Flutter -使用仅提供程序包的状态管理-如何在不同的提供程序类之间共享用户数据

import 'package:flutter/foundation.dart';

class UserData extends ChangeNotifier {
  String username;
  int age;

  void updateUserData(String name, int userAge) {
    username = name;
    age = userAge;
    notifyListeners();
  }
}

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

void main() {
  runApp(
    ChangeNotifierProvider(
      create: (context) => UserData(),
      child: MyApp(),
    ),
  );
}

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      home: MyHomePage(),
    );
  }
}

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

class MyHomePage extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    final userData = Provider.of<UserData>(context);

    return Scaffold(
      appBar: AppBar(
        title: Text('My App'),
      ),
      body: Center(
        child: Column(
          mainAxisAlignment: MainAxisAlignment.center,
          children: <Widget>[
            Text('Username: ${userData.username}'),
            Text('Age: ${userData.age}'),
          ],
        ),
      ),
    );
  }
}