Flutter adding Draggable Scrollbar to a CustomScrollView? It keeps giving me 'The argument type CustomScrollView can't be assigned to BoxScrollView'

Question

A Simple example would be:

Scaffold(
          floatingActionButton: _fab(),
          floatingActionButtonLocation: _fabLocation(),
          body: Scrollbar(
            child: CustomScrollView(
              slivers: <Widget>[
                SliverAppBar(
                  automaticallyImplyLeading: false,
                  leading: null,
                  backgroundColor: Theme.of(context).colorScheme.secondary,
                  title: AutoSizeText(
                    _catalogSearchRatio,
                    style: Theme.of(context).textTheme.title.copyWith(
                        color: Theme.of(context).colorScheme.onSecondary),
                  ),
                  floating: true,
                  pinned: false,
                ),
                SliverFixedExtentList(
                  itemExtent: 90.0,
                  delegate: SliverChildBuilderDelegate((context, index) {
                    return Padding(
                      padding: const EdgeInsets.symmetric(
                          horizontal: 5.0, vertical: 5.0),
                      child: CatalogItems.medidaGroups
                              .contains(_itemsCatalogDisplay[index].group)
                          ? _medidasCard(
                              index, _itemsCatalogDisplay, _catalogSearchQuery)
                          : _catalogCard(index, _itemsCatalogDisplay,
                              _catalogSearchQuery, _cartItems, _filteredGroups),
                    );
                  }, childCount: itemsCatalogDisplayLength),
                ),
              ],
              controller: _catalogScrollController,
            ),
          ),
        );

In the above example, a Scrollbar can be used and that's fine. BUT you can't drag the scrollbar. So I am using a package called draggable_scrollbar which lets me drag the scrollbar. However, I can't seem to replace the scrollbar I have in the example because it gives me the can't be assigned to BoxScrollView error. It works if it's just a Listview or a Listview.builder or even a GridView

Answer 1

Start by importing the Cupertino package like below..

Import 'package: flutter/cupertino.dart';

Now, inside your class which contains your ScrollViews add the ScrollController like below...

final ScrollController myScrollWorks = ScrollController();

Now wrap any of your ScrollViews... which in your case is a CustomScrollView with the code below

body: PrimaryScrollController(
    controller: myScrollWorks,
        child: CupertinoScrollbar(
            child: CustomScrollView(
                slivers:[
                    your slivers code here
                 ];