Java tutorial
/* * Copyright (c) 1995 - 2008 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: * * - 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 Sun Microsystems nor 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. */ import java.awt.BasicStroke; import java.awt.BorderLayout; import java.awt.Color; import java.awt.Component; import java.awt.Graphics; import java.awt.Graphics2D; import java.awt.Image; import java.awt.RenderingHints; import java.awt.event.ActionEvent; import java.awt.image.BufferedImage; import java.util.List; import javax.swing.AbstractAction; import javax.swing.BorderFactory; import javax.swing.Box; import javax.swing.Icon; import javax.swing.ImageIcon; import javax.swing.JButton; import javax.swing.JFrame; import javax.swing.JLabel; import javax.swing.JToolBar; import javax.swing.SwingUtilities; import javax.swing.SwingWorker; /** * This application is intended to demonstrate the loading of image files into * icons for use in a Swing user interface. It creates a toolbar with a * thumbnail preview of each image. Clicking on the thumbnail will show the full * image in the main display area. * * IconDemoApp.java requires the following files: <br> * The following files are copyright 2006 spriggs.net and licensed under a * Creative Commons License (http://creativecommons.org/licenses/by-sa/3.0/) * <br> * images/sunw01.jpg <br> * images/sunw02.jpg <br> * images/sunw03.jpg <br> * images/sunw04.jpg <br> * images/sunw05.jpg <br> * * @author Collin Fagan * @date 7/25/2007 * @version 2.0 */ public class IconDemoApp extends JFrame { private JLabel photographLabel = new JLabel(); private JToolBar buttonBar = new JToolBar(); private String imagedir = "images/"; private MissingIcon placeholderIcon = new MissingIcon(); /** * List of all the descriptions of the image files. These correspond one to * one with the image file names */ private String[] imageCaptions = { "Original SUNW Logo", "The Clocktower", "Clocktower from the West", "The Mansion", "Sun Auditorium" }; /** * List of all the image files to load. */ private String[] imageFileNames = { "sunw01.jpg", "sunw02.jpg", "sunw03.jpg", "sunw04.jpg", "sunw05.jpg" }; /** * Main entry point to the demo. Loads the Swing elements on the "Event * Dispatch Thread". * * @param args */ public static void main(String args[]) { SwingUtilities.invokeLater(new Runnable() { public void run() { IconDemoApp app = new IconDemoApp(); app.setVisible(true); } }); } /** * Default constructor for the demo. */ public IconDemoApp() { setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); setTitle("Icon Demo: Please Select an Image"); // A label for displaying the pictures photographLabel.setVerticalTextPosition(JLabel.BOTTOM); photographLabel.setHorizontalTextPosition(JLabel.CENTER); photographLabel.setHorizontalAlignment(JLabel.CENTER); photographLabel.setBorder(BorderFactory.createEmptyBorder(5, 5, 5, 5)); // We add two glue components. Later in process() we will add thumbnail // buttons // to the toolbar inbetween thease glue compoents. This will center the // buttons in the toolbar. buttonBar.add(Box.createGlue()); buttonBar.add(Box.createGlue()); add(buttonBar, BorderLayout.SOUTH); add(photographLabel, BorderLayout.CENTER); setSize(400, 300); // this centers the frame on the screen setLocationRelativeTo(null); // start the image loading SwingWorker in a background thread loadimages.execute(); } /** * SwingWorker class that loads the images a background thread and calls * publish when a new one is ready to be displayed. * * We use Void as the first SwingWroker param as we do not need to return * anything from doInBackground(). */ private SwingWorker<Void, ThumbnailAction> loadimages = new SwingWorker<Void, ThumbnailAction>() { /** * Creates full size and thumbnail versions of the target image files. */ @Override protected Void doInBackground() throws Exception { for (int i = 0; i < imageCaptions.length; i++) { ImageIcon icon; icon = createImageIcon(imagedir + imageFileNames[i], imageCaptions[i]); ThumbnailAction thumbAction; if (icon != null) { ImageIcon thumbnailIcon = new ImageIcon(getScaledImage(icon.getImage(), 32, 32)); thumbAction = new ThumbnailAction(icon, thumbnailIcon, imageCaptions[i]); } else { // the image failed to load for some reason // so load a placeholder instead thumbAction = new ThumbnailAction(placeholderIcon, placeholderIcon, imageCaptions[i]); } publish(thumbAction); } // unfortunately we must return something, and only null is valid to // return when the return type is void. return null; } /** * Process all loaded images. */ @Override protected void process(List<ThumbnailAction> chunks) { for (ThumbnailAction thumbAction : chunks) { JButton thumbButton = new JButton(thumbAction); // add the new button BEFORE the last glue // this centers the buttons in the toolbar buttonBar.add(thumbButton, buttonBar.getComponentCount() - 1); } } }; /** * Creates an ImageIcon if the path is valid. * * @param String - * resource path * @param String - * description of the file */ protected ImageIcon createImageIcon(String path, String description) { java.net.URL imgURL = getClass().getResource(path); if (imgURL != null) { return new ImageIcon(imgURL, description); } else { System.err.println("Couldn't find file: " + path); return null; } } /** * Resizes an image using a Graphics2D object backed by a BufferedImage. * * @param srcImg - * source image to scale * @param w - * desired width * @param h - * desired height * @return - the new resized image */ private Image getScaledImage(Image srcImg, int w, int h) { BufferedImage resizedImg = new BufferedImage(w, h, BufferedImage.TYPE_INT_RGB); Graphics2D g2 = resizedImg.createGraphics(); g2.setRenderingHint(RenderingHints.KEY_INTERPOLATION, RenderingHints.VALUE_INTERPOLATION_BILINEAR); g2.drawImage(srcImg, 0, 0, w, h, null); g2.dispose(); return resizedImg; } /** * Action class that shows the image specified in it's constructor. */ private class ThumbnailAction extends AbstractAction { /** * The icon if the full image we want to display. */ private Icon displayPhoto; /** * @param Icon - * The full size photo to show in the button. * @param Icon - * The thumbnail to show in the button. * @param String - * The descriptioon of the icon. */ public ThumbnailAction(Icon photo, Icon thumb, String desc) { displayPhoto = photo; // The short description becomes the tooltip of a button. putValue(SHORT_DESCRIPTION, desc); // The LARGE_ICON_KEY is the key for setting the // icon when an Action is applied to a button. putValue(LARGE_ICON_KEY, thumb); } /** * Shows the full image in the main area and sets the application title. */ public void actionPerformed(ActionEvent e) { photographLabel.setIcon(displayPhoto); setTitle("Icon Demo: " + getValue(SHORT_DESCRIPTION).toString()); } } } /* * Copyright (c) 1995 - 2008 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: * - 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 Sun Microsystems nor 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. */ /** * The "missing icon" is a white box with a black border and a red x. It's used * to display something when there are issues loading an icon from an external * location. * * @author Collin Fagan * @date 7/25/2007 */ class MissingIcon implements Icon { private int width = 32; private int height = 32; private BasicStroke stroke = new BasicStroke(4); public void paintIcon(Component c, Graphics g, int x, int y) { Graphics2D g2d = (Graphics2D) g.create(); g2d.setColor(Color.WHITE); g2d.fillRect(x + 1, y + 1, width - 2, height - 2); g2d.setColor(Color.BLACK); g2d.drawRect(x + 1, y + 1, width - 2, height - 2); g2d.setColor(Color.RED); g2d.setStroke(stroke); g2d.drawLine(x + 10, y + 10, x + width - 10, y + height - 10); g2d.drawLine(x + 10, y + height - 10, x + width - 10, y + 10); g2d.dispose(); } public int getIconWidth() { return width; } public int getIconHeight() { return height; } }