Simple Provider Flutter Example

flutter.dart

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

void main() {
  runApp(
    ChangeNotifierProvider(
      create: (_) => Person(name: "Yohan", age: 25),
      child: MyApp(),
    ),
  );
}

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

  @override
  State<MyApp> createState() => _MyAppState();
}

class _MyAppState extends State<MyApp> {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      home: MyBody(),
    );
  }
}

class MyBody extends StatefulWidget {
  const MyBody({Key? key}) : super(key: key);

  @override
  State<MyBody> createState() => _MyBodyState();
}

class _MyBodyState extends State<MyBody> {
  @override
  Widget build(BuildContext context) {
    return Scaffold(
        body: SafeArea(
            child: Column(
      children: [
        Center(
          child: Consumer<Person>(
            builder: (context, value, child) {
              return Text(value.name);
            },
          ),
        ),
        ElevatedButton(
          child: Text('Change'),
          onPressed: () {
            Provider.of<Person>(context, listen: false).Change();
          },
        )
      ],
    )));
  }
}

class Person extends ChangeNotifier {
  var name = "test";

  Person({name, age}) {
    this.name = name;
  }

  void Change() {
    this.name = 'Mahmoud';
    notifyListeners();
  }
}