flutter_riverpod: ^2.5.1

import 'package:flutter_riverpod/flutter_riverpod.dart';

class Todo {
  bool isCompleted;
  String description;

  Todo(this.isCompleted, this.description);
}

final todoProvider = StateProvider<Todo>((ref) {
  return Todo(true, "공부하기");
});

import 'package:flutter/material.dart';
import 'package:flutter_riverpod/flutter_riverpod.dart';
import 'package:stateapp/todo.dart';

void main() {
  runApp(ProviderScope(child: MyApp()));
}

class MyApp extends StatelessWidget {
  MyApp({super.key});

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      home: HomePage(),
    );
  }
}

class HomePage extends ConsumerWidget {
  HomePage({super.key});

  @override
  Widget build(BuildContext context, WidgetRef ref) {

    Todo todo = ref.read(todoProvider);

    return Scaffold(
      body: Center(
        child: Column(
          mainAxisAlignment: MainAxisAlignment.center,
          children: [
            Text(
              "완료 : ${todo.isCompleted.toString()}, 내용 : ${todo.description}",
              style: TextStyle(fontSize: 30),
            ),
            ElevatedButton(onPressed: (){
              ref.read(todoProvider).isCompleted = false;
            }, child: Text("공부완료")),
            Deps1(),
          ],
        ),
      ),
    );
  }
}

class Deps1 extends StatelessWidget {
  const Deps1({
    super.key,
  });

  @override
  Widget build(BuildContext context) {
    return Deps2();
  }
}

class Deps2 extends StatelessWidget {
  const Deps2({
    super.key,
  });

  @override
  Widget build(BuildContext context) {
    return Deps3();
  }
}

class Deps3 extends ConsumerWidget {
  const Deps3({
    super.key,
  });

  @override
  Widget build(BuildContext context, WidgetRef ref) {

    Todo todo = ref.read(todoProvider);

    return Text("Deps3 컨텍스트 : ${todo.isCompleted}", style: TextStyle(color: Colors.red, fontSize: 30),);
  }
}