Riverpod Example

main.dart

import 'package:flutter/material.dart';
import 'package:flutter_riverpod/flutter_riverpod.dart';
import "dart:math";

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

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

  @override
  Widget build(BuildContext context, WidgetRef ref) {
    //:::
    final person = ref.watch(providerPerson);
    final notifier = ref.read(providerPerson.notifier);
    //:::
    return MaterialApp(
      title: 'Riverpod Demo',
      home: Scaffold(
        appBar: AppBar(
          title: const Text('Riverpod'),
        ),
        body: Center(
          child: Column(
            mainAxisAlignment: MainAxisAlignment.center,
            children: [
              TextButton(
                onPressed: () {
                  notifier.addStar();
                },
                child: const Text('Add Star'),
              ),
              Text(
                '⭐️ ${person.stars}',
              ),
              const Divider(),
              TextButton(
                onPressed: () {
                  notifier.addPet();
                },
                child: const Text('Add Pet'),
              ),
              for (var pet in person.pets) Text(pet)
            ],
          ),
        ),
      ),
    );
  }
}

class Person {
  final int stars;
  final List<String> pets;

  Person({
    this.stars = 0,
    this.pets = const [],
  });

  Person copyWith({int? stars, List<String>? pets}) {
    return Person(
      stars: stars ?? this.stars,
      pets: pets ?? this.pets,
    );
  }
}

final providerPerson = StateNotifierProvider<PersonState, Person>((ref) {
  return PersonState();
});

class PersonState extends StateNotifier<Person> {
  PersonState() : super(Person());

  addStar() {
    state = state.copyWith(stars: state.stars + 1);
  }

  addPet() {
    var list = ['cat', 'dog', 'hamster', 'fish', 'bird'];

    //Get random list element
    final random = Random();
    var pet = list[random.nextInt(list.length)];

    state = state.copyWith(pets: [...state.pets, pet]);
  }
}