How to override windowsClosing event in JFrame

Question

i'm developing a JFrame which has a button to show another JFrame. On the second JFrame i want to override WindowsClosing event to hide this frame but not close all the application. So i do like this:

On second JFrame

addWindowListener(new java.awt.event.WindowAdapter() {
    public void windowClosing(java.awt.event.WindowEvent evt) {
         formWindowClosing(evt);
    }
});

private void formWindowClosing(java.awt.event.WindowEvent evt) {
    this.dispose();
}

but application still close when i click x button on the windows. why? can you help me?

I can't use

setDefaultCloseOperation(DISPOSE_ON_CLOSE);

because i need to show again that JFrame with some information added in it during operations from first JFrame. So i init second JFrame with attribute visible false. if i use dispose i lose the information added in a second moment by the other JFrame. so i use

private void formWindowClosing(java.awt.event.WindowEvent evt) {
    this.setVisible(false);
}

but it still continue to terminate my entire app.

Answer 1

Adding a New Code with no WindowListener part as explained by @JBNizet, the very right thing. The default behaviour just hides the window, nothing is lost, you simply have to bring it back, every value inside it will remain as is, below is the sample program for further help :

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

public class TwoFrames
{
    private SecondFrame secondFrame;
    private int count = 0;

    private void createAndDisplayGUI()
    {
        JFrame frame = new JFrame("JFRAME 1");
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.setLocationByPlatform(true);

        secondFrame = new SecondFrame();
        secondFrame.createAndDisplayGUI();
        secondFrame.tfield.setText("I will be same everytime.");

        JPanel contentPane = new JPanel();  
        JButton showButton = new JButton("SHOW JFRAME 2");
        showButton.addActionListener(new ActionListener()
        {
            public void actionPerformed(ActionEvent ae)
            {
                secondFrame.tfield.setText(secondFrame.tfield.getText() + count);
                count++;
                if (!(secondFrame.isShowing()))
                    secondFrame.setVisible(true);
            }
        });

        frame.add(contentPane, BorderLayout.CENTER);
        frame.add(showButton, BorderLayout.PAGE_END);
        frame.setSize(200, 200);
        frame.setVisible(true);
    }

    public static void main(String... args)
    {
        SwingUtilities.invokeLater(new Runnable()
        {
            public void run()
            {
                new TwoFrames().createAndDisplayGUI();
            }
        });
    }
}

class SecondFrame extends JFrame
{
    private WindowAdapter windowAdapter;
    public JTextField tfield;

    public void createAndDisplayGUI()
    {
        setLocationByPlatform(true);

        JPanel contentPane = new JPanel();

         tfield = new JTextField(10);

        addWindowListener(windowAdapter);
        contentPane.add(tfield);

        getContentPane().add(contentPane);
        setSize(300, 300);      
    }
}

Is this what you want, try this code :

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

public class TwoFrames
{
    private SecondFrame secondFrame;

    private void createAndDisplayGUI()
    {
        JFrame frame = new JFrame("JFRAME 1");
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.setLocationByPlatform(true);

        secondFrame = new SecondFrame();
        secondFrame.createAndDisplayGUI();
        secondFrame.tfield.setText("I will be same everytime.");

        JPanel contentPane = new JPanel();  
        JButton showButton = new JButton("SHOW JFRAME 2");
        showButton.addActionListener(new ActionListener()
        {
            public void actionPerformed(ActionEvent ae)
            {
                if (!(secondFrame.isShowing()))
                    secondFrame.setVisible(true);
            }
        });

        frame.add(contentPane, BorderLayout.CENTER);
        frame.add(showButton, BorderLayout.PAGE_END);
        frame.setSize(200, 200);
        frame.setVisible(true);
    }

    public static void main(String... args)
    {
        SwingUtilities.invokeLater(new Runnable()
        {
            public void run()
            {
                new TwoFrames().createAndDisplayGUI();
            }
        });
    }
}

class SecondFrame extends JFrame
{
    private WindowAdapter windowAdapter;
    public JTextField tfield;

    public void createAndDisplayGUI()
    {
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        setLocationByPlatform(true);

        JPanel contentPane = new JPanel();

         tfield = new JTextField(10);

        windowAdapter = new WindowAdapter()
        {
            public void windowClosing(WindowEvent we)
            {
                setDefaultCloseOperation(JFrame.HIDE_ON_CLOSE);
            }
        };

        addWindowListener(windowAdapter);
        contentPane.add(tfield);

        getContentPane().add(contentPane);
        setSize(300, 300);      
    }
}