Flutter Riverpod

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Flutter Riverpod

link

• https://pub.dev/packages/flutter_riverpod

基本

• はじめに
• flutter_riverpod

データの受け渡し

---

Providerをグローバルに定義し、データを受け渡す

データを渡す

---

種類	目的
Provider	任意のデータを渡す
FutureProvider	Futureから取得する任意のデータを渡す
Stream Provider	Streamから取得する任意のデータを渡す
StateProvider	変更可能な任意のデータを渡す
StateNotifireProvider	StateNotifireProviderから取得する任意のデータを渡す
ScopedProvider	場所に応じて異なる任意のデータを渡す

データを受け取る

---

種類	目的
ConsumerWidget	継承することでデータを受け取れるWidget
Consumer	コールバック内でデータを受け取れるWidget
useProvider()	flutter_hooksを利用し、HookWidgetを継承したWidgetでデータを受け取れる関数
context.read()	BuildContextからデータを受け取れる関数(ただしデータの変更通知は受け取れない)
ProviderContainer	Flutterに依存しない形でデータを受け取れる

基本

---

FlutterFire

pubspec.yaml=

  flutter:
    sdk: flutter
  flutter_riverpod: ^0.14.0+3
  firebase_core: ^1.7.0
  firebase_auth: ^3.1.3
  json_annotation: ^4.0.1

dev_dependencies:
  flutter_test:
    sdk: flutter
  json_serializable: ^4.1.3
  build_runner: ^2.1.1

Main

• main.dart

import 'package:firebase_core/firebase_core.dart';
import 'package:flutter_riverpod/flutter_riverpod.dart';
import 'package:flutter/material.dart';
import 'package:repbuilder/provider/providers.dart';
import 'package:repbuilder/widget/widgets.dart';
import 'package:repbuilder/screen/sign_in/sigin_in.dart';
import 'package:repbuilder/screen/person_list/person_list.dart';

void main() async {
  // Flutter の初期化処理を待つ
  WidgetsFlutterBinding.ensureInitialized();
  // Firebaseの初期化(非同期)を待つ
  await Firebase.initializeApp();
  
  runApp(ProviderScope(child: RepBuilder()));
}

class RepBuilder extends StatelessWidget {
  // This widget is the root of your application.
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Report Builder',
      theme: ThemeData(
        primarySwatch: Colors.blue,
      ),
      home: Consumer(
        builder: (context,  watch, child) { 
          final user = watch(userProvider);
          return user.when(
            data: (user) => (user == null) ? SignInScreen() : PersonLIst(), 
            loading: () => loadingWidget(), 
            error: (e, stackTrace) => errorWidget(context, e, stackTrace),
          );
        },
      )
    );
  }
}

Model

import 'package:json_annotation/json_annotation.dart';
part 'person.g.dart';

@JsonSerializable()
class Person {
  String? id;
  String? name;
  DateTime? createdAt;

  Person({this.id, this.name});

  factory Person.fromJson(Map<String, dynamic> json) => _$PersonFromJson(json);
  Map<String, dynamic> toJson() => _$PersonToJson(this);
}

• json_annotation

$ flutter pub run build_runner build

Repository

import 'package:firebase_auth/firebase_auth.dart';
import 'package:repbuilder/model/person.dart';

class PersonRepository {
  final User user;
  PersonRepository(this.user);

  List<Person> getPersonList() {
    // DUMMY 
    return new List.of([new Person(id:"id1",name:this.user.email), new Person(id:"id2",name:this.user.email)]);
  }
}

Provider

import 'package:firebase_auth/firebase_auth.dart';
import 'package:flutter_riverpod/flutter_riverpod.dart';
import 'package:repbuilder/repository/repositories.dart';

final userProvider = StreamProvider.autoDispose((ref) {
  return FirebaseAuth.instance.authStateChanges();
});

final personRepositoryProvider = Provider.autoDispose((ref) {
  final User? user = ref.watch(userProvider).data?.value;
  return user == null ? null : PersonRepository(user);
});

Consumer

import 'package:flutter/material.dart';
import 'package:repbuilder/provider/providers.dart';
import 'package:flutter_riverpod/flutter_riverpod.dart';

class PersonLIst extends StatefulWidget {
  @override
  _PersonLIstState createState() => _PersonLIstState();
}

class _PersonLIstState extends State<PersonLIst> {
  @override
  Widget build(BuildContext context) {
    return Consumer(
      builder: (context, watch, child) {
        final personRep = watch(personRepositoryProvider);
        var persons = personRep?.getPersonList();
        return Text(persons?.elementAt(0).name ?? 'null'); 
      },
    );
  }
}