Now for the tricky part. You have to prepare yourself
to handle anything the user might do to your dialog.
Here's a brief list of possibilities; it's worth going
over the list whenever you create a dialog:
Closing the dialog by pressing the Escape key
Closing the dialog by clicking the window manager's
Clicking one of the dialog's buttons
Interacting with the contents of the dialog
If the dialog is not modal, interacting with other
parts of the application
GnomeDialog emits two
signals in addition to those it inherits from parent
classes. If the user clicks one of the dialog's
buttons, a "clicked" signal
is emitted. (This is not the
"clicked" signal from GtkButton; it's a different
signal, emitted by
handler should have three arguments: the dialog
emitting the signal, the number of the button clicked,
and your callback data.
GnomeDialog also has a "close" signal. It is emitted
when gnome_dialog_close() is
called; all the built-in event handlers (e.g. for the
Escape shortcut) call this function to close the
default handler for "close"
has two possible behaviors: it can call either gtk_widget_hide() or gtk_widget_destroy() on the dialog. The
behavior is configurable by calling gnome_dialog_close_hides(), shown in Figure 3.
gnome_dialog_set_close(GnomeDialog* dialog, gboolean setting);
Figure 3. Closing
By default, "close"
destroys the dialog. This is what you usually want;
however, if a dialog is noticeably time-consuming to
create, you might want to merely hide and re-show it
between uses, without ever destroying it. You might
also want to hide the dialog from the user, extract the
state of any widgets inside it, and then destroy it
The decision depends on the structure of your code.
However, in general it is simpler and less error-prone
to let the dialog be destroyed when clicked. You can
connect to the "clicked"
signal if you need to query the state of widgets in the
If you connect a handler to
"close", that handler should return a boolean
value. If it returns
TRUE, the hide or destroy will not take place.
You can use this to keep the user from closing the
dialog, for example if they have not filled in all the
fields of a form.
The "close" signal is
designed to collect several possible user actions into
a single handler: it should be emitted when the user
presses Escape or the window manager's window close
button is clicked. It's often convenient to emit close
when the dialog's buttons are clicked as well. You can
ask GnomeDialog to emit
close whenever a button is clicked with gnome_dialog_set_close() (Figure 3); if
its setting argument is
TRUE, the dialog will
emit "close" in addition to
"clicked" if any of its
buttons are clicked. By default, this setting is FALSE for GnomeDialog, but for many of the
special dialog types the default is TRUE (the inconsistency is an
Note that the "close"
signal is emitted when the dialog receives "delete_event"; this means you only
have to write one signal handler to deal with all
dialog closings. There is no need to handle "delete_event" as a separate