the name of the action
the type of the parameter that will be passed to handlers for the #GSimpleAction::activate signal, or %NULL for no parameter
the initial state of the action
a new #GSimpleAction
ConstructionException GTK+ fails to create the object.
2.28
Creates a new stateful action.
All future state values must have the same #GVariantType as the initial @state.
If the @state #GVariant is floating, it is consumed.