NestedScrollView Example

main.dart

import 'package:flutter/material.dart';

final Color darkBlue = Color.fromARGB(255, 18, 32, 47);

void main() {
  runApp(MyApp());
}

class MyApp extends StatefulWidget {
  @override
  _MyAppState createState() => _MyAppState();
}

class _MyAppState extends State<MyApp> with SingleTickerProviderStateMixin {
  TabController _tabController;
  @override
  void initState() {
    super.initState();
    _tabController = TabController(length: 2, vsync: this);
  }

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
        theme: ThemeData.dark().copyWith(scaffoldBackgroundColor: darkBlue),
        debugShowCheckedModeBanner: false,
        home: Scaffold(
          body: NestedScrollView(
          headerSliverBuilder: (c, i) => [
            SliverOverlapAbsorber(
            handle: NestedScrollView.sliverOverlapAbsorberHandleFor(c),
            sliver: SliverAppBar(
              pinned: true,
              backgroundColor: Colors.black,
              expandedHeight: 250,
              flexibleSpace: Column(
                children: [
                  Expanded(
                    flex: 1,
                    child: Container(
                      child: Center(child: Text('Some Title')),
                      color: Colors.black,
                    ),
                  ),
                  Expanded(
                    flex: 5,
                    child: Container(
                      color: Colors.red,
                      child: Row(
                        mainAxisAlignment: MainAxisAlignment.spaceEvenly,
                        children: [
                          Center(child: Text("SomeContainer")),
                          Center(child: Text("SomeContainer2")),
                        ]
                      )
                    ),
                  ),
                ],
              ),
              bottom: TabBar(
                labelColor: Colors.black,
                indicatorSize: TabBarIndicatorSize.label,
                controller: _tabController,
                tabs: <Widget>[
                  Tab(text: "Tab1"),
                  Tab(text: "Tab2"),
                ],
              ),
            ),
          ),
        ], // outer
        body: TabBarView(
          controller: _tabController,
          children: <Widget>[
            Builder(
              builder: (c) => CustomScrollView(
                slivers: [
                  SliverOverlapInjector(handle: NestedScrollView.sliverOverlapAbsorberHandleFor(c)),
                  SliverFillRemaining(
                    child: Container(
                      color: Colors.green,
                      child: Center(child: Text("SomeTextView")),
                    ),
                  ),
                ],
              ),
            ),
            Builder(
              builder: (c) => CustomScrollView(
                slivers: [
                  SliverOverlapInjector(handle: NestedScrollView.sliverOverlapAbsorberHandleFor(c)),
                  SliverPadding(
                    padding: const EdgeInsets.all(15.0),
                    sliver: SliverFixedExtentList(
                      itemExtent: 50.0,
                      delegate: SliverChildBuilderDelegate(
                        (c, i) => Container(child: Text('list item $i')),
                      ),
                    ),
                  ),
                ],
              ),
            ),
          ],
        ),
      ),
     )
   );
  }
}