WidgetA

import ...

class FeedPage extends StatefulWidget {
  @override
  _FeedPageState createState() => _FeedPageState();
}

class _FeedPageState extends State<FeedPage> {
  var itemSelected = 0;

  final ScrollController controller = ScrollController();

  @override
  Widget build(BuildContext context) {
    FeedProvider _feedProvider = Provider.of<FeedProvider>(context);
    return SafeArea(
      child: Container(
        foregroundDecoration:
            BoxDecoration(color: Color(...)),
        child: Column(
          children: <Widget>[
            buildHead(),
            buildFilterOptionsFeed(),
            buildListView(_feedProvider)
          ],
        ),
      ),
    );
  }


  Widget buildListView(provider) {
    return Expanded(
      child: ListView.builder(
        controller: controller,
        itemCount: provider.getItens().length,
        itemBuilder: (context, index) {
          var feed = provider.getItens();
          var post = feed[index];
          // passando os dados para o Widget CardView
          return feedCardView(context, post);
        },
      ),
    );
  }

  void moveTop() {
    try {
      controller.animateTo(0,
          duration: Duration(microseconds: 50), curve: Curves.easeInBack);
    } catch (e) {}
  }

}