How to use google Navbar with Riverpod?

I'm using flutter-riverpod for state management in my app. Since for using Riverpod, I have to change my Stateful widget into a consumer widget, I couldn't access setState(). Now, after writing state management code for bottom bar using Riverpod, it does not work.

Here is my code-

int index = 0;

class HomePage extends ConsumerWidget {
  final currentIndex = Provider<int>((ref) => index);

  Widget build(BuildContext context, ScopedReader watch) {
    int _currentIndex = watch(currentIndex);

    

    return auth.when(//authstatchange provider
      data: (e) {
        if (e!=null&&e.uid != null) {
          return Scaffold(
            body: PageView(
              physics: NeverScrollableScrollPhysics(),
              controller: _pageController,
              onPageChanged: (ind) {
                index = ind;
              },
              children: [
                SomePage(),
              ],
            ),
            bottomNavigationBar: SingleChildScrollView(
              scrollDirection: Axis.horizontal,
              child: Container(
                someCode(),
),
                child: SomeCode(),)
                        tabBackgroundColor: Colors.grey[800],
                        tabs: [
                          tabs()
                        ],
                        selectedIndex: _currentIndex,
                        onTabChange: (ind) {
                          index = ind;
                         _pageController.jumpToPage(index);
                        )//closing brackets (omitted)
   //brackets