ライブラリを用いたシリアル化

analysis_options.yaml

@@ -1,2 +1,10 @@
 # https://pub.dev/packages/yumemi_lints
 include: package:yumemi_lints/flutter/3.16.0/recommended.yaml
+
+analyzer:
+  exclude:
+    - "**/*.g.dart"
+    - "**/*.freezed.dart"
+  errors:
+    # https://pub.dev/packages/freezed#install
+    invalid_annotation_target: ignore

build.yaml

@@ -0,0 +1,9 @@
+targets:
+  $default:
+    builders:
+      # https://github.com/google/json_serializable.dart/tree/master/json_serializable#build-configuration
+      json_serializable:
+        options:
+          field_rename: snake
+          # json のデシリアライズ時に発生する Exception を CheckedFromJsonException にまとめる
+          checked: true

lib/date_time_converter.dart

@@ -0,0 +1,53 @@
+import 'package:freezed_annotation/freezed_annotation.dart';
+import 'package:intl/intl.dart';
+
+/// yumemi_weather で用いられる日時形式に変換する JsonConverter
+///
+/// 形式例
+/// - 2020-04-01T12:00:00+09:00
+/// 参照
+/// - https://yumemi-inc.github.io/flutter-training-template/file-___home_runner_work_flutter-training-template_flutter-training-template_packages_yumemi_weather_lib_src_yumemi_weather_base/YumemiWeather/fetchWeather.html
+class DateTimeConverter implements JsonConverter<DateTime, String> {
+  const DateTimeConverter();
+
+  // DateTime#toIso8601String() はマイクロ秒まで出力されるため用いない
+  // タイムゾーンは intl では未実装のため自前で追加する
+  // see: https://api.flutter.dev/flutter/intl/DateFormat-class.html
+  static final DateFormat dateFormatter = DateFormat("yyyy-MM-dd'T'HH:mm:ss");
+
+  static final NumberFormat timeFormatter = NumberFormat('00');
+
+  @override
+  DateTime fromJson(String json) {
+    // DateFormat#parse() では UTC とローカルのタイムゾーン以外対応できない
+    // DateTime.parse() はタイムゾーンを考慮した上で UTC に変更する
+    return DateTime.parse(json).toLocal();
+  }
+
+  @override
+  String toJson(DateTime object) {
+    final dateTimeStr = dateFormatter.format(object);
+    final timeZoneStr = _toTimeZoneString(object.timeZoneOffset);
+    return '$dateTimeStr$timeZoneStr';
+  }
+
+  String _toTimeZoneString(Duration offset) {
+    final inMinutes = offset.inMinutes.abs();
+
+    if (inMinutes == 0) {
+      return 'Z';
+    }
+
+    final String sign;
+    if (offset.isNegative) {
+      sign = '-';
+    } else {
+      sign = '+';
+    }
+
+    final hours = timeFormatter.format(inMinutes ~/ Duration.minutesPerHour);
+    final minutes = timeFormatter.format(inMinutes % Duration.minutesPerHour);
+
+    return '$sign$hours:$minutes';
+  }
+}

lib/forecast_view.dart

@@ -1,6 +1,6 @@
 import 'package:flutter/material.dart';
 import 'package:flutter_svg/flutter_svg.dart';
-import 'package:flutter_training/forecast.dart';
+import 'package:flutter_training/model/forecast.dart';
 
 class ForecastView extends StatelessWidget {
   const ForecastView({

lib/main_screen.dart

@@ -2,8 +2,9 @@ import 'dart:async';
 import 'dart:convert';
 
 import 'package:flutter/material.dart';
-import 'package:flutter_training/forecast.dart';
 import 'package:flutter_training/forecast_view.dart';
+import 'package:flutter_training/model/fetch_weather_request.dart';
+import 'package:flutter_training/model/forecast.dart';
 import 'package:flutter_training/yumemi_weather_error.dart';
 import 'package:yumemi_weather/yumemi_weather.dart';
 
