🍑
familyとrecordは一緒に使えるらしい？
Overview
riverpodのfamilyとDart3のrecordは組み合わせることができるらしい？
Records
K9iさんの記事
簡単なものしか思いつかなかったのでとりあえず作ってみた。
summary
riverpodのfamilyは、パラメーターを渡すだけのようだ。。。
多分そうだと思う。とりあえずやってみよう!
import 'package:riverpod_annotation/riverpod_annotation.dart';
part 'fruit.g.dart';
// 果物の種類をenumで定義
enum Fruit {
apple,
banana,
orange,
}
// generatorを使わない場合
// final fruitProvider = Provider.family<String, Fruit>((ref, fruit) {
// var record = ('🍎', '🍌', '🍊');
// return switch (fruit) {
// Fruit.apple => record.$1,
// Fruit.banana => record.$2,
// Fruit.orange => record.$3,
// };
// });
// generatorを使う場合は、ref, の後に引数を渡すと、familyになるらしい？
String fruits(FruitsRef ref, Fruit fruit) {
// Dart3のrecordを使って、複数の値を返す。
var record = ('🍎', '🍌', '🍊');
// switchで、enumの値によって、返す値を変える。名前付きではないので、$1, $2, $3となる。
return switch (ref.fruit) {
Fruit.apple => record.$1,
Fruit.banana => record.$2,
Fruit.orange => record.$3,
};
}
自動生成するコマンドを実行する
flutter pub run build_runner watch --delete-conflicting-outputs
🤖こちらが自動生成されたコード
// GENERATED CODE - DO NOT MODIFY BY HAND
part of 'fruit.dart';
// **************************************************************************
// RiverpodGenerator
// **************************************************************************
String _$fruitsHash() => r'516a4a384f0de87f6871349b09ef783284b88dff';
/// Copied from Dart SDK
class _SystemHash {
_SystemHash._();
static int combine(int hash, int value) {
// ignore: parameter_assignments
hash = 0x1fffffff & (hash + value);
// ignore: parameter_assignments
hash = 0x1fffffff & (hash + ((0x0007ffff & hash) << 10));
return hash ^ (hash >> 6);
}
static int finish(int hash) {
// ignore: parameter_assignments
hash = 0x1fffffff & (hash + ((0x03ffffff & hash) << 3));
// ignore: parameter_assignments
hash = hash ^ (hash >> 11);
return 0x1fffffff & (hash + ((0x00003fff & hash) << 15));
}
}
/// See also [fruits].
(fruits)
const fruitsProvider = FruitsFamily();
/// See also [fruits].
class FruitsFamily extends Family<String> {
/// See also [fruits].
const FruitsFamily();
/// See also [fruits].
FruitsProvider call(
Fruit fruit,
) {
return FruitsProvider(
fruit,
);
}
FruitsProvider getProviderOverride(
covariant FruitsProvider provider,
) {
return call(
provider.fruit,
);
}
static const Iterable<ProviderOrFamily>? _dependencies = null;
Iterable<ProviderOrFamily>? get dependencies => _dependencies;
static const Iterable<ProviderOrFamily>? _allTransitiveDependencies = null;
Iterable<ProviderOrFamily>? get allTransitiveDependencies =>
_allTransitiveDependencies;
String? get name => r'fruitsProvider';
}
/// See also [fruits].
class FruitsProvider extends AutoDisposeProvider<String> {
/// See also [fruits].
FruitsProvider(
Fruit fruit,
) : this._internal(
(ref) => fruits(
ref as FruitsRef,
fruit,
),
from: fruitsProvider,
name: r'fruitsProvider',
debugGetCreateSourceHash:
const bool.fromEnvironment('dart.vm.product')
? null
: _$fruitsHash,
dependencies: FruitsFamily._dependencies,
allTransitiveDependencies: FruitsFamily._allTransitiveDependencies,
fruit: fruit,
);
FruitsProvider._internal(
super._createNotifier, {
required super.name,
required super.dependencies,
required super.allTransitiveDependencies,
required super.debugGetCreateSourceHash,
required super.from,
required this.fruit,
}) : super.internal();
final Fruit fruit;
Override overrideWith(
String Function(FruitsRef provider) create,
) {
return ProviderOverride(
origin: this,
override: FruitsProvider._internal(
(ref) => create(ref as FruitsRef),
from: from,
name: null,
dependencies: null,
allTransitiveDependencies: null,
debugGetCreateSourceHash: null,
fruit: fruit,
),
);
}
AutoDisposeProviderElement<String> createElement() {
return _FruitsProviderElement(this);
}
bool operator ==(Object other) {
return other is FruitsProvider && other.fruit == fruit;
}
int get hashCode {
var hash = _SystemHash.combine(0, runtimeType.hashCode);
hash = _SystemHash.combine(hash, fruit.hashCode);
return _SystemHash.finish(hash);
}
}
mixin FruitsRef on AutoDisposeProviderRef<String> {
/// The parameter `fruit` of this provider.
Fruit get fruit;
}
class _FruitsProviderElement extends AutoDisposeProviderElement<String>
with FruitsRef {
_FruitsProviderElement(super.provider);
Fruit get fruit => (origin as FruitsProvider).fruit;
}
// ignore_for_file: type=lint
// ignore_for_file: subtype_of_sealed_class, invalid_use_of_internal_member, invalid_use_of_visible_for_testing_member
文法の勉強ばかりしてもつまらないから、Widgetで使うにはどうすればいいのか実験してみた!
import 'package:dart_three_example/example/record/provider/fruit.dart';
import 'package:flutter/material.dart';
import 'package:flutter_riverpod/flutter_riverpod.dart';
class FruitKind extends ConsumerWidget {
const FruitKind({super.key});
Widget build(BuildContext context, WidgetRef ref) {
// 変数を1個ずつ定義して、値を使う。
final apple = ref.watch(fruitsProvider(Fruit.apple));
final banana = ref.watch(fruitsProvider(Fruit.banana));
final orange = ref.watch(fruitsProvider(Fruit.orange));
return Scaffold(
appBar: AppBar(
title: const Text('Fruit Kind'),
),
body: Center(
child: Column(
children: [
// 後は、使うだけ。
Text(apple),
Text(banana),
Text(orange),
],
),
),
);
}
}
main.dartでimportしてビルドしてみてください。
main.dart
import 'package:dart_three_example/example/record/ui/fruit_kind.dart';
import 'package:flutter/material.dart';
import 'package:flutter_riverpod/flutter_riverpod.dart';
void main() {
runApp(const ProviderScope(child: MyApp()));
}
class MyApp extends StatelessWidget {
const MyApp({super.key});
Widget build(BuildContext context) {
return MaterialApp(
title: 'Flutter Demo',
theme: ThemeData(
colorScheme: ColorScheme.fromSeed(seedColor: Colors.deepPurple),
useMaterial3: true,
),
home: const FruitKind(),
);
}
}
なぜか色がついてない???、まあいいか。
thoughts
すごく単純だけど、どこにも情報がなかったので、思いつきで作ってみた。誰かのお役に立てそうかなと思って記事を書いてみました。
Discussion