scrollBy method

@override bool scrollBy(int delta)

Scrolls by a delta. Returns true if the offset changed.

Implementation

@override
bool scrollBy(int delta) {
  if (delta == 0) return false;
  final next = delta > 0 ? _model.scrollDown(delta) : _model.scrollUp(-delta);
  if (identical(next, _model)) return false;
  _model = next;
  _notifyListeners();
  return true;
}