Java-我一次只能选中一个复选框吗？

Question

I have some code where it has 3 checkboxes and for some reason when I check one checkbox and then another the first one I check automatically unchecks... It was working before but then I changed some things around and it isnt't working anymore... Anyone know what is wrong with my code?

The code:

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

public class Pizza2 extends JFrame{
    public static void main(String[] args){
        new Pizza2();

    }
    JTextField name, phone, address;
    JRadioButton small, medium, large, thick, thin;
    JCheckBox pepperoni, ham, sausage;
    JButton okButton, closeButton;

    public Pizza2(){
        this.setTitle("Pizza Order");
        this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        this.setResizable(false);

        setIconImage(Toolkit.getDefaultToolkit().getImage(getClass().getResource("pizzaIcon.png")));
        ButtonListener bl = new ButtonListener();

        JPanel panel1 = new JPanel();
        panel1.setLayout(new GridBagLayout());

        addItem(panel1, new JLabel("Name:"), 0, 0, 1, 1, GridBagConstraints.EAST);
        addItem(panel1, new JLabel("Phone:"), 0, 1, 1, 1, GridBagConstraints.EAST);
        addItem(panel1, new JLabel("Address:"), 0, 2, 1, 1, GridBagConstraints.EAST);

        name = new JTextField(20);
        phone = new JTextField(10);
        address = new JTextField(20);

        addItem(panel1, name, 1, 0, 2, 1, GridBagConstraints.WEST);
        addItem(panel1, phone, 1, 1, 1, 1, GridBagConstraints.WEST);
        addItem(panel1, address, 1, 2, 2, 1, GridBagConstraints.WEST);

        Box sizeBox = Box.createVerticalBox();
        small = new JRadioButton("Small");
        medium = new JRadioButton("Medium");
        large = new JRadioButton("Large");
        small.setSelected(true);
        ButtonGroup sizeGroup = new ButtonGroup();
        sizeGroup.add(small);
        sizeGroup.add(medium);
        sizeGroup.add(large);
        sizeBox.add(small);
        sizeBox.add(medium);
        sizeBox.add(large);
        sizeBox.setBorder(BorderFactory.createTitledBorder("Size"));
        addItem(panel1, sizeBox, 0, 3, 1, 1, GridBagConstraints.NORTH);

        Box styleBox = Box.createVerticalBox();
        thin = new JRadioButton("Thin");
        thick = new JRadioButton("Thick");
        ButtonGroup styleGroup = new ButtonGroup();
        styleGroup.add(thin);
        styleGroup.add(thick);
        styleBox.add(thin);
        styleBox.add(thick);
        styleBox.setBorder(BorderFactory.createTitledBorder("Style"));
        addItem(panel1, styleBox, 1, 3, 1, 1, GridBagConstraints.NORTH);

        Box topBox = Box.createVerticalBox();
        pepperoni = new JCheckBox("Pepperoni");
        ham = new JCheckBox("Ham");
        sausage = new JCheckBox("Sausage");
        ButtonGroup topGroup = new ButtonGroup();
        topGroup.add(pepperoni);
        topGroup.add(ham);
        topGroup.add(sausage);
        topBox.add(pepperoni);
        topBox.add(ham);
        topBox.add(sausage);
        topBox.setBorder(BorderFactory.createTitledBorder("Toppings"));
        addItem(panel1, topBox, 2, 3, 1, 1, GridBagConstraints.NORTH);

        Box buttonBox = Box.createHorizontalBox();
        okButton = new JButton("OK");
        closeButton = new JButton("Close");
        okButton.addActionListener(bl);
        closeButton.addActionListener(bl);
        buttonBox.add(okButton);
        buttonBox.add(Box.createHorizontalStrut(20));
        buttonBox.add(closeButton);
        addItem(panel1, buttonBox, 2, 4, 1, 1, GridBagConstraints.NORTH);

        this.add(panel1);
        this.pack();
        this.setLocationRelativeTo(null);
        this.setVisible(true);
    }

    private void addItem(JPanel p, JComponent c, int x, int y, int width, int height, int align){
        GridBagConstraints gc = new GridBagConstraints();
        gc.gridx = x;
        gc.gridy = y;
        gc.gridwidth = width;
        gc.gridheight = height;
        gc.weightx = 100.0;
        gc.weighty = 100.0;
        gc.insets = new Insets(5, 5, 5, 5);
        gc.anchor = align;
        gc.fill = GridBagConstraints.NONE;
        p.add(c, gc);
    }

    private class ButtonListener implements ActionListener{
        boolean isValid = false;
        final String ENTRY = "This information is required";

        public void actionPerformed(ActionEvent e){

            if(e.getSource() == okButton){
                //CHECK IF FIELDS CONTAIN INFO
                if(name.getText().equals("") || name.getText().equals(ENTRY)){
                    isValid = false;
                    name.setText(ENTRY);
                }
                if(phone.getText().equals("") || phone.getText().equals(ENTRY)){
                    isValid = false;
                    phone.setText(ENTRY);
                }
                if(address.getText().equals("") || address.getText().equals(ENTRY)){
                    isValid = false;
                    address.setText(ENTRY);
                }
                else
                {
                    isValid = true;

                    //IF THE INFORMATION IS VALID:
                    if(isValid = true){
                        String tops = "";

                        if(pepperoni.isSelected()){
                            tops += "Pepperoni\n";
                        }
                        if(ham.isSelected()){
                            tops += "Ham\n";
                        }
                        if(sausage.isSelected()){
                            tops += "Sausage\n";
                        }

                        String msg = "You ordered a ";
                        if(small.isSelected()){
                            msg += "small pizza with ";
                        }
                        if(medium.isSelected()){
                            msg += "medium pizza with ";
                        }
                        if(large.isSelected()){
                            msg += "large pizza with ";
                        }

                        if(tops.equals("")){
                            msg += "no toppings.";
                        }
                        else{
                            msg += "the following toppings:\n" + tops;
                        }

                        String info = "\nDeliver to  " + name.getText() + " at " + address.getText();
                        String phoneNo = "\nYour phone number: " + phone.getText();
                        String fullMsg = msg + info + phoneNo;
                        JOptionPane.showMessageDialog(null, fullMsg, "Your Order", JOptionPane.INFORMATION_MESSAGE);
                        System.exit(0);
                    }
                }
            }
            else if(e.getSource() == closeButton){
                int message = JOptionPane.showConfirmDialog(null, "Your Order will be cancelled", "Cancel Order", JOptionPane.WARNING_MESSAGE);
                if(message == JOptionPane.OK_OPTION){
                    System.exit(0);
                }
            }
        }
    }
}

PLEASE FEEL FREE TO COPY THIS CODE INTO A COMPILER AND TRY TO FIND THE PROBLEM THANK YOU SO MUCH TO ANYONE WHO HELPS ME :D

Answer 1

It is the "pepperoni", "ham", and "sausage" checkboxes you are talking about? If you do not want this behaviour, do not put them in a ButtonGroup. That behaviour is what a ButtonGroup is for.

From the ButtonGroup documentation :

This class is used to create a multiple-exclusion scope for a set of buttons. Creating a set of buttons with the same ButtonGroup object means that turning "on" one of those buttons turns off all other buttons in the group.