当我向listview添加元素时，如何在Flutter中更新listview？

import 'package:flutter/material.dart';

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

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

class _MyAppState extends State<MyApp> {
  List<String> items = ['Item 1', 'Item 2', 'Item 3'];

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      home: Scaffold(
        appBar: AppBar(
          title: Text('ListView Example'),
        ),
        body: ListView.builder(
          itemCount: items.length,
          itemBuilder: (BuildContext context, int index) {
            return ListTile(
              title: Text(items[index]),
            );
          },
        ),
        floatingActionButton: FloatingActionButton(
          child: Icon(Icons.add),
          onPressed: () {
            setState(() {
              items.add('New Item');
            });
          },
        ),
      ),
    );
  }
}