index.dart

class DashboardScreen extends StatefulWidget {
  const DashboardScreen({super.key});

  @override
  State<DashboardScreen> createState() => _DashboardScreenState();
}

class _DashboardScreenState extends State<DashboardScreen>
    with SingleTickerProviderStateMixin {
  late TabController _tabController;

  int _activeTabIndex = 0;

  @override
  void initState() {
    super.initState();

    _tabController = TabController(length: 2, vsync: this);
    _tabController.addListener(_setActiveTabIndex);
  }

  void _setActiveTabIndex() {
    setState(() {
      _activeTabIndex = _tabController.index;
    });
  }

  @override
  void dispose() {
    _tabController.dispose();
    super.dispose();
  }

  

  @override
  Widget build(BuildContext context) {
    return PopScope(
      canPop: false,
      child: Scaffold(
        primary: false,
        body: SafeArea(
            child: Padding(
          padding: EdgeInsets.symmetric(vertical: 20.w, horizontal: 20.w),
          child: NestedScrollView(
              headerSliverBuilder: (context, innerBoxIsScrolled) => [
                    SliverPersistentHeader(
                      pinned: true,
                      floating: true,
                      delegate: _DashboardPersitentAppDelegate(
                        child: PreferredSize(
                          preferredSize: Size.fromHeight(kHeight(context) / 7),
                          child: DashboardHeader(
                              tabBar: Container(
                                height: 40.h,
                                padding: EdgeInsets.all(5.h),
                                decoration: BoxDecoration(
                                    color: Colors.grey.withOpacity(0.3),
                                    borderRadius: BorderRadius.circular(30.r)),
                                child: TabBar(
                                  controller: _tabController,
                                  tabs: const [
                                    Text('Discover'),
                                    Text('My Match')
                                  ],
                                  dividerColor: Colors.transparent,
                                  indicatorSize: TabBarIndicatorSize.tab,
                                  indicatorColor: Colors.transparent,
                                  indicator: BoxDecoration(
                                    gradient: Appcolors.tabBarGradient,
                                    borderRadius: BorderRadius.circular(30.r),
                                  ),
                                  unselectedLabelStyle: Theme.of(context)
                                      .textTheme
                                      .bodyMedium!
                                      .copyWith(
                                          fontSize: 16,
                                          fontWeight: FontWeight.w500),
                                  unselectedLabelColor: Appcolors.blackColor,
                                  labelColor: Appcolors.whiteColor,
                                  labelStyle: Theme.of(context)
                                      .textTheme
                                      .bodyMedium!
                                      .copyWith(
                                          fontSize: 16,
                                          fontWeight: FontWeight.w500),
                                ),
                              ),
                             ),
                        ),
                        childrenHeight: kHeight(context) / 7,
                      ),
                    )
                  ],
              body: TabBarView(
                controller: _tabController,
                children: const [],
              )),
        )),
      ),
    );
  }
}

class _DashboardPersitentAppDelegate extends SliverPersistentHeaderDelegate {
  _DashboardPersitentAppDelegate(
      {required this.child,
      required this.childrenHeight,
      double topSafeArea = 75})
      : _topSafeArea = topSafeArea;

  final double _topSafeArea;

  final double childrenHeight;
  final PreferredSize child;

  @override
  Widget build(
      BuildContext context, double shrinkOffset, bool overlapsContent) {
    return Container(
      decoration: const BoxDecoration(color: Appcolors.scaffoldbg),
      child: child,
    );
  }

  @override
  double get maxExtent => child.preferredSize.height + _topSafeArea;

  @override
  double get minExtent => child.preferredSize.height + _topSafeArea;

  // double get maxShrinkOffset => maxExtent - minExtent + _topSafeArea;
  @override
  bool shouldRebuild(covariant SliverPersistentHeaderDelegate oldDelegate) {
    return true;
  }
}