How to use JCheckBoxes selection for use?

Question

I have a checkbox on a JFrame. When I check it, I want to display on the command window that it has been selected. Below is the code i am working with. It compiles and executes without errors, but I don't get the "one has been selected" on the window when I select the checkbox.

 public Checklist() {

    ...

    JCheckBox one = new JCheckBox("CT scan performed");
    one.addItemListener(new CheckBoxListener());

    }
        private class CheckBoxListener implements ItemListener{
        public void itemStateChanged(ItemEvent e)
        {
        if(e.getSource()==one){ if(one.isSelected()){
        System.out.println("one has been selected");
            }
            else{System.out.println("nothing");}
            }
     }}

Answer 1

I have tested this simple example and it works perfectly (it writes "one has been selected" when you select the checkbox, and "nothing" when you deselect it):

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

public class Example extends JFrame{
    public JCheckBox one;

    public Example() {
        one = new JCheckBox("CT scan performed");
        one.addItemListener(new CheckBoxListener());
        setSize(300,300);
        getContentPane().add(one);
        setVisible(true);
    }

    private class CheckBoxListener implements ItemListener{
        public void itemStateChanged(ItemEvent e) {
            if(e.getSource()==one){
                if(one.isSelected()) {
                    System.out.println("one has been selected");
                } else {System.out.println("nothing");}
            }
        }
    }

    public static void main(String[] args) {
        new Example();
    }
}

In your example, it seems that one is declared in the constructor CheckList(). Are you sure that it can be accessed in the inner class CheckBoxListener?