@@ -19,15 +20,16 @@ class _MainScreenState extends State<MainScreen> {
   Forecast? _forecast;
 
   void _fetchForecast() {
-    const request = {
-      'area': 'tokyo',
-      'date': '2023-11-22T00:00:00+09:00',
-    };
-    final requestString = jsonEncode(request);
+    final request = FetchWeatherRequest(
+      area: 'tokyo',
+      date: DateTime.now(),
+    );
+    final requestString = jsonEncode(request.toJson());
 
     final Forecast newForecast;
     try {
-      newForecast = Forecast.from(_yumemiWeather.fetchWeather(requestString));
+      final responseString = _yumemiWeather.fetchWeather(requestString);
+      newForecast = Forecast.fromJsonString(responseString);
     } on YumemiWeatherError catch (e) {
       unawaited(_showErrorDialog(e.toMessage()));
       return;

lib/model/fetch_weather_request.dart

@@ -0,0 +1,16 @@
+import 'package:flutter_training/date_time_converter.dart';
+import 'package:freezed_annotation/freezed_annotation.dart';
+
+part 'fetch_weather_request.freezed.dart';
+part 'fetch_weather_request.g.dart';
+
+@freezed
+class FetchWeatherRequest with _$FetchWeatherRequest {
+  const factory FetchWeatherRequest({
+    required String area,
+    @DateTimeConverter() required DateTime date,
+  }) = _FetchWeatherRequest;
+
+  factory FetchWeatherRequest.fromJson(Map<String, dynamic> json) =>
+      _$FetchWeatherRequestFromJson(json);
+}

