Page 324 Table of Contents Index Page 326
Chapters
1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30
A, B, C, D, E


CHAPTER 30. GADGETS

spectively, the initial value and the value changed callback of the gadget.

=> gadget-value value-gadget [Generic Function]
Returns the value of the gadget value-gadget. The interpretation of the value varies from gadget
to gadget. For example, a scroll bar's value might be a number between 0 and 1, while a toggle
button's value is either t or nil. (The documentation of each individual gadget below specifies
how to interpret the value.)

=> (setf gadget-value) value value-gadget &key invoke-callback [Generic Function]
Sets the gadget's value to the specified value. In addition, if invoke-callback is true, the value
changed callback for the gadget is invoked. The default is false. The syntax for using (setf gadget-
value) in conjunction with invoke-callback is:
 
 (setf (gadget-value gadget :invoke-callback t) new-value)
=> gadget-value-changed-callback value-gadget [Generic Function]
Returns the function that will be called when the value changed callback is invoked. This
function will be invoked with a two arguments, the gadget and the new value.

When this function returns nil, that indicates that there is no value changed callback for the
gadget.

=> value-changed-callback value-gadget client gadget-id value [Callback Generic Function]
This callback is invoked when the value of a gadget is changed, either by the user or programat-
ically.

The default method (on value-gadget) calls the function stored in gadget-value-changed-
callback with two arguments, the gadget and the new value.

CLIM implementations must implement or inherit a method for value-changed-callback for
every gadget that is a subclass of value-gadget.

=> action-gadget [Class]
The class used by gadgets that perform some kind of action, such as a push button; a subclass
of standard-gadget.

=> :activate-callback [Init Arg]
All subclasses of action-gadget must handle this initarg, which is used to specify the activate
callback of the gadget.

=> gadget-activate-callback action-gadget [Generic Function]
Returns the function that will be called when the gadget is activated. This function will be
invoked with one argument, the gadget.

Page 324 Table of Contents Index Page 326
Chapters
1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30
A, B, C, D, E