How to select default FileFilter when creating a JFileChooser dialog?

Question

Good afternoon all,

I have an instance of a javax.swing.JFileChooser and I added a few choosable javax.swing.FileFilters using addChoosableFileFilter.

However when I show the dialog (through showSaveDialog), my custom choosable FileFilter is not selected by default.

I wanted to select the filter "Image Files" by default..

How do we select a default filter for the javax.swing.JFileChooser dialog?

SSCCEd:

public static void main(String args[]) {
    java.awt.EventQueue.invokeLater(new java.lang.Runnable() {
        @Override
        public void run() {
            new javax.swing.JFrame() {
                {
                    final javax.swing.JButton button = new javax.swing.JButton("Save");
                    button.addMouseListener(new java.awt.event.MouseAdapter() {
                        @Override
                        public void mousePressed(java.awt.event.MouseEvent e) {
                            new javax.swing.JFileChooser() {
                                {
                                    addChoosableFileFilter(NewFileFilter("Text Files", new String[] { "txt" }));
                                    addChoosableFileFilter(NewFileFilter("Image Files", new String[] { "gif", "png", "jpg" }));
                                    addChoosableFileFilter(NewFileFilter("Audio Files", new String[] { "mp3" }));
                                    addChoosableFileFilter(NewFileFilter("Video Files", new String[] { "mp4", "avi" }));
                                    showSaveDialog(button);
                                }

                                private javax.swing.filechooser.FileFilter NewFileFilter(final String desc, final String[] allowed_extensions) {
                                    return new javax.swing.filechooser.FileFilter() {
                                        @Override
                                        public boolean accept(java.io.File f) {
                                            if (f.isDirectory()) {
                                                return true;
                                            }
                                            int pos = f.getName().lastIndexOf('.');
                                            if (pos == -1) {
                                                return false;
                                            } else {
                                                String extension = f.getName().substring(pos + 1);
                                                for (String allowed_extension : allowed_extensions) {
                                                    if (extension.equalsIgnoreCase(allowed_extension)) {
                                                        return true;
                                                    }
                                                }
                                                return false;
                                            }
                                        }

                                        @Override
                                        public String getDescription() {
                                            return desc;
                                        }
                                    };
                                }
                            };
                        }
                    });
                    add(button);
                    setSize(100, 100);
                    setVisible(true);
                }
            };
        }
    });
}

Tenancy

Answer 1

Using setFileFilter():

FileFilter ff = NewFileFilter("Image Files", new String[] { "gif", "png", "jpg" });
addChoosableFileFilter(ff);
setFileFilter(ff);

Why are you subclassing the file chooser, rather than just using it? And why aren't you respecting Java's naming conventions (methods start with a lower-case letter)? And why don't you respect Swing's threading policy, which say that Swing components must be used in the EDT only.

Liking

Added javax.swing.SwingUtilities.invokeLater in the example. Why should methods be camelCased and not PascalCased? – Tenancy

Code Conventions for the Java – Korella

Because that's the standard convention in Java. – Liking

Answer 2

FileFilter filter = new FileNameExtensionFilter("Data Files", "*.dat"); 
JFileChooser fc   = new JFileChooser(); 
fc.addChoosableFileFilter(filter); 
fc.setMultiSelectionEnabled(false);

Foret

Please format your code properly, an add some details to your answer. – Commissioner