Animated footer using Flutter Web

animated_footer.dart

import 'package:flutter/material.dart';

class ScrollControllerProvider extends ChangeNotifier {
  ScrollController scrollController = ScrollController();
  double footerWidth = 1000.0;

  ScrollControllerProvider(context) {
    scrollController.addListener(() {
      if (scrollController.position.pixels >=
          scrollController.position.maxScrollExtent - 50) {
        footerWidth = MediaQuery.of(context).size.width;
        notifyListeners();
      } else {
        footerWidth = 1000.0;
        notifyListeners();
      }
    });
  }
  @override
  void dispose() {
    scrollController.dispose();
    super.dispose();
  }
}