Java实力弹弹球实现代码

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("弹弹球");
    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);//默认是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]);
    }
    //让当前画布监听 焦点事件
    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);
      //让每个球的坐标变化一下---（x坐标）
      balls[i].x = balls[i].left ? balls[i].x-10:balls[i].x+10;
      //当球碰壁时，更改球的方向
      if(balls[i].x<=0||balls[i].x>=this.getWidth()-24){
        balls[i].left = !balls[i].left;//切换方向
      }
      //让每个球的坐标变化一下---（y坐标）
      balls[i].y = balls[i].up ? balls[i].y-10:balls[i].y+10;
      //当球碰壁时，更改球的方向
      if(balls[i].y<=0||balls[i].y>=this.getHeight()-22){
        balls[i].up = !balls[i].up;//切换方向
      }
      g.fillOval(balls[i].x, balls[i].y, 20, 20);
    }
  }
  @Override
  public void actionPerformed(ActionEvent e) {
    //System.out.println("aaa");
    repaint();//刷新画布.调用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;
    }
  }
}