registerOnChange method
Set the function to be called when the control receives a change event.
NOTE: This function should only be called by view (i.e. user-initiated) changes. Incorrect implementation of registerOnChange will cause issues such as the control incorrectly being marked as dirty from a model update.
Implementation
@override
void registerOnChange(callback) {
disposer.addStreamSubscription(_updateStream.listen((_) {
//if (input == null) return; // Input is no longer valid
final rawValue = input.inputText;
final value = parseNumber(rawValue);
// Pass the rawValue and the num value. This allows validators to process
// whichever one they would like.
callback(value, rawValue: rawValue);
}));
}