Associate predefined action to close button Java J

问题:

I have an action defined in the same package as the JDialog. I want to bind the Java Dialog`s close button to this action, without using window listeners. Just set once this action to the button. Can you help me do this, please? Thank you

回答1:

The following code should achieve what you need using a WindowAdapter as a WindowListener. The windowClosing method is called exactly once upon pressing the close button. If you plan to add an alternative Close-Button you can always fire a windowClosing event and do not need to handle it separatly.

import java.awt.EventQueue;
import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;
import javax.swing.JDialog;
import javax.swing.WindowConstants;
public class DummyDialog extends JDialog {

DummyDialog() {
    this.setDefaultCloseOperation(WindowConstants.DISPOSE_ON_CLOSE);
    this.addWindowListener(new WindowAdapter() {

        @Override
        public void windowClosing(WindowEvent arg0) {
             System.out.println("Window closing");
        }



    });

}

public static void main(String[] args) {
    EventQueue.invokeLater(new Runnable() {
        public void run() {
            try {
                DummyDialog d = new DummyDialog();
              d.setVisible(true);
            } catch (Exception e) {
                e.printStackTrace();
            }
        }
    });
}

}

回答2:

By default Swing will use the widgets of the OS you are running on so you don't have access to the button since it is not a Swing component.

If you want to use the Swing LAF then you can access the close button and add your ActionListener to the button. The code would be:

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

public class DialogCloseAction
{
    private static void createAndShowGUI()
    {
        JDialog.setDefaultLookAndFeelDecorated(true);
        JDialog dialog = new JDialog();
        dialog.setDefaultCloseOperation( JDialog.DISPOSE_ON_CLOSE );
        dialog.setSize(200, 200);
        dialog.setLocationRelativeTo(null);
        dialog.setVisible( true );

        Action close = new AbstractAction()
        {
            public void actionPerformed(ActionEvent e)
            {
                System.out.println("closing...");
            }
        };

        JButton button = SwingUtils.getDescendantOfType(
            JButton.class, dialog.getRootPane(), "Icon", UIManager.getIcon("InternalFrame.closeIcon"));
        button.addActionListener( close );
    }

    public static void main(String[] args)
    {
        EventQueue.invokeLater(new Runnable()
        {
            public void run()
            {
                createAndShowGUI();
            }
        });
    }
}

You will need to use Darryl's Swing Utils class to search the frame for the custom button.

Otherwise, as has already been suggested, you will need to use a WindowListener. If you want you can check out Closing an Application which has a simple API that allows you to add an Action to the custom CloseListener.