nested_tab_and_list.dart

import 'package:flutter/material.dart';

void main() => runApp(MyApp());

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Nested tab bar list demo',
      theme: ThemeData(
        primarySwatch: Colors.blue,
      ),
      home: MyHomePage(title: 'Flutter Demo Home Page'),
    );
  }
}

class MyHomePage extends StatefulWidget {
  MyHomePage({Key key, this.title}) : super(key: key);

  final String title;

  @override
  _MyHomePageState createState() => _MyHomePageState();
}

class _MyHomePageState extends State<MyHomePage> {
  final List<String> _tabs = ['Tab One', 'Tab Two'];

  @override
  Widget build(BuildContext context) {
    return Scaffold(
        body: DefaultTabController(
      length: _tabs.length,
      child: NestedScrollView(
        headerSliverBuilder: (BuildContext context, bool innerBoxIsScrolled) {
          return <Widget>[
            SliverOverlapAbsorber(
              handle: NestedScrollView.sliverOverlapAbsorberHandleFor(context),
              child: SliverAppBar(
                title: const Text('Junto Header...can be custom'),
                pinned: false,
                expandedHeight: 350.0,
                forceElevated: innerBoxIsScrolled,
                bottom: TabBar(
                  tabs: _tabs.map((String name) => Tab(text: name)).toList(),
                ),
              ),
            ),
          ];
        },
        body: TabBarView(
          // These are the contents of the tab views, below the tabs.
          children: _tabs.map((String name) {
            return SafeArea(
              top: false,
              bottom: false,
              child: Builder(
                builder: (BuildContext context) {
                  return CustomScrollView(
                    key: PageStorageKey<String>(name),
                    slivers: <Widget>[
                      SliverOverlapInjector(
                        handle: NestedScrollView.sliverOverlapAbsorberHandleFor(
                            context),
                      ),
                      SliverPadding(
                        padding: const EdgeInsets.all(8.0),
                        sliver: SliverList(
                          delegate: SliverChildBuilderDelegate(
                            (BuildContext context, int index) {
                              return Container(
                                height: 500.0,
                                color:
                                    index % 2 == 0 ? Colors.red : Colors.orange,
                              );
                            },
                            childCount: 50,
                          ),
                        ),
                      ),
                    ],
                  );
                },
              ),
            );
          }).toList(),
        ),
      ),
    ));
  }
}