nested_scroll_with_header.dart

import 'package:flutter/material.dart';

class TestPage2 extends StatefulWidget {

  @override
  _TestPageState2 createState() => new _TestPageState2();
}

class _TestPageState2 extends State<TestPage2> {

  @override
  Widget build(BuildContext context) {
    return new DefaultTabController(
      length: 2,
      child: new Scaffold(
        body: new NestedScrollView(
          headerSliverBuilder: (BuildContext context, bool innerBoxIsScrolled) {
            return [
              new SliverAppBar(
                backgroundColor: Colors.black26,
                title: new Text('Here title'),
                pinned: true,
                floating: true,
                bottom: new TabBar(
                    tabs: [
                      new Tab(text: 'Tab1'),
                      new Tab(text: 'Tab2'),
                    ]
                ),
              ),
            ];
          },
          body: new Stack(
            children: <Widget>[
              new Positioned(
                top: 0.0,
                left: 0.0,
                right: 0.0,
                child: new Material(
                  elevation: 4.0,
                  color: Colors.white,
                  child: new Container(
                    height: 48.0,
                    child: new Center(
                        child: const Text('Here my fixed header')),
                  ),
                ),
              ),
              new Positioned(
                top: 48.0,
                left: 0.0,
                right: 0.0,
                bottom: 0.0,
                child: new RefreshIndicator(
                    onRefresh: () {},
                    child: new ListView.builder(
                      itemBuilder: _buildItem,
                      itemCount: 30,
                    )
                ),
              ),
            ],
          ),
        ),
      ),
    );
  }

  Widget _buildItem(BuildContext context, int index) {
    return new ListTile(
      title: new Text('Title $index'),
      subtitle: new Text('Subtitle $index'),
    );
  }
}