JCheckBox does not deselect during runtime

Question

I've created a basic program that uses radio buttons, buttons and check boxes. My problem is that in runtime the check boxes can be selected but not deselected. I'm pretty sure its something simple but I've tried snippets of codes from oracle's website and it didn't seem to work. Could any point me to the right direction? Thanks.

This is an inner class that handles the events for the check boxes. It's suppose to receive the event and set the variables to the appropriate prices. I've tried elsebut that doesn't seem to work.

private void buildPanel()
{
    //Create the label, radio buttons, check boxes, and buttons
    messageLabel = new JLabel("Select the package of your choice: ");
    min1 = new JRadioButton("300 Minutes - $45.00 per month.");
    min2 = new JRadioButton("800 Minutes - $65.00 per month.");
    min3 = new JRadioButton("1500 Minutes -  $99.00 per month.");

    model1 = new JRadioButton("Model 100 - $29.95");
    model2 = new JRadioButton("Model 110 - $49.95 ");
    model3 = new JRadioButton("Model 200 - $99.95");

    vMail = new JCheckBox("Voice Mail  - $5.00 per month.");
    vMail.setSelected(false);
    textMes = new JCheckBox("Text Messaging - $10.00 per month.");
    textMes.setSelected(false);

    okButton = new Button("OK");

    //Group the radio buttons
    radiogroupmin = new ButtonGroup();
    radiogroupmin.add(min1);
    radiogroupmin.add(min2);
    radiogroupmin.add(min3);

    radiogroupmodel = new ButtonGroup();
    radiogroupmodel.add(model1);
    radiogroupmodel.add(model2);
    radiogroupmodel.add(model3);

    //Group the check boxes
    checkboxgroup = new ButtonGroup();

    checkboxgroup.add(vMail);
    checkboxgroup.add(textMes);

    //Add action listener to the radio buttons
    min1.addActionListener(new RadioButtonListener());
    min2.addActionListener(new RadioButtonListener());
    min3.addActionListener(new RadioButtonListener());

    model1.addActionListener(new RadioButtonListener());
    model2.addActionListener(new RadioButtonListener());
    model3.addActionListener(new RadioButtonListener());

    //Add action listener to the check boxes
    vMail.addItemListener(new CheckBoxListener());
    textMes.addItemListener(new CheckBoxListener());

    //Add action listener to the button
    okButton.addActionListener(new ButtonListener());

    //create a panel and add the components to it
    panel = new JPanel(new BorderLayout());
    panel.setLayout(new BoxLayout(panel, BoxLayout.PAGE_AXIS));

    panel.setBorder(BorderFactory.createEmptyBorder(5,5,5,5));
    panel.add(messageLabel);
    panel.add(min1);
    panel.add(min2);
    panel.add(min3);


    panel.add(model1);
    panel.add(model2);
    panel.add(model3);


    panel.add(vMail);
    panel.add(textMes);     

    panel.add(okButton);
}

public static class RadioButtonListener implements ActionListener
{       
        public static double minPrice;
        public static String model;
        public static double modelPrice = 0.0;

    public void actionPerformed(ActionEvent e)
    {
        if (e.getSource() == min1)
        {
            minPrice = 45.00;
        }
        else if(e.getSource() == min2)
        {
            minPrice = 65.00;
        }
        else if(e.getSource() == min3)
        {
            minPrice = 99.00;
        }

        if(e.getSource() == model1)
        {
            model = "Model 100";
            modelPrice = 29.00;
        }
        else if(e.getSource() == model2)
        {
            model = "Model 110";
            modelPrice = 49.99;
        }
        else if(e.getSource() == model3)
        {
            model = "Model 200";
            modelPrice = 99.99;
        }
    }


    public static double getMinPrice()
    {
        return minPrice;
    }

    public static  String getModel()
    {
        return model;
    }

    public static double getModelPrice()
    {
        return modelPrice;
    }
}

public static class CheckBoxListener implements ItemListener
{

    static double voicePrice;
    static double  textPrice;
    public void itemStateChanged(ItemEvent e) 
    {
        if(e.getSource() == vMail)
        {
            if (e.getStateChange() == ItemEvent.SELECTED)
            {
            voicePrice = 5.00;
            }
            else
            {
            voicePrice = 0.0;
            }
        }           

        if(e.getSource() == textMes)
        {
            if(e.getStateChange() == ItemEvent.SELECTED)
            {
                textPrice = 10.00;
            }
            else
            {
                textPrice = 0.0;
            }
        }
    }

    public static double getVoicePrice()
    {
        return voicePrice;
    }

    public static double getTextPrice()
    {
        return textPrice;
    }   

}
private  class ButtonListener implements ActionListener
{
    public void actionPerformed(ActionEvent e)
    {
        if(e.getSource() == okButton)
        {
            DecimalFormat df = new DecimalFormat("$00.##");

            double total;
            final double tax = 0.6;
            final double modelTax = (RadioButtonListener.getModelPrice() * tax) + RadioButtonListener.getModelPrice();
            total = RadioButtonListener.getMinPrice() + 
                    modelTax + CheckBoxListener.getVoicePrice() + CheckBoxListener.getTextPrice(); 
            JOptionPane.showMessageDialog(null, "Your total is: " + df.format(total));

        }
    }
}

Answer 1

Perhaps try changing both:

if(vMail.isSelected())

and:

if(textMes.isSelected())

to:

if(e.getStateChange() == ItemEvent.SELECTED)

Revised answer below based on the new info

Okay, there are a few problems:

1. Remove all code related to the checkboxgroup. You do not want to use a ButtonGroup from checkboxes! This is your main problem. The ButtonGroup is only generally used for JRadioButtons
2. Only create the one instance of CheckBoxListener, ie:

    // Add action listener to the check boxes
    CheckBoxListener checkBoxListener = new CheckBoxListener();
    vMail.addItemListener(checkBoxListener);
    textMes.addItemListener(checkBoxListener);