A file view that displays an icon for all files that match a file filter
/*
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);
}
}
});
}
}
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