Federico Mena-Quintero

federico@ximian.com

GtkFileChooser, starting with GTK+ 2.4, is the new set of APIs for file selection widgets and dialogs. Previous versions of GTK+ used GtkFileSelection, which has numerous problems. GtkFileChooser is an abstract interface that can be implemented by widgets that perform file selection tasks. Two widgets in GTK+ implement this interface: GtkFileChooserDialog and GtkFileChooserWidget. Most applications simply need to use GtkFileChooserDialog, which is a dialog box that allows the user to select existing files for opening them, or to pick new filenames for saving documents. GtkFileChooserWidget is for special applications that need to embed a file selection widget inside a larger window. In the context of GTK+, GtkFileChooserDialog is simply a GtkDialog box with a GtkFileChooserWidget inside.

To create a GtkFileChooserDialog, you simply call gtk_file_chooser_dialog_new(). This function is similar to gtk_dialog_new() in that it takes parameters for the title of the dialog box and its transient parent, as well as its buttons. In addition, it takes in an argument that determines whether the file chooser dialog will be used for opening existing files or for saving to a possibly new file. Please see for how to create a simple file chooser dialog and extract the selected filename from it.

GtkFileChooser can be used in two modes, to select a single file at a time or to select a set of more than one file. To set this, use gtk_file_chooser_set_select_multiple(). In single-selection mode, you can use gtk_file_chooser_get_filename() to get a file name from the local file system or gtk_file_chooser_get_uri() to get a full-formed URI. In multiple-selection mode, you can use gtk_file_chooser_get_filenames() to get a GSList of filename strings, or gtk_file_chooser_get_uris() to get a list of URI strings. Also, you can configure GtkFileChooser to select files or folders. Consider a backup program that needs to let the user select a folder that will be backed up along with its subfolders. To configure whether GtkFileChooser is used to select files or folders, use gtk_file_chooser_set_action(). In addition, this lets you configure whether the file chooser will be used to select existing files or folders (e.g. for "File/Open"), or to type in new filenames (for "File/Save As...").

Many applications need to have a preview facility within their file chooser dialogs. Previous to GTK+ 2.4, one needed to access the GtkFileSelection widget hierarchy directly to hook in a preview widget. With GtkFileChooser, there is a dedicated API to do this. Please see the section on creating preview widgets for more information.

Some applications need to install extra widgets in a file chooser. For example, an application may want to provide a toggle button to give the user the option of opening a file read-only. Please see the section on creating extra widgets for more information.

New features in GtkFileChooser include the following: Ability to select URIs rather than just local files. You must use a GtkFileSystem implementation that supports this, for example the gnome-vfs backend. Present a list of application-specific shortcut folders. For example, a paint program may want to add a shortcut for its /usr/share/paint_program/Clipart folder. Define custom filters so that not all the files in a folder are listed. For example, you could filter out backup files, or show only image files. To see how to use these features, please consult the GtkFileChooser reference documentation.