Java jFrame close button

Question

Hi i have a jFrame and I wish to ask the user whether he is sure to close the jframe when the close button is clicked:

    this.addWindowListener(new java.awt.event.WindowAdapter() {
    @Override
    public void windowClosing(java.awt.event.WindowEvent windowEvent) {
    Main ma = new Main();

    Object[] options = {"Yes", "NO"};

    int selectedOption = JOptionPane.showOptionDialog(ma, "Are you sure you want to close the system?", "Warning",
    JOptionPane.DEFAULT_OPTION, JOptionPane.WARNING_MESSAGE,
    null, options, options[0]);

           if (selectedOption == JOptionPane.YES_OPTION) {
               System.exit(0);
           }

    else
    {
    }

    }
    });

How shall i undo the close operation when he selects the 'NO' button from the jpanel popup?

possible duplicate of [Show prompt before closing JFrame](http://stackoverflow.com/questions/15449022/show-prompt-before-closing-jframe) — Mohsen Kamrani, Apr 20 '14 at 17:04
There is no need to have an else there. Only exits if yes-option selected else the application keeps running. — Costis Aivalis, Apr 20 '14 at 17:07

score 3 · Accepted Answer · answered Apr 20 '14 at 17:03

3

First you need to set the JFrame's default close action to do nothing on close:

myJFrame.setDefaultCloseOperation(JFrame.DO_NOTHING_ON_CLOSE);

Then pressing the close button will not close the JFrame, and you will have to dispose of it in code.

answered Apr 20 '14 at 17:03

Hovercraft Full Of Eels

283,665
25
256
373

score 1 · Answer 2 · answered Apr 20 '14 at 17:08

Set the default close operation to JFrame.DO_NOTHING, then use a WindowListener and listen for the windowClosing event. To close the frame now all you need to do is call dispose() on the frame. So:

public void windowClosing(WindowEvent e)  
{  
    JFrame frame = (JFrame)e.getWindow();  
    if (canClose(frame)) // you define canClose  
    {  
        frame.dispose();  
    }  
    else  
    {  
        // other stuff  
    }  
}

Java jFrame close button

2 Answers2