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);
}
}