为什么我的"Data"."data“没有使用ChangeNotifierProvider在ChangeNotifier类中更新？

import 'package:flutter/foundation.dart';

class Data extends ChangeNotifier {
  String _data;

  String get data => _data;

  void updateData(String newData) {
    _data = newData;
    notifyListeners();
  }
}

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

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return ChangeNotifierProvider(
      create: (context) => Data(),
      child: MaterialApp(
        // 应用程序的其余部分
      ),
    );
  }
}

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

class MyWidget extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    Data data = Provider.of<Data>(context);

    return Text(data.data);
  }
}