| Allegro CL version 8.2 Unrevised from 8.1 to 8.2. 8.1 version |
Arguments: windows-button
Returns the value of the cluster property of windows-button. This
property groups picture-button
or radio-button
controls
into clusters (and also menu-items, see below). If a user clicks one
button in the cluster, that button will be turned on and all other
buttons in the cluster turned off.
Clusters are logical associations independent of physical placement on
the dialog, but controls must be on the same dialog to be in the same
cluster. All of the buttons in a single cluster will have an identical
Lisp symbol (such as :cluster-1
or
:send-form-button-panel
) in their cluster
property. The controls are also often arranged visually as a group,
perhaps in a group-box
.
The cluster property can also be used with menu-item
s. A set of contiguous
menu-items can act like a set of radio-buttons, where calling
(setf selected)
to mark one of the menu-items as selected automatically
deselects all of the other menu-items in the group. The group is set
up by setting the cluster property of each menu-item in the group to
the same arbitrary symbol, just as with radio-button widgets. In
addition, a menu-item whose cluster property is non-nil will be marked
by a small round dot when selected rather than with a check mark. It
is a good idea to place a menu-separator between the menu-items in a
cluster and any other menu-items on the same menu to clarify to the end
user which items are in the group.
In the following example, each time (pop-up-menu
my-menu)
is called and a menu-item is selected, the menu's
on-click function
toggles whether that item is selected, which is apparent only when the
menu is shown a further time. The "Independent" item is not in a
cluster, while the other two items are in a cluster named
:a. Selecting one of the items in the cluster will unselect the other
item in the cluster if it was selected, but will not unselect the
"Independent" item if it was selected.
(defparameter my-menu nil) (setq my-menu (open-menu (list (make-instance 'menu-item :title "Independent") menu-separator (make-instance 'menu-item :title "One" :cluster :a) (make-instance 'menu-item :title "The Other" :cluster :a)) 'pop-up-menu (screen *system*) :on-click #'(lambda (menu menu-item stream) (declare (ignore menu stream)) (setf (selected menu-item) (not (selected menu-item))) (title menu-item)))) (pop-up-menu my-menu) ;; call this multiple times
cluster is a
property of the picture-button
, radio-button
, and
menu-item
classes.
GTK requires that one radio-button
in a cluster always be on. If you
set the value of the
radio-button that's "on" to nil
, then GTK
will automatically turn on the first radio-button in the cluster.
Copyright (c) 1998-2016, Franz Inc. Oakland, CA., USA. All rights reserved.
This page was not revised from the 8.1 page.
Created 2010.1.21.
| Allegro CL version 8.2 Unrevised from 8.1 to 8.2. 8.1 version |