一个JavaJECKBOX例子,带有 ItemEvent, ItemListener, setMnemonic, addItemListener, itemStateChanged

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/**
 * 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.
 *
 * -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
 * REVENUE, PROFIT OR DATA, OR FOR DIRECT, INDIRECT, SPECIAL, CONSEQUENTIAL,
 * INCIDENTAL OR PUNITIVE DAMAGES, HOWEVER CAUSED AND REGARDLESS OF THE THEORY
 * OF LIABILITY, ARISING OUT OF THE USE OF OR INABILITY TO USE THIS SOFTWARE,
 * EVEN IF SUN HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES.
 *
 * 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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 */
import java.awt.BorderLayout;
import java.awt.Font;
import java.awt.GridLayout;
import java.awt.event.ItemEvent;
import java.awt.event.ItemListener;
import java.awt.event.KeyEvent;
import javax.swing.BorderFactory;
import javax.swing.ImageIcon;
import javax.swing.JCheckBox;
import javax.swing.JComponent;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
/**
 * SwingCheckBoxDemo.java is a 1.4 application that requires 16 image files
 * in the images/geek directory: 
 * geek-----.gif, geek-c---.gif, geek--g--.gif, geek---h-.gif, geek----t.gif,
 * geek-cg--.gif, ..., geek-cght.gif.
 */
public class SwingCheckBoxDemo extends JPanel
 implements ItemListener {
 JCheckBox chinButton;
 JCheckBox glassesButton;
 JCheckBox hairButton;
 JCheckBox teethButton;
 /**
 * Four accessory choices provide for 16 different
 * combinations. The image for each combination is
 * contained in a separate image file whose name indicates
 * the accessories. The filenames are\"geek-XXXX.gif\"
 * where XXXX can be one of the following 16 choices.
 * The\"choices\" StringBuffer contains the string that
 * indicates the current selection and is used to generate
 * the file name of the image to display.
 ---- //zero accessories
 c--- //one accessory
 -g--
 --h-
 ---t
 cg-- //two accessories
 c-h-
 c--t
 -gh-
 -g-t
 --ht
 -ght //three accessories
 c-ht
 cg-t
 cgh-
 cght //all accessories
 */
 StringBuffer choices;
 JLabel pictureLabel;
 public SwingCheckBoxDemo() {
 super(new BorderLayout());
 //Create the check boxes.
 chinButton = new JCheckBox(\"Chin\");
 chinButton.setMnemonic(KeyEvent.VK_C);
 chinButton.setSelected(true);
 glassesButton = new JCheckBox(\"Glasses\");
 glassesButton.setMnemonic(KeyEvent.VK_G);
 glassesButton.setSelected(true);
 hairButton = new JCheckBox(\"Hair\");
 hairButton.setMnemonic(KeyEvent.VK_H);
 hairButton.setSelected(true);
 teethButton = new JCheckBox(\"Teeth\");
 teethButton.setMnemonic(KeyEvent.VK_T);
 teethButton.setSelected(true);
 //Register a listener for the check boxes.
 chinButton.addItemListener(this);
 glassesButton.addItemListener(this);
 hairButton.addItemListener(this);
 teethButton.addItemListener(this);
 //Indicates what\'s on the geek.
 choices = new StringBuffer(\"cght\");
 //Set up the picture label
 pictureLabel = new JLabel();
 pictureLabel.setFont(pictureLabel.getFont().deriveFont(Font.ITALIC));
 updatePicture();
 //Put the check boxes in a column in a panel
 JPanel checkPanel = new JPanel(new GridLayout(0, 1));
 checkPanel.add(chinButton);
 checkPanel.add(glassesButton);
 checkPanel.add(hairButton);
 checkPanel.add(teethButton);
 add(checkPanel, BorderLayout.LINE_START);
 add(pictureLabel, BorderLayout.CENTER);
 setBorder(BorderFactory.createEmptyBorder(20,20,20,20));
 }
 /** Listens to the check boxes. */
 public void itemStateChanged(ItemEvent e) {
 int index = 0;
 char c = \'-\';
 Object source = e.getItemSelectable();
 if (source == chinButton) {
 index = 0;
 c = \'c\';
 } else if (source == glassesButton) {
 index = 1;
 c = \'g\';
 } else if (source == hairButton) {
 index = 2;
 c = \'h\';
 } else if (source == teethButton) {
 index = 3;
 c = \'t\';
 }
 //Now that we know which button was pushed, find out
 //whether it was selected or deselected.
 if (e.getStateChange() == ItemEvent.DESELECTED) {
 c = \'-\';
 }
 //Apply the change to the string.
 choices.setCharAt(index, c);
 updatePicture();
 }
 protected void updatePicture() {
 //Get the icon corresponding to the image.
 ImageIcon icon = createImageIcon(
\"images/geek/geek-\"
 + choices.toString()
 +\".gif\");
 pictureLabel.setIcon(icon);
 pictureLabel.setToolTipText(choices.toString());
 if (icon == null) {
 pictureLabel.setText(\"Missing Image\");
 } else {
 pictureLabel.setText(null);
 }
 }
 /** Returns an ImageIcon, or null if the path was invalid. */
 protected static ImageIcon createImageIcon(String path) {
 java.net.URL imgURL = SwingCheckBoxDemo.class.getResource(path);
 if (imgURL != null) {
 return new ImageIcon(imgURL);
 } else {
 System.err.println(\"Couldn\'t find file:\" + path);
 return null;
 }
 }
 /**
 * 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.
 JFrame frame = new JFrame(\"SwingCheckBoxDemo\");
 frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
 //Create and set up the content pane.
 JComponent newContentPane = new SwingCheckBoxDemo();
 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();
 }
 });
 }
}
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