activateNext method
void
activateNext()
Activates next element in the list, if the active item is not already the last item.
Implementation
void activateNext() {
if (_items.isEmpty) {
_activeIndex = -1;
} else if (_activeIndex < _items.length - 1) {
_activeIndex++;
} else if (_loop) {
_activeIndex = 0;
}
_modelChanged.add(null);
}