gio:action, gobject:object, common-lisp:standard-object, common-lisp:t

None

The g:simple-action class is the obvious simple implementation of the g:action interface. This is the easiest way to create an action for purposes of adding it to a g:simple-action-group object.

The "activate" signal

lambda (action parameter)    :run-last      

action

The g:simple-action object.

parameter

The g:variant parameter to the activation.

Indicates that the action was just activated. The parameter argument will always be of the expected type. In the event that an incorrect type was given, no signal will be emitted.

The "change-state" signal

lambda (action value)    :run-last      

action

The g:simple-action object.

value

The requested g:variant parameter for the state.

Indicates that the action just received a request to change its state. The value argument will always be of the correct state type. In the event that an incorrect type was given, no signal will be emitted. If no handler is connected to this signal then the default behaviour is to call the g:simple-action-state function to set the state to the requested value. If you connect a signal handler then no default action is taken. If the state should change then you must call the g:simple-action-state function from the handler.

Examples: Implementation of a "change-state" signal handler:

(g:signal-connect action "change-state"
                  (lambda (simple value)
                    (let ((requested (g:variant-int32 value)))
                      ;; Volume only goes from 0 to 10
                      (when (and (>= requested 0) (<= requested 10))
                        (setf (g:simple-action-state simple) value)))))      

The handler need not set the state to the requested value. It could set it to any value at all, or take some other action.