Counter app with provider

main.dart

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

// counter.dart

class CountNotifier extends ChangeNotifier {
  int count = 0;

  void increment() {
    count += 1;
    notifyListeners();
  }
}

// main.dart

void main() {
  runApp(ChangeNotifierProvider(
      create: (_) => CountNotifier(), child: const MyApp()));
}

class MyApp extends StatelessWidget {
  const MyApp({Key? key}) : super(key: key);

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      home: Scaffold(
        appBar: AppBar(title: const Text('Counter example')),
        body: Center(
          child: Text('${Provider.of<CountNotifier>(context).count}'),
        ),
        floatingActionButton: FloatingActionButton(
          onPressed: () =>
              Provider.of<CountNotifier>(context, listen: false).increment(),
          child: const Icon(Icons.add),
        ),
      ),
    );
  }
}