ListView Performace

main.dart

import 'package:flutter/foundation.dart';
import 'package:flutter/material.dart';

void main() {
  runApp(MyApp(
      itemsA: List<String>.generate(250, (i) => "Item $i"),
      itemsB: List<String>.generate(250, (i) => "Item $i")));
}

class MyApp extends StatefulWidget {
  final List<String> itemsA;
  final List<String> itemsB;

  MyApp({Key key, @required this.itemsA, this.itemsB}) : super(key: key);

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

class MyAppState extends State<MyApp> with SingleTickerProviderStateMixin {
  TabController _tabController;

  final Key listKeyA = PageStorageKey('listA');
  final Key listKeyB = PageStorageKey('listB');


  @override
  void initState() {
    super.initState();
    _tabController = TabController(vsync: this, length: 2);
  }

  @override
  Widget build(BuildContext context) {
    final title = 'Long List';

    return MaterialApp(
        title: title,
        home: Scaffold(
          appBar: AppBar(
            title: Text(title),
          ),
          body: TabBarView(controller: _tabController, children: [
            ListWidget(key: listKeyA, items: widget.itemsA),
            ListWidget(key: listKeyB, items: widget.itemsB),
          ]),
          bottomNavigationBar: Container(
            color: Colors.blue,
            child: TabBar(
              controller: _tabController,
              indicatorColor: Colors.white,
              tabs: <Widget>[Tab(text: "ListA"), Tab(text: "ListB")],
            ),
          ),
        ));
  }
}

class ListWidget extends StatefulWidget {
  final List<String> items;

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

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

class ListWidgetState extends State<ListWidget> {
  @override
  Widget build(BuildContext context) {
    return ListView.builder(
      itemCount: widget.items.length,
      itemBuilder: (context, index) {
        return ListTile(
          title: Text('${widget.items[index]}'),
        );
      },
    );
  }
}