performRebuild method

  1. @override
void performRebuild ()
override

Called by rebuild() after the appropriate checks have been made.

Implementation 

@override
void performRebuild() {
  _childWidgets.clear();
  super.performRebuild();
  if (_childElements.isEmpty)
    return;

  final int firstIndex = _childElements.firstKey();
  final int lastIndex = _childElements.lastKey();

  for (int index = firstIndex; index <= lastIndex; ++index) {
    final Element newChild = updateChild(_childElements[index], retrieveWidget(index), index);
    if (newChild != null) {
      _childElements[index] = newChild;
    } else {
      _childElements.remove(index);
    }
  }
}