Java tutorial
import java.awt.BorderLayout; import java.awt.Dimension; import java.awt.Graphics; import java.awt.Image; import java.awt.Insets; import java.awt.event.ActionEvent; import java.awt.event.ActionListener; import java.beans.PropertyChangeEvent; import java.beans.PropertyChangeListener; import java.io.File; import javax.swing.Icon; import javax.swing.ImageIcon; import javax.swing.JButton; import javax.swing.JComponent; import javax.swing.JFileChooser; import javax.swing.JFrame; import javax.swing.JPanel; import javax.swing.JScrollPane; import javax.swing.JTextArea; import javax.swing.SwingUtilities; import javax.swing.UIManager; import javax.swing.filechooser.FileFilter; import javax.swing.filechooser.FileView; /* * FileChooserDemo2.java requires these files: * ImageFileView.java * ImageFilter.java * ImagePreview.java * Utils.java * images/jpgIcon.gif (required by ImageFileView.java) * images/gifIcon.gif (required by ImageFileView.java) * images/tiffIcon.gif (required by ImageFileView.java) * images/pngIcon.png (required by ImageFileView.java) */ public class FileChooserDemo2 extends JPanel implements ActionListener { static private String newline = "\n"; private JTextArea log; private JFileChooser fc; public FileChooserDemo2() { super(new BorderLayout()); // Create the log first, because the action listener // needs to refer to it. log = new JTextArea(5, 20); log.setMargin(new Insets(5, 5, 5, 5)); log.setEditable(false); JScrollPane logScrollPane = new JScrollPane(log); JButton sendButton = new JButton("Attach..."); sendButton.addActionListener(this); add(sendButton, BorderLayout.PAGE_START); add(logScrollPane, BorderLayout.CENTER); } public void actionPerformed(ActionEvent e) { // Set up the file chooser. if (fc == null) { fc = new JFileChooser(); // Add a custom file filter and disable the default // (Accept All) file filter. fc.addChoosableFileFilter(new ImageFilter()); fc.setAcceptAllFileFilterUsed(false); // Add custom icons for file types. fc.setFileView(new ImageFileView()); // Add the preview pane. fc.setAccessory(new ImagePreview(fc)); } // Show it. int returnVal = fc.showDialog(FileChooserDemo2.this, "Attach"); // Process the results. if (returnVal == JFileChooser.APPROVE_OPTION) { File file = fc.getSelectedFile(); log.append("Attaching file: " + file.getName() + "." + newline); } else { log.append("Attachment cancelled by user." + newline); } log.setCaretPosition(log.getDocument().getLength()); // Reset the file chooser for the next time it's shown. fc.setSelectedFile(null); } /** * Create the GUI and show it. For thread safety, this method should be * invoked from the event dispatch thread. */ private static void createAndShowGUI() { // Create and set up the window. JFrame frame = new JFrame("FileChooserDemo2"); frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); // Add content to the window. frame.add(new FileChooserDemo2()); // Display the window. frame.pack(); frame.setVisible(true); } public static void main(String[] args) { // Schedule a job for the event dispatch thread: // creating and showing this application's GUI. SwingUtilities.invokeLater(new Runnable() { public void run() { // Turn off metal's use of bold fonts UIManager.put("swing.boldMetal", Boolean.FALSE); createAndShowGUI(); } }); } } /* * 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. */ class ImageFileView extends FileView { ImageIcon jpgIcon = Utils.createImageIcon("images/jpgIcon.gif"); ImageIcon gifIcon = Utils.createImageIcon("images/gifIcon.gif"); ImageIcon tiffIcon = Utils.createImageIcon("images/tiffIcon.gif"); ImageIcon pngIcon = Utils.createImageIcon("images/pngIcon.png"); public String getName(File f) { return null; // let the L&F FileView figure this out } public String getDescription(File f) { return null; // let the L&F FileView figure this out } public Boolean isTraversable(File f) { return null; // let the L&F FileView figure this out } public String getTypeDescription(File f) { String extension = Utils.getExtension(f); String