addValueListener method
Implementation
void addValueListener(ValueChanged<T> listener) {
if (!_valueListeners.containsKey(listener)) {
_valueListeners[listener] = () => listener(value);
addListener(_valueListeners[listener]!);
}
}
void addValueListener(ValueChanged<T> listener) {
if (!_valueListeners.containsKey(listener)) {
_valueListeners[listener] = () => listener(value);
addListener(_valueListeners[listener]!);
}
}