如何从Flutter中的页面更新主类widget

dependencies:
  flutter:
    sdk: flutter
  provider: ^6.0.1

import 'package:flutter/material.dart';

class CounterProvider with ChangeNotifier {
  int _counter = 0;

  int get counter => _counter;

  void incrementCounter() {
    _counter++;
    notifyListeners();
  }
}

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

class MainPage extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text('Flutter Demo'),
      ),
      body: Center(
        child: Column(
          mainAxisAlignment: MainAxisAlignment.center,
          children: <Widget>[
            Text(
              'Counter:',
            ),
            Consumer<CounterProvider>(
              builder: (context, counterProvider, child) {
                return Text(
                  '${counterProvider.counter}',
                  style: Theme.of(context).textTheme.headline4,
                );
              },
            ),
          ],
        ),
      ),
      floatingActionButton: FloatingActionButton(
        onPressed: () {
          Provider.of<CounterProvider>(context, listen: false)
              .incrementCounter();
        },
        child: Icon(Icons.add),
      ),
    );
  }
}

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

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

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return ChangeNotifierProvider(
      create: (context) => CounterProvider(),
      child: MaterialApp(
        title: 'Flutter Demo',
        theme: ThemeData(
          primarySwatch: Colors.blue,
        ),
        home: MainPage(),
      ),
    );
  }
}