ChangeNotifier -如何动态更新或重建构造函数列表？

import 'package:flutter/foundation.dart';

class MyModel extends ChangeNotifier {
  List<String> _items = [];

  List<String> get items => _items;

  void addItem(String item) {
    _items.add(item);
    notifyListeners();
  }
}

class MyWidget extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return ChangeNotifierProvider(
      create: (context) => MyModel(),
      child: Consumer<MyModel>(
        builder: (context, model, child) {
          return ListView.builder(
            itemCount: model.items.length,
            itemBuilder: (context, index) {
              return ListTile(
                title: Text(model.items[index]),
              );
            },
          );
        },
      ),
    );
  }
}