DialogTest.java Source code

Introduction

Here is the source code for DialogTest.java
Source

/*
   This program is a part of the companion code for Core Java 8th ed.
   (http://horstmann.com/corejava)
    
   This program is free software: you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation, either version 3 of the License, or
   (at your option) any later version.
    
   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.
    
   You should have received a copy of the GNU General Public License
   along with this program.  If not, see <http://www.gnu.org/licenses/>.
*/

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

import javax.swing.JButton;
import javax.swing.JDialog;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JMenu;
import javax.swing.JMenuBar;
import javax.swing.JMenuItem;
import javax.swing.JPanel;

/**
 * @version 1.33 2007-06-12
 * @author Cay Horstmann
 */
public class DialogTest {
    public static void main(String[] args) {
        EventQueue.invokeLater(new Runnable() {
            public void run() {
                DialogFrame frame = new DialogFrame();
                frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
                frame.setVisible(true);
            }
        });
    }
}

/**
 * A frame with a menu whose File->About action shows a dialog.
 */
class DialogFrame extends JFrame {
    public DialogFrame() {
        setTitle("DialogTest");
        setSize(DEFAULT_WIDTH, DEFAULT_HEIGHT);

        // construct a File menu

        JMenuBar menuBar = new JMenuBar();
        setJMenuBar(menuBar);
        JMenu fileMenu = new JMenu("File");
        menuBar.add(fileMenu);

        // add About and Exit menu items

        // The About item shows the About dialog

        JMenuItem aboutItem = new JMenuItem("About");
        aboutItem.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent event) {
                if (dialog == null) // first time
                    dialog = new AboutDialog(DialogFrame.this);
                dialog.setVisible(true); // pop up dialog
            }
        });
        fileMenu.add(aboutItem);

        // The Exit item exits the program

        JMenuItem exitItem = new JMenuItem("Exit");
        exitItem.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent event) {
                System.exit(0);
            }
        });
        fileMenu.add(exitItem);
    }

    public static final int DEFAULT_WIDTH = 300;
    public static final int DEFAULT_HEIGHT = 200;

    private AboutDialog dialog;
}

/**
 * A sample modal dialog that displays a message and waits for the user to click the Ok button.
 */
class AboutDialog extends JDialog {
    public AboutDialog(JFrame owner) {
        super(owner, "About DialogTest", true);

        // add HTML label to center

        add(new JLabel("<html><h1><i>Core Java</i></h1><hr>By Cay Horstmann and Gary Cornell</html>"),
                BorderLayout.CENTER);

        // Ok button closes the dialog

        JButton ok = new JButton("Ok");
        ok.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent event) {
                setVisible(false);
            }
        });

        // add Ok button to southern border

        JPanel panel = new JPanel();
        panel.add(ok);
        add(panel, BorderLayout.SOUTH);

        setSize(250, 150);
    }
}