main.dart

import 'package:flutter/material.dart';

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

class TabBarDemo extends StatefulWidget {
  @override
  _TabBarDemoState createState() => _TabBarDemoState();
}

class _TabBarDemoState extends State<TabBarDemo> {
  final strings1 = List<String>.generate(10000, (i) => "Tab 1, Item $i");
  final strings2 = List<String>.generate(10000, (i) => "Tab 2, Item $i");

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      home: DefaultTabController(
        length: 2,
        child: Scaffold(
          appBar: AppBar(
            bottom: TabBar(
              tabs: [
                Tab(icon: Icon(Icons.directions_car)),
                Tab(icon: Icon(Icons.directions_transit)),
              ],
            ),
            title: Text('Tabs Demo'),
          ),
          body: TabBarView(
            children: [
              MyList(
                items: strings1,
                key: PageStorageKey('list1'),
              ),
              MyList(
                items: strings2,
                key: PageStorageKey('list2'),
              ),
            ],
          ),
        ),
      ),
    );
  }
}

class MyList extends StatelessWidget {
  final List<String> items;

  MyList({Key key, @required this.items})
      : super(key: key);

  @override
  Widget build(BuildContext context) {
    return ListView.builder(
      itemCount: items.length,
      itemBuilder: (context, index) {
        return ListTile(
          title: Text('${items[index]}'),
        );
      },
    );
  }
}