GtkFileChooser is an interface that can be implemented by file
selection widgets. In GTK+, the main objects that implement this
interface are GtkFileChooserWidget, GtkFileChooserDialog, and
GtkFileChooserButton. You do not need to write an object that
implements the GtkFileChooser interface unless you are trying to
adapt an existing file selector to expose a standard programming
interface.
GtkFileChooser allows for shortcuts to various places in the filesystem.
In the default implementation these are displayed in the left pane. It
may be a bit confusing at first that these shortcuts come from various
sources and in various flavours, so lets explain the terminology here:
- Bookmarks
- undocumented
- Shortcuts
- undocumented
- Volumes
- undocumented
File Names and Encodings
When the user is finished selecting files in a
GtkFileChooser, your program can get the selected names
either as filenames or as URIs. For URIs, the normal escaping
rules are applied if the URI contains non-ASCII characters.
However, filenames are always returned in
the character set specified by the
G_FILENAME_ENCODING environment variable.
Please see the Glib documentation for more details about this
variable.
PLEASE NOTE: This means that while you can pass the result of
gtkFileChooserGetFilename to
open(2) or
fopen(3) , you may not be able to
directly set it as the text of a GtkLabel widget unless you
convert it first to UTF-8, which all GTK+ widgets expect.
You should use gFilenameToUtf8() to convert filenames
into strings that can be passed to GTK+ widgets. Adding a Preview Widget
You can add a custom preview widget to a file chooser and then
get notification about when the preview needs to be updated.
To install a preview widget, use
gtkFileChooserSetPreviewWidget. Then, connect to the
"update-preview" signal to get notified when
you need to update the contents of the preview. Your callback should use
gtkFileChooserGetPreviewFilename to see what needs
previewing. Once you have generated the preview for the
corresponding file, you must call
gtkFileChooserSetPreviewWidgetActive with a boolean
flag that indicates whether your callback could successfully
generate a preview. Sample Usage
update_preview_cb <- function(file_chooser, preview)
{
filename <- file_chooser$getPreviewFilename() pixbuf <- gdkPixbuf(file=filename, w=128, h=128)[[1]]
have_preview <- !is.null(pixbuf) preview$setFromPixbuf(pixbuf) file_chooser$setPreviewWidgetActive(have_preview)
} preview <- gtkImage()
my_file_chooser$setPreviewWidget(preview)
gSignalConnect(my_file_chooser, "update-preview", update_preview_cb, preview)
Adding Extra Widgets
You can add extra widgets to a file chooser to provide options
that are not present in the default design. For example, you
can add a toggle button to give the user the option to open a
file in read-only mode. You can use
gtkFileChooserSetExtraWidget to insert additional
widgets in a file chooser. Sample Usage
toggle <- gtkCheckButton("Open file read-only")
my_file_chooser$setExtraWidget(toggle)
PLEASE NOTE: If you want to set more than one extra widget in the file
chooser, you can a container such as a GtkVBox or a GtkTable
and include your widgets in it. Then, set the container as
the whole extra widget.
Key Bindings
Internally, GTK+ implements a file chooser's graphical user
interface with the private
GtkFileChooserDefaultClass. This
widget has several key
bindings and their associated signals. This section
describes the available key binding signals. GtkFileChooser key binding example
The default keys that activate the key-binding signals in
GtkFileChooserDefaultClass are as
follows:
|
Signal name |
| Default key combinations |
|
location-popup |
| Control-L (empty path);
/ (path of "/")
PLEASE NOTE: Both the individual / key and the
numeric keypad's "divide" key are supported.
