addIndexListener method
Adds a listener
callback for selection changes at a specific index
only.
Implementation
void addIndexListener(int index, ItemSelectionChangeCallback listener) {
assert(_debugAssertNotDisposed());
if (!_indexListeners!.containsKey(index)) {
_indexListeners![index] = ObserverList<ItemSelectionChangeCallback>();
}
_indexListeners![index]!.add(listener);
}