HEIGHT = 350;
	
	private List<Ball> balls = new ArrayList<>();
	
	//将一个球加入到component
	public void add(Ball b ){
		balls.add(b);
	}
	
	public void paintComponent (Graphics g){
		super.paintComponent(g);
		Graphics2D g2 = (Graphics2D) g;
		for(Ball b : balls){
			g2.fill(b.getShape());
		}
	}
	
	public Dimension getPreferredSize(){
		return new Dimension(DEFAULT_WIDTH,DEFAULT_HEIGHT);
	}
}