Dialog boxes are a convenient way to prompt the user for a small amount of
input, e.g. to display a message, ask a question, or anything else that does
not require extensive effort on the user's part. GTK+ treats a dialog as a window split vertically. The top section is a
GtkVBox
, and is where widgets such as a GtkLabel
or a GtkEntry
should
be packed. The bottom area is known as the
action_area
. This is generally used for
packing buttons into the dialog which may perform functions such as
cancel, ok, or apply. The two areas are separated by a GtkHSeparator
.
GtkDialog
boxes are created with a call to gtkDialogNew
or
gtkDialogNewWithButtons
. gtkDialogNewWithButtons
is recommended; it
allows you to set the dialog title, some convenient flags, and add simple
buttons. If 'dialog' is a newly created dialog, the two primary areas of the window
can be accessed through gtkDialogGetContentArea
and
gtkDialogGetActionArea
, as can be seen from the example, below. A 'modal' dialog (that is, one which freezes the rest of the application from
user input), can be created by calling gtkWindowSetModal
on the dialog. Use
the gtkWindow()
function to cast the widget returned from gtkDialogNew
into a
GtkWindow
. When using gtkDialogNewWithButtons
you can also pass the
GTK_DIALOG_MODAL
flag to make a dialog modal. If you add buttons to GtkDialog
using gtkDialogNewWithButtons
,
gtkDialogAddButton
, gtkDialogAddButtons
, or
gtkDialogAddActionWidget
, clicking the button will emit a signal called
"response" with a response ID that you specified. GTK+ will never assign a
meaning to positive response IDs; these are entirely user-defined. But for
convenience, you can use the response IDs in the GtkResponseType
enumeration
(these all have values less than zero). If a dialog receives a delete event,
the "response" signal will be emitted with a response ID of GTK_RESPONSE_DELETE_EVENT
. If you want to block waiting for a dialog to return before returning control
flow to your code, you can call gtkDialogRun
. This function enters a
recursive main loop and waits for the user to respond to the dialog, returning the
response ID corresponding to the button the user clicked. For the simple dialog in the following example, in reality you'd probably use
GtkMessageDialog
to save yourself some effort. But you'd need to create the
dialog contents manually if you had more than a simple message in the dialog. Simple GtkDialog
usage.
# Function to open a dialog box displaying the message provided.
quick_message <- function(message) {
## Create the widgets dialog <- gtkDialog("Message", NULL, "destroy-with-parent",
"gtk-ok", GtkResponseType["none"],
show = FALSE)
label <- gtkLabel(message) ## Ensure that the dialog box is destroyed when the user responds. gSignalConnect(dialog, "response", gtkWidgetDestroy) ## Add the label, and show everything we've added to the dialog. dialog[["vbox"]]$add(label)
dialog$showAll()
}