如何在java中更改球图形的颜色和类型

/**一个可运行的程序为一个反弹的球设置动画*/

package bouncetugas;

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import java.awt.geom.*;
import java.awt.*;
import java.util.*;
import javax.swing.*;


public class BounceTugas {

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);
                }
            });
    }
}

/使用要显示的构件构造框架 弹跳球、开始和关闭按钮/

//将按钮添加到容器中

    public BounceFrame()
    {

    setSize(DEFAULT_WIDTH, DEFAULT_HEIGHT);
    setTitle("Bounce Latihan");

    comp = new BallComponent();
    add(comp, BorderLayout.CENTER);
    JPanel buttonPanel = new JPanel();
     addButton(buttonPanel, "Add Ball", new ActionListener()
    {

        public void actionPerformed(ActionEvent event)
        {
            addBall();
        }
    });

      addButton(buttonPanel, "Remove Ball", new ActionListener()
    {
        public void actionPerformed(ActionEvent event)
        {
            addBall();
        }
    });
       addButton(buttonPanel, "Change Color", new ActionListener()
    {
        public void actionPerformed(ActionEvent event)
        {
            addBall();
        }
    });
        addButton(buttonPanel, "Change Type", new ActionListener()
    {
        public void actionPerformed(ActionEvent event)
        {
            addBall();
        }
    });
          addButton(buttonPanel, "Start", new ActionListener()
    {
        public void actionPerformed(ActionEvent event)
        {
            addBall();
        }
    });
         addButton(buttonPanel, "Pause", new ActionListener()
    {
        public void actionPerformed(ActionEvent event)
        {
            pauseBall();
        }
    });
         addButton(buttonPanel, "Close", new ActionListener()
    {
        public void actionPerformed(ActionEvent event)
        {
            System.exit(0);
        }
    });

    add(buttonPanel, BorderLayout.SOUTH);
}

//将反弹球添加到画布并启动线程使其反弹

public void addButton(Container c, String title, ActionListener listener)
{

    JButton button = new JButton(title);
    c.add(button);
    button.addActionListener(listener);

}

//我不知道我应该写什么代码

public void addBall()
{
    Ball b = new Ball();
    comp.add(b);
    Runnable r = new BallRunnable(b, comp);
    Thread t = new Thread(r);
    t.start();
}

public void pauseBall()
{

//包装弹跳

}

private BallComponent comp;
public static final int DEFAULT_WIDTH = 650;
public static final int DEFAULT_HEIGHT = 450;
public static final int STEPS = 1000;
public static final int DELAY = 3;
}

//将球移动到下一个位置， //如果碰到其中一条边，则反转方向

class Ball {

//吸引球的部件

public Ellipse2D getShape()
{

return new Ellipse2D.Double(x,y, XSIZE, YSIZE);
}


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;
}

//将球添加到零部件

class BallComponent extends JPanel {

//抹去

public void add(Ball b)
{
   balls.add(b); 
}

public void paintComponent(Graphics g)
{

super.paintComponent（g）；
图形2d g2=（图形2d）g；
用于（球b：球）
{
g2.填充（b.getShape（））；
}
}
private ArrayList balls=new ArrayList（）；
}

很抱歉，我忘了对问题进行描述。我要说的是。。我无法使按钮包含更改颜色和形状的方法。请帮助我。试着发布一个而不是你的整个程序，并编辑你的帖子，让它问一个更具体的问题。推荐阅读：你知道你可以编辑你的问题吗？并将描述放在第一位，因为人们第一次看到你的问题时会看到它您可以调用

g2.setColor（Color.RED）

左右……对不起，只是初学者……下次更好。

public Ellipse2D getShape()
{

return new Ellipse2D.Double(x,y, XSIZE, YSIZE);
}


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;
}

class BallComponent extends JPanel {

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());

    }
}
 private ArrayList<Ball> balls = new ArrayList<Ball>();
}