在小部件中初始化StateProvider

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

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

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return ChangeNotifierProvider(
      create: (context) => StateProvider(),
      child: MaterialApp(
        title: 'State Provider Example',
        home: HomeScreen(),
      ),
    );
  }
}

class StateProvider with ChangeNotifier {
  // 在这里定义和管理应用程序的状态
  // 例如：String、int、bool等

  // 示例状态
  String _message = 'Hello World';

  String get message => _message;

  void updateMessage(String newMessage) {
    _message = newMessage;
    notifyListeners();
  }
}

class HomeScreen extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    final stateProvider = Provider.of<StateProvider>(context);

    return Scaffold(
      appBar: AppBar(
        title: Text('State Provider Example'),
      ),
      body: Center(
        child: Column(
          mainAxisAlignment: MainAxisAlignment.center,
          children: [
            Text(
              stateProvider.message,
              style: TextStyle(fontSize: 24),
            ),
            RaisedButton(
              onPressed: () {
                stateProvider.updateMessage('New Message');
              },
              child: Text('Update Message'),
            ),
          ],
        ),
      ),
    );
  }
}