Java tutorial
/* 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. * * -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 * nuclear facility. */ import java.awt.BorderLayout; import java.awt.Insets; import java.awt.event.ActionEvent; import java.awt.event.ActionListener; import java.io.File; import javax.swing.ImageIcon; import javax.swing.JButton; import javax.swing.JComponent; import javax.swing.JDialog; import javax.swing.JFileChooser; import javax.swing.JFrame; import javax.swing.JPanel; import javax.swing.JScrollPane; import javax.swing.JTextArea; /* * SwingFileChooserDemo.java is a 1.4 application that uses these files: * images/Open16.gif images/Save16.gif */ public class SwingFileChooserDemo extends JPanel implements ActionListener { static private final String newline = "\n"; JButton openButton, saveButton; JTextArea log; JFileChooser fc; public SwingFileChooserDemo() { super(new BorderLayout()); //Create the log first, because the action listeners //need 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); //Create a file chooser fc = new JFileChooser(); //Uncomment one of the following lines to try a different //file selection mode. The first allows just directories //to be selected (and, at least in the Java look and feel, //shown). The second allows both files and directories //to be selected. If you leave these lines commented out, //then the default mode (FILES_ONLY) will be used. // //fc.setFileSelectionMode(JFileChooser.DIRECTORIES_ONLY); //fc.setFileSelectionMode(JFileChooser.FILES_AND_DIRECTORIES); //Create the open button. We use the image from the JLF //Graphics Repository (but we extracted it from the jar). openButton = new JButton("Open a File...", createImageIcon("images/Open16.gif")); openButton.addActionListener(this); //Create the save button. We use the image from the JLF //Graphics Repository (but we extracted it from the jar). saveButton = new JButton("Save a File...", createImageIcon("images/Save16.gif")); saveButton.addActionListener(this); //For layout purposes, put the buttons in a separate panel JPanel buttonPanel = new JPanel(); //use FlowLayout buttonPanel.add(openButton); buttonPanel.add(saveButton); //Add the buttons and the log to this panel. add(buttonPanel, BorderLayout.PAGE_START); add(logScrollPane, BorderLayout.CENTER); } public void actionPerformed(ActionEvent e) { //Handle open button action. if (e.getSource() == openButton) { int returnVal = fc.showOpenDialog(SwingFileChooserDemo.this); if (returnVal == JFileChooser.APPROVE_OPTION) { File file = fc.getSelectedFile(); //This is where a real application would open the file. log.append("Opening: " + file.getName() + "." + newline); } else { log.append("Open command cancelled by user." + newline); } log.setCaretPosition(log.getDocument().getLength()); //Handle save button action. } else if (e.getSource() == saveButton) { int returnVal = fc.showSaveDialog(SwingFileChooserDemo.this); if (returnVal == JFileChooser.APPROVE_OPTION) { File file = fc.getSelectedFile(); //This is where a real application would save the file. log.append("Saving: " + file.getName() + "." + newline); } else { log.append("Save command cancelled by user." + newline); } log.setCaretPosition(log.getDocument().getLength()); } } /** Returns an ImageIcon, or null if the path was invalid. */ protected static ImageIcon createImageIcon(String path) { java.net.URL imgURL = SwingFileChooserDemo.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); JDialog.setDefaultLookAndFeelDecorated(true); //Create and set up the window. JFrame frame = new JFrame("SwingFileChooserDemo"); frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); //Create and set up the content pane. JComponent newContentPane = new SwingFileChooserDemo(); 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(); } }); } }