type = null; if (extension != null) { if (extension.equals(Utils.jpeg) || extension.equals(Utils.jpg)) { type = "JPEG Image"; } else if (extension.equals(Utils.gif)) { type = "GIF Image"; } else if (extension.equals(Utils.tiff) || extension.equals(Utils.tif)) { type = "TIFF Image"; } else if (extension.equals(Utils.png)) { type = "PNG Image"; } } return type; } public Icon getIcon(File f) { String extension = Utils.getExtension(f); Icon icon = null; if (extension != null) { if (extension.equals(Utils.jpeg) || extension.equals(Utils.jpg)) { icon = jpgIcon; } else if (extension.equals(Utils.gif)) { icon = gifIcon; } else if (extension.equals(Utils.tiff) || extension.equals(Utils.tif)) { icon = tiffIcon; } else if (extension.equals(Utils.png)) { icon = pngIcon; } } return icon; } } /* * 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. */ class ImageFilter extends FileFilter { // Accept all directories and all gif, jpg, tiff, or png files. public boolean accept(File f) { if (f.isDirectory()) { return true; } String extension = Utils.getExtension(f); if (extension != null) { if (extension.equals(Utils.tiff) || extension.equals(Utils.tif) || extension.equals(Utils.gif) || extension.equals(Utils.jpeg) || extension.equals(Utils.jpg) || extension.equals(Utils.png)) { return true; } else { return false; } } return false; } // The description of this filter public String getDescription() { return "Just Images"; } } /* * 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. */ class ImagePreview extends JComponent implements PropertyChangeListener { ImageIcon thumbnail = null; File file = null; public ImagePreview(JFileChooser fc) { setPreferredSize(new Dimension(100, 50)); fc.addPropertyChangeListener(this); } public void loadImage() { if (file == null) { thumbnail = null; return; } // Don't use createImageIcon (which is a wrapper for getResource) // because the image we're trying to load is probably not one // of this program's own resources. ImageIcon tmpIcon = new ImageIcon(file.getPath()); if (tmpIcon != null) { if (tmpIcon.getIconWidth() > 90) { thumbnail = new ImageIcon(tmpIcon.getImage().getScaledInstance(90, -1, Image.SCALE_DEFAULT)); } else { // no need to miniaturize thumbnail = tmpIcon; } } } public void propertyChange(PropertyChangeEvent e) { boolean update = false; String prop = e.getPropertyName(); // If the directory changed, don't show an image. if (JFileChooser.DIRECTORY_CHANGED_PROPERTY.equals(prop)) { file = null; update = true; // If a file became selected, find out which one. } else if (JFileChooser.SELECTED_FILE_CHANGED_PROPERTY.equals(prop)) { file = (File) e.getNewValue(); update = true; } // Update the preview accordingly. if (update) { thumbnail = null; if (isShowing()) { loadImage(); repaint(); } } } protected void paintComponent(Graphics g) { if (thumbnail == null) { loadImage(); } if (thumbnail != null) { int x = getWidth() / 2 - thumbnail.getIconWidth() / 2; int y = getHeight() / 2 - thumbnail.getIconHeight() / 2; if (y < 0) { y = 0; } if (x < 5) { x = 5; } thumbnail.paintIcon(this, g, x, y); } } } /* * 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. */ /* Utils.java is used by FileChooserDemo2.java. */ class Utils { public final static String jpeg = "jpeg"; public final static String jpg = "jpg"; public final static String gif = "gif"; public final static String tiff = "tiff"; public final static String tif = "tif"; public final static String png = "png"; /* * Get the extension of a file. */ public static String getExtension(File f) { String ext = null; String s = f.getName(); int i = s.lastIndexOf('.'); if (i > 0 && i < s.length() - 1) { ext = s.substring(i + 1).toLowerCase(); } return ext; } /** Returns an ImageIcon, or null if the path was invalid. */ protected static ImageIcon createImageIcon(String path) { java.net.URL imgURL = Utils.class.getResource(path); if (imgURL != null) { return new ImageIcon(imgURL); } else { System.err.println("Couldn't find file: " + path); return null; } } }