How to capture a JFrame's close button click event?

问题

I want to call a method confirmExit() when the red close button of the title bar of a JFrame is clicked.

How can I capture that event?

I'd also like to prevent the window from closing if the user chooses not to proceed.

回答1:

import javax.swing.JOptionPane;
import javax.swing.JFrame;

/*Some piece of code*/
frame.addWindowListener(new java.awt.event.WindowAdapter() {
    @Override
    public void windowClosing(java.awt.event.WindowEvent windowEvent) {
        if (JOptionPane.showConfirmDialog(frame, 
            "Are you sure you want to close this window?", "Close Window?", 
            JOptionPane.YES_NO_OPTION,
            JOptionPane.QUESTION_MESSAGE) == JOptionPane.YES_OPTION){
            System.exit(0);
        }
    }
});

If you also want to prevent the window from closing unless the user chooses 'Yes', you can add:

frame.setDefaultCloseOperation(JFrame.DO_NOTHING_ON_CLOSE);

回答2:

Override windowClosing Method.

public void windowClosing(WindowEvent e)

It is invoked when a window is in the process of being closed. The close operation can be overridden at this point.

回答3:

    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

also works. First create a JFrame called frame, then add this code underneath.

回答4:

This may work:

jdialog.addWindowListener(new WindowAdapter() {
    public void windowClosed(WindowEvent e) {
        System.out.println("jdialog window closed event received");
    }

    public void windowClosing(WindowEvent e) {
        System.out.println("jdialog window closing event received");
    }
});

Source: https://alvinalexander.com/java/jdialog-close-closing-event

回答5:

This is what I put as a menu option where I made a button on a JFrame to display another JFrame. I wanted only the new frame to be visible, and not to destroy the one behind it. I initially hid the first JFrame, while the new one became visible. Upon closing of the new JFrame, I disposed of it followed by an action of making the old one visible again.

Note: The following code expands off of Ravinda's answer and ng is a JButton:

ng.addActionListener((ActionEvent e) -> {
    setVisible(false);
    JFrame j = new JFrame("NAME");
    j.setVisible(true);
    j.addWindowListener(new java.awt.event.WindowAdapter() {
        @Override
        public void windowClosing(java.awt.event.WindowEvent windowEvent) {
            setVisible(true);
        }
    });
});

回答6:

Try this:

setDefaultCloseOperation(DO_NOTHING_ON_CLOSE);

It will work.

来源：https://stackoverflow.com/questions/9093448/how-to-capture-a-jframes-close-button-click-event

标签

java

swing

jframe

windowlistener