[adlb1300]

I have a program that will create a new ball each time you click the add ball button adds a randomly colored ball to the window. Problem is I know want to create a button that will delete a ball when it is clicked. I have tried a number of things but to no avail. Below is the code I have and I was hoping someone could look it over and see if they can find what I'm missing.

Thanks

Code:

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

public class BounceBall{
    
    public static void main(String[] args) {
        
        JFrame frame = new BounceFrame();
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.setLocation(300,300);
        frame.setVisible(true);
    }
}

Code:

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


class BounceFrame extends JFrame {

    private BallCanvas canvas;
    public static final int WIDTH = 450;
    public static final int HEIGHT = 350;

    
    public BounceFrame() {
        setSize(WIDTH, HEIGHT);
        setTitle("BounceThread");
        
        Container contentPane = getContentPane();
        canvas = new BallCanvas();
        contentPane.add(canvas, BorderLayout.CENTER);
        JPanel buttonPanel = new JPanel();
        addButton(buttonPanel, "Add Ball",
                new ActionListener() {
            public void actionPerformed(ActionEvent evt) {
                addBall();
            }
        });
        
        addButton(buttonPanel, "Delete Ball",
                new ActionListener() {
            public void actionPerformed(ActionEvent evt) {
                      delBall();
                }
        });
        
        addButton(buttonPanel, "Exit",
                new ActionListener() {
            public void actionPerformed(ActionEvent evt) {
                System.exit(0);
            }
        });
        contentPane.add(buttonPanel, BorderLayout.SOUTH);
    }
    
    public void addButton(Container c, String title,
            ActionListener listener) {
        JButton button = new JButton(title);
        c.add(button);
        button.addActionListener(listener);
    }
    
    public void addBall() {
        BouncingBall b = new BouncingBall(canvas);
        canvas.add(b);
        BallThread thread = new BallThread(b);
        thread.start();
    }
    
    public void delBall(){
        BouncingBall db = new BouncingBall(canvas);
        canvas.delBall(db);
    }
}

Code:

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

class BallCanvas extends JPanel {

    private ArrayList<BouncingBall> balls = new ArrayList<BouncingBall>();
    
    public void add(BouncingBall b) {
        balls.add(b);
    }
    
    public void paintComponent(Graphics g) {
        super.paintComponent(g);
        Graphics2D g2 = (Graphics2D)g;
        for (int i = 0; i < balls.size(); i++) {
            BouncingBall b = (BouncingBall)balls.get(i);
            b.draw(g2);
        }
    }

    public void delBall(BouncingBall db) {
        balls.remove(db);
    }
    
}

Code:

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

class BouncingBall {
    
    private Component canvas;
    private static final int XSIZE = 15;
    private static final int YSIZE = 15;
    private int x = 0; 
    private int y = 0; 
    private int dx;
    private int dy;
    Color color;
    
    public BouncingBall(Component c) {
        canvas = c;
        color = getColor();
        dx = getSpeed();
        dy = getSpeed();
    }
    
    public void draw(Graphics2D g2) {
    
        g2.setColor(color); 
        g2.fillOval(x,y,15,15);   // adds color to circle
        g2.drawOval(x,y,15,15);   // draws circle
        
    }
    
    public void move() {
        x += dx;
        y += dy;
        if (x < 0) {
            x = 0;
            dx = -dx;
        }
        if (x + XSIZE >= canvas.getWidth()) {
            x = canvas.getWidth() - XSIZE;
            dx = -dx;
        }
        if (y < 0) {
            y = 0;
            dy = -dy;
        }
        if (y + YSIZE >= canvas.getHeight()) {
            y = canvas.getHeight() - YSIZE;
            dy = -dy;
        }
        
        canvas.repaint();
    }
    
    private Color getColor() {
        int rval = (int)Math.floor(Math.random() * 256);
        int gval = (int)Math.floor(Math.random() * 256);
        int bval = (int)Math.floor(Math.random() * 256);
        return new Color(rval, gval, bval);
   }
    
    private int getSpeed() {
        return 10 + (int)Math.floor(Math.random() * 4);
    }
}

Code:

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

class BallThread extends Thread {
    
    private BouncingBall b;
    boolean keepBouncing = true;
    
    public BallThread(BouncingBall aBall) { 
        b = aBall; 
    }
    
    public void run() {
        try {
            while(keepBouncing){
//            for (int i = 1; i <= 1000; i++) {
                b.move();
                sleep(50);
            }
        } catch (InterruptedException exception) {
            keepBouncing = false;
        }
    }
    
}