import 'package:flutter/material.dart';

void main() {
  runApp(const TestApp());
}

class TestApp extends StatelessWidget {
  const TestApp({ super.key });

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      theme: ThemeData(
        colorScheme: ColorScheme.fromSeed(seedColor: Colors.blue),
        useMaterial3: true,
      ),
      home: Scaffold(
        body: 
        NestedScrollView(
          headerSliverBuilder: (context, innerBoxIsScrolled) {
            return [
            SliverOverlapAbsorber(
              handle: NestedScrollView.sliverOverlapAbsorberHandleFor(context),
              sliver: 
              SliverAppBar.large(
                title: const Text('Example App'),
                forceElevated: innerBoxIsScrolled,
              ),
            ),
          ];},
          body: Builder(
            builder: (context) {
              // Builder required to obtain correct BuildContext.
              return CustomScrollView(
                slivers: [
                 SliverOverlapInjector(
                   handle: NestedScrollView.sliverOverlapAbsorberHandleFor(
                     context,
                   ),
                 ),
                  SliverList(
                    delegate: SliverChildBuilderDelegate(
                      (context, index) {
                        return ListTile(
                          title: Text('Item ${index.toString()}'),
                        );
                      },
                      childCount: 50,
                    ),
                  )
                ],
              );
            },
          ),
        ),
      ),
    );
  }
}