/* * Copyright (c) 1995, 2008, Oracle and/or its affiliates. All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * * - Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * * - Redistributions 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 Oracle or the names of its * contributors may be used to endorse or promote products derived * from this software without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS * IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. */ package events; /* * ComponentEventDemo.java requires no other files. */ import javax.swing.*; import java.awt.*; import java.awt.event.*; 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(e.getComponent().getClass().getName() + " --- Hidden"); } public void componentMoved(ComponentEvent e) { displayMessage(e.getComponent().getClass().getName() + " --- Moved"); } public void componentResized(ComponentEvent e) { displayMessage(e.getComponent().getClass().getName() + " --- Resized "); } public void componentShown(ComponentEvent e) { displayMessage(e.getComponent().getClass().getName() + " --- Shown"); } /** * Create the GUI and show it. For thread safety, * this method should be invoked from the * event-dispatching thread. */ private static void createAndShowGUI() { //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(); } }); } }