先看看效果圖：
直接上代碼了。
微調按鈕加畫布畫幾個圓，再實現監聽。 。 。
package cn.hncu.threadDemo.thread2;import java.awt.Canvas;import java.awt.Color;import java.awt.Graphics;import java.awt.event.ActionEvent;import java.awt.event.ActionListener;import java.awt.event.FocusEvent;import java.awt.event.FocusListener;import javax.swing.JFrame;import javax.swing.JLabel;import javax.swing.JPanel;import javax.swing.JSpinner;import javax.swing.Timer;import javax.swing.event.ChangeEvent;import javax.swing.event.ChangeListener;public class BallsJFrame extends JFrame implements ChangeListener{ private BallsCanvas ball; private JSpinner spinner; public BallsJFrame(){ super("彈彈球"); this.setBounds(300, 200, 400, 300); this.setDefaultCloseOperation(EXIT_ON_CLOSE); Color colors[] = {Color.red,Color.green,Color.blue,Color.magenta,Color.cyan}; ball = new BallsCanvas(colors,100); this.getContentPane().add(ball);//默認是CENTER位置JPanel panel = new JPanel(); this.getContentPane().add(panel,"South"); panel.add(new JLabel("Delay")); spinner = new JSpinner(); spinner.setValue(100); panel.add(spinner); spinner.addChangeListener(this); this.setVisible(true); } @Override public void stateChanged(ChangeEvent e) { int value = Integer.parseInt(""+spinner.getValue()); ball.setDelay(value); } public static void main(String[] args) { new BallsJFrame(); }}class BallsCanvas extends Canvas implements ActionListener, FocusListener{ private Ball balls[];//存放所有的球private Timer timer;//javax.swing.Timer public BallsCanvas(Color colors[] ,int delay){ this.balls = new Ball[colors.length]; for(int i=0,x=40;i<colors.length;i++,x+=20){ this.balls[i] = new Ball(x,x,colors[i]); } //讓當前畫布監聽焦點事件this.addFocusListener(this); timer = new Timer(delay,this); timer.start(); } public void setDelay(int delay){ timer.setDelay(delay); } @Override public void paint(Graphics g) { for(int i=0;i<this.balls.length;i++){ g.setColor(balls[i].color); //讓每個球的坐標變化一下---（x坐標） balls[i].x = balls[i].left ? balls[i].x-10:balls[i].x+10; //當球碰壁時，更改球的方向if(balls[i].x<=0||balls[i].x>=this.getWidth()-24){ balls[i].left = !balls[i].left;//切換方向} //讓每個球的坐標變化一下---（y坐標） balls[i].y = balls[i].up ? balls[i].y-10:balls[i].y+10; //當球碰壁時，更改球的方向if(balls[i].y<=0||balls[i].y>=this.getHeight()-22){ balls[i].up = !balls[i].up;//切換方向} g.fillOval(balls[i].x, balls[i].y, 20, 20); } } @Override public void actionPerformed(ActionEvent e) { //System.out.println("aaa"); repaint();//刷新畫布.調用paint(Graphics g) } @Override public void focusGained(FocusEvent e) { timer.stop(); } @Override public void focusLost(FocusEvent e) { timer.restart(); } private static class Ball{ int x,y; boolean up,left; Color color; public Ball(int x, int y, Color color) { this.x = x; this.y = y; this.color = color; up = left = false; } }}以上就是本文的全部內容，希望對大家的學習有所幫助，也希望大家多多支持武林網。