State Management in Flutter using Provider(5.0.0) Package

main.dart

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

void main() async{
  WidgetsFlutterBinding.ensureInitialized();
  runApp(
      ChangeNotifierProvider(
        create: (context) => Counter(),
        child: MyApp(),),
    );
}

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Flutter Demo',
      theme: ThemeData(
        primarySwatch: Colors.blue,
      ),
      home: MyHomePage(title: 'Flutter Demo Home Page'),
    );
  }
}

class MyHomePage extends StatefulWidget {
  MyHomePage({Key? key, required this.title}) : super(key: key);
  final String title;

  @override
  _MyHomePageState createState() => _MyHomePageState();
}

class _MyHomePageState extends State<MyHomePage> {
  @override
  Widget build(BuildContext context) {
    Counter counter = Provider.of<Counter>(context,listen: false);
    return Scaffold(
      appBar: AppBar(
        title: Text(widget.title),
      ),
      body: Center(
        child: Column(
          mainAxisAlignment: MainAxisAlignment.center,
          children: <Widget>[
            Text(
              'You have pushed the button this many times:',
            ),
            Text(
              '${Provider.of<Counter>(context).getCount}',
              style: Theme.of(context).textTheme.headline4,
            ),
          ],
        ),
      ),
      floatingActionButton: FloatingActionButton(
        onPressed: counter.incrementCounter,
        tooltip: 'Increment',
        child: Icon(Icons.add),
      ),
    );
  }
}

class Counter extends ChangeNotifier{
  int _counter = 0;
  int get getCount => _counter;
  void incrementCounter(){
    _counter++;
    notifyListeners();
  }
}