FileChooserTest.java Source code

Introduction

Here is the source code for FileChooserTest.java

Source

/*
   This program is a part of the companion code for Core Java 8th ed.
   (http://horstmann.com/corejava)
    
   This program is free software: you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation, either version 3 of the License, or
   (at your option) any later version.
    
   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.
    
   You should have received a copy of the GNU General Public License
   along with this program.  If not, see <http://www.gnu.org/licenses/>.
*/

import java.awt.Dimension;
import java.awt.EventQueue;
import java.awt.Image;
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.BorderFactory;
import javax.swing.Icon;
import javax.swing.ImageIcon;
import javax.swing.JFileChooser;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JMenu;
import javax.swing.JMenuBar;
import javax.swing.JMenuItem;
import javax.swing.filechooser.FileFilter;
import javax.swing.filechooser.FileNameExtensionFilter;
import javax.swing.filechooser.FileView;

/**
 * @version 1.23 2007-06-12
 * @author Cay Horstmann
 */
public class FileChooserTest {
    public static void main(String[] args) {
        EventQueue.invokeLater(new Runnable() {
            public void run() {
                ImageViewerFrame frame = new ImageViewerFrame();
                frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
                frame.setVisible(true);
            }
        });
    }
}

/**
 * A frame that has a menu for loading an image and a display area for the loaded image.
 */
class ImageViewerFrame extends JFrame {
    public ImageViewerFrame() {
        setTitle("FileChooserTest");
        setSize(DEFAULT_WIDTH, DEFAULT_HEIGHT);

        // set up menu bar
        JMenuBar menuBar = new JMenuBar();
        setJMenuBar(menuBar);

        JMenu menu = new JMenu("File");
        menuBar.add(menu);

        JMenuItem openItem = new JMenuItem("Open");
        menu.add(openItem);
        openItem.addActionListener(new FileOpenListener());

        JMenuItem exitItem = new JMenuItem("Exit");
        menu.add(exitItem);
        exitItem.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent event) {
                System.exit(0);
            }
        });

        // use a label to display the images
        label = new JLabel();
        add(label);

        // set up file chooser
        chooser = new JFileChooser();

        // accept all image files ending with .jpg, .jpeg, .gif
        /*
        final ExtensionFileFilter filter = new ExtensionFileFilter();
        filter.addExtension("jpg");
        filter.addExtension("jpeg");
        filter.addExtension("gif");
        filter.setDescription("Image files");
        */
        FileNameExtensionFilter filter = new FileNameExtensionFilter("Image files", "jpg", "jpeg", "gif");
        chooser.setFileFilter(filter);

        chooser.setAccessory(new ImagePreviewer(chooser));

        chooser.setFileView(new FileIconView(filter, new ImageIcon("palette.gif")));
    }

    /**
     * This is the listener for the File->Open menu item.
     */
    private class FileOpenListener implements ActionListener {
        public void actionPerformed(ActionEvent event) {
            chooser.setCurrentDirectory(new File("."));

            // show file chooser dialog
            int result = chooser.showOpenDialog(ImageViewerFrame.this);

            // if image file accepted, set it as icon of the label
            if (result == JFileChooser.APPROVE_OPTION) {
                String name = chooser.getSelectedFile().getPath();
                label.setIcon(new ImageIcon(name));
            }
        }
    }

    public static final int DEFAULT_WIDTH = 300;
    public static final int DEFAULT_HEIGHT = 400;

    private JLabel label;
    private JFileChooser chooser;
}

/**
 * A file view that displays an icon for all files that match a file filter.
 */
class FileIconView extends FileView {
    /**
     * Constructs a FileIconView.
     * @param aFilter a file filter--all files that this filter accepts will be shown with the icon.
     * @param anIcon--the icon shown with all accepted files.
     */
    public FileIconView(FileFilter aFilter, Icon anIcon) {
        filter = aFilter;
        icon = anIcon;
    }

    public Icon getIcon(File f) {
        if (!f.isDirectory() && filter.accept(f))
            return icon;
        else
            return null;
    }

    private FileFilter filter;
    private Icon icon;
}

/**
 * A file chooser accessory that previews images.
 */
class ImagePreviewer extends JLabel {
    /**
     * Constructs an ImagePreviewer.
     * @param chooser the file chooser whose property changes trigger an image change in this
     * previewer
     */
    public ImagePreviewer(JFileChooser chooser) {
        setPreferredSize(new Dimension(100, 100));
        setBorder(BorderFactory.createEtchedBorder());

        chooser.addPropertyChangeListener(new PropertyChangeListener() {
            public void propertyChange(PropertyChangeEvent event) {
                if (event.getPropertyName() == JFileChooser.SELECTED_FILE_CHANGED_PROPERTY) {
                    // the user has selected a new file
                    File f = (File) event.getNewValue();
                    if (f == null) {
                        setIcon(null);
                        return;
                    }

                    // read the image into an icon
                    ImageIcon icon = new ImageIcon(f.getPath());

                    // if the icon is too large to fit, scale it
                    if (icon.getIconWidth() > getWidth())
                        icon = new ImageIcon(
                                icon.getImage().getScaledInstance(getWidth(), -1, Image.SCALE_DEFAULT));

                    setIcon(icon);
                }
            }
        });
    }
}