Queries the type of the state of the named action within
@action_group.
If the action is stateful then this function returns the
#GVariantType of the state. All calls to
g_action_group_change_action_state() must give a #GVariant of this
type and g_action_group_get_action_state() will return a #GVariant
of the same type.
If the action is not stateful then this function will return %NULL.
In that case, g_action_group_get_action_state() will return %NULL
and you must not call g_action_group_change_action_state().
The state type of a particular action will never change but it is
possible for an action to be removed and for a new action to be added
with the same name but a different state type.
Queries the type of the state of the named action within @action_group.
If the action is stateful then this function returns the #GVariantType of the state. All calls to g_action_group_change_action_state() must give a #GVariant of this type and g_action_group_get_action_state() will return a #GVariant of the same type.
If the action is not stateful then this function will return %NULL. In that case, g_action_group_get_action_state() will return %NULL and you must not call g_action_group_change_action_state().
The state type of a particular action will never change but it is possible for an action to be removed and for a new action to be added with the same name but a different state type.