Help closing a gui

Question

Need some help
I want to pop up a gui made in JOptionPane when I close the editor gui. Basically I want to ask the user to confirm the closing because the file has not been saved.
I wrote the code but it is not working (you can find the code in question in the InnerDestroyer class)
What am I missing??
import javax.swing.JScrollPane;
import javax.swing.JFileChooser;
import javax.swing.JFrame;
import javax.swing.JTextArea;
import javax.swing.JTextField;
import javax.swing.JButton;
import javax.swing.JMenu;
import javax.swing.JMenuBar;
import javax.swing.JMenuItem;
import javax.swing.JPanel;
import javax.swing.JOptionPane;
import javax.swing.JLabel;
import java.awt.Container;
import java.awt.BorderLayout;
import java.awt.FlowLayout;
import java.awt.Color;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.WindowEvent;
import java.awt.event.WindowAdapter;
import java.io.File;
import java.io.FileWriter;
import java.io.FileReader;
import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.IOException;
import java.io.FileNotFoundException;
import java.util.logging.*;
* MyEditor class
public class MyEditor extends JFrame implements ActionListener
     public static final int WIDTH=600;
     public static final int HEIGHT = 620;
     public static final int LINES = 30;
     public static final int CHAR_PER_LINE = 53;
     private JTextArea theText;
      * Constructror,  creating the Text Editor GUI
     public MyEditor()
          setSize(WIDTH,HEIGHT);
          setTitle("My Editor");
          Container contentPane = getContentPane();
          contentPane.setLayout(new BorderLayout());
          JPanel buttonPanel = new JPanel();
          buttonPanel.setBackground(Color.white);
          buttonPanel.setLayout(new FlowLayout());
          JButton loadUrl = new JButton("Load URL");
          loadUrl.addActionListener(this);
          buttonPanel.add(loadUrl);
          JButton loadButton = new JButton("Load");
          loadButton.addActionListener(this);
          buttonPanel.add(loadButton);
          JButton saveButton = new JButton("Save");
          saveButton.addActionListener(this);
          buttonPanel.add(saveButton);
          contentPane.add(buttonPanel, BorderLayout.SOUTH);
          JPanel textPanel = new JPanel();
          textPanel.setBackground(Color.black);
          theText = new JTextArea(LINES, CHAR_PER_LINE);
          theText.setBackground(Color.white);
          textPanel.add(theText);
          contentPane.add(textPanel, BorderLayout.NORTH);
          JTextField textField = new JTextField(20);
          contentPane.add(textField, BorderLayout.CENTER);
          JScrollPane scrolledText = new JScrollPane(theText);
          textPanel.add(scrolledText);
          contentPane.add(textPanel, BorderLayout.NORTH);
          JMenu menu = new JMenu("File");
          JMenuItem m;
          m= new JMenuItem("Clear Text");
          m.addActionListener(this);
          menu.add(m);
          m= new JMenuItem("Exit Editor");
          m.addActionListener(this);
          menu.add(m);
          JMenuBar mBar = new JMenuBar();
          mBar.add(menu);
          setJMenuBar(mBar);
     public void actionPerformed(ActionEvent e)
          String actionCommand = e.getActionCommand();
          if (actionCommand.equals("Load"))
               try
                    JFileChooser chooser = new JFileChooser();
                    int returnVal = chooser.showOpenDialog(this);
                    if(returnVal == JFileChooser.APPROVE_OPTION)
                         FileReader freader = new FileReader(chooser.getSelectedFile());
                         BufferedReader breader = new BufferedReader (freader);
                         theText.setText("");
                         String line;
                         while ((line= breader.readLine()) !=null)
                              theText.append(line + "\n");
                         breader.close();
               catch(FileNotFoundException g)
                    String error1= "Error opening the file ";
                    String error2 = "or the file was not found";
                    theText.setText(error1 +" " + error2);
               catch(IOException g)
                    theText.setText("Error rerading from file");
          if (actionCommand.equals("Load URL"))
               try
                    JFileChooser chooser = new JFileChooser();
                    int returnVal = chooser.showOpenDialog(this);
                    if(returnVal == JFileChooser.APPROVE_OPTION)
                         FileReader freader = new FileReader(chooser.getSelectedFile());
                         BufferedReader breader = new BufferedReader (freader);
                         theText.setText("");
                         String line;
                         while ((line= breader.readLine()) !=null)
                              theText.append(line + "\n");
                              breader.close();
                    catch(FileNotFoundException g)
                         String error1= "Error opening the file ";
                         String error2 = "or the file was not found";
                         theText.setText(error1 +" " + error2);
                    catch(IOException g)
                         theText.setText("Error rerading from file");
          else if  (actionCommand.equals("Save"))
               try
                    JFileChooser chooser = new JFileChooser();
                    ExampleFileFilter filter = new ExampleFileFilter();
                     filter.addExtension("txt");
                        filter.addExtension("html");
                        filter.setDescription("txt & html files");
                        chooser.setFileFilter(filter);
                    int returnVal = chooser.showSaveDialog(this);
                    if(returnVal == JFileChooser.APPROVE_OPTION)
                         FileWriter fwriter = new FileWriter(chooser.getSelectedFile());
                         BufferedWriter bwriter = new BufferedWriter (fwriter);
                         bwriter.write(theText.getText());
                         bwriter.close();
               catch(IOException io)
                    theText.setText("Error saving!");
          else if(actionCommand.equals("Exit Editor"))
               System.exit(1);
          else if(actionCommand.equals("Clear Text"))
               theText.setText("");
          else
               theText.setText("Error in editor interface");
public class InnerDestroyer extends WindowAdapter
     public void windowClosing(WindowEvent e)
          JOptionPane op =new JOptionPane();
          JLabel  jl = new JLabel("Document has not been saved");
          op.showMessageDialog( null, jl, "Warning!", JOptionPane.QUESTION_MESSAGE);
          op.setVisible(true);
      *//*Main class, making the editor Gui visible**/
     public static void main(String[] args)
          MyEditor guiEditor = new MyEditor();
            guiEditor.setVisible(true);
}

Answer 1

import java.awt.*;
import javax.swing.*;
import java.awt.event.*;
public class Test extends JFrame {
  JCheckBox jcb = new JCheckBox("Check Me, Check Me!!!!");
  public Test() {
    Container content = getContentPane();
    content.setLayout(new FlowLayout());
    content.add(jcb);
    this.setDefaultCloseOperation(JFrame.DO_NOTHING_ON_CLOSE);
    addWindowListener(new WindowAdapter() {
      public void windowClosing(WindowEvent we) {
     if (jcb.isSelected()) System.exit(0);
     else if (JOptionPane.showConfirmDialog(null,
           "You forgot to check the box!\nAre you sure you want to exit",
           "DUMB",JOptionPane.OK_CANCEL_OPTION, JOptionPane.WARNING_MESSAGE)==
          JOptionPane.OK_OPTION) System.exit(0);
    setSize(200, 200);
    setVisible(true);
  public static void main(String[] args){
    new Test();
}If you have a question about this, look at it again. If you still have a question, search the forums.