Flutter:如何将数据添加到列表中？

import 'package:flutter/material.dart';

class ListItem {
  String title;
  String subtitle;

  ListItem(this.title, this.subtitle);
}

class MyListPage extends StatefulWidget {
  @override
  _MyListPageState createState() => _MyListPageState();
}

class _MyListPageState extends State<MyListPage> {
  List<ListItem> items = [];

  void addItem() {
    setState(() {
      items.add(ListItem('Title', 'Subtitle'));
    });
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text('My List'),
      ),
      body: ListView.builder(
        itemCount: items.length,
        itemBuilder: (context, index) {
          return ListTile(
            title: Text(items[index].title),
            subtitle: Text(items[index].subtitle),
          );
        },
      ),
      floatingActionButton: FloatingActionButton(
        onPressed: addItem,
        child: Icon(Icons.add),
      ),
    );
  }
}

void main() {
  runApp(MaterialApp(
    home: MyListPage(),
  ));
}