Activatable widgets can be connected to a GtkAction and reflects
the state of its action. A GtkActivatable can also provide feedback
through its action, as they are responsible for activating their
related actions. Implementing GtkActivatable
When extending a class that is already GtkActivatable; it is only
necessary to implement the GtkActivatable->syncActionProperties()
and GtkActivatable->update() methods and chain up to the parent
implementation, however when introducing
a new GtkActivatable class; the "related-action" and
"use-action-appearance" properties need to be handled by
the implementor. Handling these properties is mostly a matter of installing
the action pointer and boolean flag on your instance, and calling
gtkActivatableDoSetRelatedAction and
gtkActivatableSyncActionProperties at the appropriate times. A class fragment implementing GtkActivatable
gClass("FooBar", "GtkButton",
.prop_overrides=c("related-action", "use-action-appearance"),
GObject=list(
dispose=function(object) {
object$doSetRelatedAction(NULL)
},
set_property=function(object, id, value, pspec) {
if (pspec$name == "related-action") {
assignProp(object, pspec, value)
object$doSetRelatedAction(value)
} else if (pspec$name == "use-action-appearance") {
if (value != getProp(pspec)) {
assignProp(object, pspec, value)
object$syncActionProperties(object$"related-action")
}
} else {
warning("invalid property: ", pspec$name)
}
}
),
GtkActivatable=list(
sync_action_properties=function(activatable, action) {
if (is.null(action)) {
return()
}
activatable$visible <- action$visible
activatable$sensitive <- action$sensitive
## ...
if (activatable$use_action_appearance) {
if (!is.null(action$stock_id)) {
activatable$label <- action$stock_id
} else {
activatable$label <- action$label
}
activatable$use_stock <- !is.null(action$stock_id)
}
## ...
},
update=function(activatable, action, property_name) {
if (property_name == "visible") {
activatable$visible <- action$visible
} else if (property_name == "sensitive") {
activatable$sensitive <- action$sensitive
}
## ...
if (activatable$use_action_appearance) {
if (property_name == "stock-id") {
activatable$label <- action$stock_id
activatable$use_stock <- !is.null(action$stock_id)
} else if (property_name == "label") {
activatable$label <- action$label
}
}
## ...
}
))