Stop execution of program until JDialog is exited

Question

I am trying to open up a bunch of JDialogs one after another. The goal is that only after one JDialog is closed the next one is created. I have tried to use setModal(true) for the dialogs, but somehow that does not make it work.

Just for you to get an idea, the code is roughly that:

for(Object o : mylist) {
    JDialog j = new JDialog();
    j.setModal(true);
}

The problem with that is that it opens up all the dialogs at once, so that multiple dialogs are open. How can I get what I want?

Answer 1

The following works for me. The below code displays a window containing a button with the text GO. When you click on the button, a JDialog appears with the title 0 (i.e. the digit zero) and a button with the text Close. When you click on the Close button, the JDialog disappears and another JDialog appears with the title 1 (i.e. the digit one) and a Close button. When you click on Close the JDialog disappears and another JDialog, with the title 2 appears.

import java.awt.EventQueue;
import java.awt.event.ActionEvent;

import javax.swing.JButton;
import javax.swing.JComponent;
import javax.swing.JDialog;
import javax.swing.JFrame;

public class GUI {
    private JFrame  frame;

    private void closeDialog(ActionEvent event) {
        ((JDialog) ((JComponent) event.getSource()).getTopLevelAncestor()).dispose();
    }

    private void createAndDisplayGui() {
        frame = new JFrame();
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        JButton button = new JButton("GO");
        button.addActionListener(this::showDialogs);
        frame.add(button);
        frame.pack();
        frame.setLocationByPlatform(true);
        frame.setVisible(true);
    }

    private void showDialogs(ActionEvent event) {
        for (int i = 0; i < 3; i++) {
            JDialog dlg = new JDialog(frame, true);
            dlg.setTitle(Integer.toString(i));
            JButton b = new JButton("Close");
            b.addActionListener(this::closeDialog);
            dlg.add(b);
            dlg.pack();
            dlg.setLocationRelativeTo(frame);
            dlg.setVisible(true);
        }
    }

    public static void main(String[] args) {
        EventQueue.invokeLater(() -> new GUI().createAndDisplayGui());
    }
}

• Method showDialogs is called when the GO button is clicked.
• Method showDialogs creates a modal JDialog.
• Calling method setVisible in the following line of code:

dlg.setVisible(true);

Method setVisible only returns after the modal JDialog has been closed.

• When the Close button (in the JDialog) is clicked, method closeDialog is called.
• Method closeDialog disposes the JDialog. Essentially the JDialog no longer exists after it has been disposed.
• Each loop iteration (in method showDialogs) is performed only after the JDialog it displays has been closed.