;
~ (path of "~")
|
|
up-folder |
| Alt-Up PLEASE NOTE: Both the individual Up key and the numeric
keypad's Up key are supported. ;
Backspace
|
|
down-folder |
| Alt-Down |
|
home-folder |
| Alt-Home |
|
desktop-folder |
| Alt-D |
|
quick-bookmark |
| Alt-1 through Alt-0 |
You can change these defaults to something else. For
example, to add a Shift modifier to a few
of the default bindings, you can include the following
fragment in your ‘.gtkrc-2.0’ file:
binding "my-own-gtkfilechooser-bindings" {
bind "Up" {
"up-folder" ()
}
bind "Down" {
"down-folder" ()
}
bind "Home" {
"home-folder" ()
}
} class "GtkFileChooserDefault" binding "my-own-gtkfilechooser-bindings"
The "GtkFileChooserDefault::location-popup" signal void user_function (GtkFileChooserDefault *chooser,
const char *path,
gpointer user_data);
This is used to make the file chooser show a "Location"
dialog which the user can use to manually type the name of
the file he wishes to select. The
path argument is a string that gets
put in the text entry for the file name. By default this is bound to
Control-L
with a path string of "" (the empty
string). It is also bound to / with a
path string of "/"
(a slash): this lets you type / and
immediately type a path name. On Unix systems, this is bound to
~ (tilde) with a path string
of "~" itself for access to home directories.
chooser :- the object which received the signal.
path :- default contents for the text entry for the file name
user.data :- user data set when the signal handler was connected.
PLEASE NOTE: You can create your own bindings for the
GtkFileChooserDefault::location-popup signal with custom
path strings, and have a crude form
of easily-to-type bookmarks. For example, say you access
the path ‘/home/username/misc’ very
frequently. You could then create an Alt-M
shortcut by including the following in your
‘.gtkrc-2.0’ :
binding "misc-shortcut" {
bind "M" {
"location-popup" ("/home/username/misc")
}
} class "GtkFileChooserDefault" binding "misc-shortcut"
The "GtkFileChooserDefault::up-folder" signal void user_function (GtkFileChooserDefault *chooser,
gpointer user_data);
This is used to make the file chooser go to the parent of
the current folder in the file hierarchy. By default this
is bound to Backspace and
Alt-Up
(the Up key in the numeric keypad also works).
chooser :- the object which received the signal.
user.data :- user data set when the signal handler was connected.
The "GtkFileChooserDefault::down-folder" signal void user_function (GtkFileChooserDefault *chooser,
gpointer user_data);
This is used to make the file chooser go to a child of the
current folder in the file hierarchy. The subfolder that
will be used is displayed in the path bar widget of the file
chooser. For example, if the path bar is showing
"/foo/bar/baz", then this will cause
the file chooser to switch to the "baz" subfolder. By
default this is bound to
Alt-Down
(the Down key in the numeric keypad also works).
chooser :- the object which received the signal.
user.data :- user data set when the signal handler was connected.
The "GtkFileChooserDefault::home-folder" signal void user_function (GtkFileChooserDefault *chooser,
gpointer user_data);
This is used to make the file chooser show the user's home
folder in the file list. By default this is bound to
Alt-Home
(the Home key in the numeric keypad also works).
chooser :- the object which received the signal.
user.data :- user data set when the signal handler was connected.
The "GtkFileChooserDefault::desktop-folder" signal void user_function (GtkFileChooserDefault *chooser,
gpointer user_data);
This is used to make the file chooser show the user's Desktop
folder in the file list. By default this is bound to
Alt-D.
chooser :- the object which received the signal.
user.data :- user data set when the signal handler was connected.
The "GtkFileChooserDefault::quick-bookmark" signal void user_function (GtkFileChooserDefault *chooser,
gint bookmark_index,
gpointer user_data);
This is used to make the file chooser switch to the bookmark
specified in the bookmark.index parameter.
For example, if you have three bookmarks, you can pass 0, 1, 2 to
this signal to switch to each of them, respectively. By default this is bound to
Alt-1,
Alt-2,
etc. until
Alt-0. Note
that in the default binding,
that Alt-1 is
actually defined to switch to the bookmark at index 0, and so on
successively;
Alt-0 is
defined to switch to the bookmark at index 10.
chooser :- the object which received the signal.
bookmark.indes :- index of the bookmark to switch to; the indices start at 0.
user.data :- user data set when the signal handler was connected.