ComponentEventDemo.java Source code

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Here is the source code for ComponentEventDemo.java

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/* From http://java.sun.com/docs/books/tutorial/index.html */
/*
 * Copyright (c) 2006 Sun Microsystems, Inc. All Rights Reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 * -Redistribution of source code must retain the above copyright notice, this
 *  list of conditions and the following disclaimer.
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 * -Redistribution in binary form must reproduce the above copyright notice,
 *  this list of conditions and the following disclaimer in the documentation
 *  and/or other materials provided with the distribution.
 *
 * Neither the name of Sun Microsystems, Inc. or the names of contributors may
 * be used to endorse or promote products derived from this software without
 * specific prior written permission.
 *
 * This software is provided "AS IS," without a warranty of any kind. ALL
 * EXPRESS OR IMPLIED CONDITIONS, REPRESENTATIONS AND WARRANTIES, INCLUDING
 * ANY IMPLIED WARRANTY OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE
 * OR NON-INFRINGEMENT, ARE HEREBY EXCLUDED. SUN MIDROSYSTEMS, INC. ("SUN")
 * AND ITS LICENSORS SHALL NOT BE LIABLE FOR ANY DAMAGES SUFFERED BY LICENSEE
 * AS A RESULT OF USING, MODIFYING OR DISTRIBUTING THIS SOFTWARE OR ITS
 * DERIVATIVES. IN NO EVENT WILL SUN OR ITS LICENSORS BE LIABLE FOR ANY LOST
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 *
 * You acknowledge that this software is not designed, licensed or intended
 * for use in the design, construction, operation or maintenance of any
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 */
/*
 * ComponentEventDemo.java is a 1.4 example that requires no other files.
 */

import java.awt.BorderLayout;
import java.awt.Component;
import java.awt.Dimension;
import java.awt.event.ComponentEvent;
import java.awt.event.ComponentListener;
import java.awt.event.ItemEvent;
import java.awt.event.ItemListener;

import javax.swing.JCheckBox;
import javax.swing.JComponent;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.JTextArea;

public class ComponentEventDemo extends JPanel implements ComponentListener, ItemListener {
    static JFrame frame;

    JTextArea display;

    JLabel label;

    String newline = "\n";

    public ComponentEventDemo() {
        super(new BorderLayout());

        display = new JTextArea();
        display.setEditable(false);
        JScrollPane scrollPane = new JScrollPane(display);
        scrollPane.setPreferredSize(new Dimension(350, 200));

        JPanel panel = new JPanel(new BorderLayout());
        label = new JLabel("This is a label", JLabel.CENTER);
        label.addComponentListener(this);
        panel.add(label, BorderLayout.CENTER);

        JCheckBox checkbox = new JCheckBox("Label visible", true);
        checkbox.addItemListener(this);
        checkbox.addComponentListener(this);
        panel.add(checkbox, BorderLayout.PAGE_END);
        panel.addComponentListener(this);

        add(scrollPane, BorderLayout.CENTER);
        add(panel, BorderLayout.PAGE_END);
        frame.addComponentListener(this);
    }

    public void itemStateChanged(ItemEvent e) {
        if (e.getStateChange() == ItemEvent.SELECTED) {
            label.setVisible(true);

            //Need to revalidate and repaint, or else the label
            //will probably be drawn in the wrong place.
            label.revalidate();
            label.repaint();
        } else {
            label.setVisible(false);
        }
    }

    protected void displayMessage(String message) {
        //If the text area is not yet realized, and
        //we tell it to draw text, it could cause
        //a text/AWT tree deadlock. Our solution is
        //to ensure that the text area is realized
        //before attempting to draw text.
        if (display.isShowing()) {
            display.append(message + newline);
            display.setCaretPosition(display.getDocument().getLength());
        }
    }

    public void componentHidden(ComponentEvent e) {
        displayMessage("componentHidden event from " + e.getComponent().getClass().getName());
    }

    public void componentMoved(ComponentEvent e) {
        Component c = e.getComponent();
        displayMessage("componentMoved event from " + c.getClass().getName() + "; new location: "
                + c.getLocation().x + ", " + c.getLocation().y);
    }

    public void componentResized(ComponentEvent e) {
        Component c = e.getComponent();
        displayMessage("componentResized event from " + c.getClass().getName() + "; new size: " + c.getSize().width
                + ", " + c.getSize().height);
    }

    public void componentShown(ComponentEvent e) {
        displayMessage("componentShown event from " + e.getComponent().getClass().getName());
    }

    /**
     * Create the GUI and show it. For thread safety, this method should be
     * invoked from the event-dispatching thread.
     */
    private static void createAndShowGUI() {
        //Make sure we have nice window decorations.
        JFrame.setDefaultLookAndFeelDecorated(true);

        //Create and set up the window.
        frame = new JFrame("ComponentEventDemo");
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

        //Create and set up the content pane.
        JComponent newContentPane = new ComponentEventDemo();
        newContentPane.setOpaque(true); //content panes must be opaque
        frame.setContentPane(newContentPane);

        //Display the window.
        frame.pack();
        frame.setVisible(true);
    }

    public static void main(String[] args) {
        //Schedule a job for the event-dispatching thread:
        //creating and showing this application's GUI.
        javax.swing.SwingUtilities.invokeLater(new Runnable() {
            public void run() {
                createAndShowGUI();
            }
        });
    }
}