lib/model/fetch_weather_request.freezed.dart

@@ -0,0 +1,175 @@
+// coverage:ignore-file
+// GENERATED CODE - DO NOT MODIFY BY HAND
+// ignore_for_file: type=lint
+// ignore_for_file: unused_element, deprecated_member_use, deprecated_member_use_from_same_package, use_function_type_syntax_for_parameters, unnecessary_const, avoid_init_to_null, invalid_override_different_default_values_named, prefer_expression_function_bodies, annotate_overrides, invalid_annotation_target, unnecessary_question_mark
+
+part of 'fetch_weather_request.dart';
+
+// **************************************************************************
+// FreezedGenerator
+// **************************************************************************
+
+T _$identity<T>(T value) => value;
+
+final _privateConstructorUsedError = UnsupportedError(
+    'It seems like you constructed your class using `MyClass._()`. This constructor is only meant to be used by freezed and you are not supposed to need it nor use it.\nPlease check the documentation here for more information: https://github.com/rrousselGit/freezed#custom-getters-and-methods');
+
+FetchWeatherRequest _$FetchWeatherRequestFromJson(Map<String, dynamic> json) {
+  return _FetchWeatherRequest.fromJson(json);
+}
+
+/// @nodoc
+mixin _$FetchWeatherRequest {
+  String get area => throw _privateConstructorUsedError;
+  @DateTimeConverter()
+  DateTime get date => throw _privateConstructorUsedError;
+
+  Map<String, dynamic> toJson() => throw _privateConstructorUsedError;
+  @JsonKey(ignore: true)
+  $FetchWeatherRequestCopyWith<FetchWeatherRequest> get copyWith =>
+      throw _privateConstructorUsedError;
+}
+
+/// @nodoc
+abstract class $FetchWeatherRequestCopyWith<$Res> {
+  factory $FetchWeatherRequestCopyWith(
+          FetchWeatherRequest value, $Res Function(FetchWeatherRequest) then) =
+      _$FetchWeatherRequestCopyWithImpl<$Res, FetchWeatherRequest>;
+  @useResult
+  $Res call({String area, @DateTimeConverter() DateTime date});
+}
+
+/// @nodoc
+class _$FetchWeatherRequestCopyWithImpl<$Res, $Val extends FetchWeatherRequest>
+    implements $FetchWeatherRequestCopyWith<$Res> {
+  _$FetchWeatherRequestCopyWithImpl(this._value, this._then);
+
+  // ignore: unused_field
+  final $Val _value;
+  // ignore: unused_field
+  final $Res Function($Val) _then;
+
+  @pragma('vm:prefer-inline')
+  @override
+  $Res call({
+    Object? area = null,
+    Object? date = null,
+  }) {
+    return _then(_value.copyWith(
+      area: null == area
+          ? _value.area
+          : area // ignore: cast_nullable_to_non_nullable
+              as String,
+      date: null == date
+          ? _value.date
+          : date // ignore: cast_nullable_to_non_nullable
+              as DateTime,
+    ) as $Val);
+  }
+}
+
+/// @nodoc
+abstract class _$$FetchWeatherRequestImplCopyWith<$Res>
+    implements $FetchWeatherRequestCopyWith<$Res> {
+  factory _$$FetchWeatherRequestImplCopyWith(_$FetchWeatherRequestImpl value,
+          $Res Function(_$FetchWeatherRequestImpl) then) =
+      __$$FetchWeatherRequestImplCopyWithImpl<$Res>;
+  @override
+  @useResult
+  $Res call({String area, @DateTimeConverter() DateTime date});
+}
+
+/// @nodoc
+class __$$FetchWeatherRequestImplCopyWithImpl<$Res>
+    extends _$FetchWeatherRequestCopyWithImpl<$Res, _$FetchWeatherRequestImpl>
+    implements _$$FetchWeatherRequestImplCopyWith<$Res> {
+  __$$FetchWeatherRequestImplCopyWithImpl(_$FetchWeatherRequestImpl _value,
+      $Res Function(_$FetchWeatherRequestImpl) _then)
+      : super(_value, _then);
+
+  @pragma('vm:prefer-inline')
+  @override
+  $Res call({
+    Object? area = null,
+    Object? date = null,
+  }) {
+    return _then(_$FetchWeatherRequestImpl(
+      area: null == area
+          ? _value.area
+          : area // ignore: cast_nullable_to_non_nullable
+              as String,
+      date: null == date
+          ? _value.date
+          : date // ignore: cast_nullable_to_non_nullable
+              as DateTime,
+    ));
+  }
+}
+
+/// @nodoc
+@JsonSerializable()
+class _$FetchWeatherRequestImpl implements _FetchWeatherRequest {
+  const _$FetchWeatherRequestImpl(
+      {required this.area, @DateTimeConverter() required this.date});
+
+  factory _$FetchWeatherRequestImpl.fromJson(Map<String, dynamic> json) =>
+      _$$FetchWeatherRequestImplFromJson(json);
+
+  @override
+  final String area;
+  @override
+  @DateTimeConverter()
+  final DateTime date;
+
+  @override
+  String toString() {
+    return 'FetchWeatherRequest(area: $area, date: $date)';
+  }
+
+  @override
+  bool operator ==(dynamic other) {
+    return identical(this, other) ||
+        (other.runtimeType == runtimeType &&
+            other is _$FetchWeatherRequestImpl &&
+            (identical(other.area, area) || other.area == area) &&
+            (identical(other.date, date) || other.date == date));
+  }
+
+  @JsonKey(ignore: true)
+  @override
+  int get hashCode => Object.hash(runtimeType, area, date);
+
+  @JsonKey(ignore: true)
+  @override
+  @pragma('vm:prefer-inline')
+  _$$FetchWeatherRequestImplCopyWith<_$FetchWeatherRequestImpl> get copyWith =>
+      __$$FetchWeatherRequestImplCopyWithImpl<_$FetchWeatherRequestImpl>(
+          this, _$identity);
+
+  @override
+  Map<String, dynamic> toJson() {
+    return _$$FetchWeatherRequestImplToJson(
+      this,
+    );
+  }
+}
+
+abstract class _FetchWeatherRequest implements FetchWeatherRequest {
+  const factory _FetchWeatherRequest(
+          {required final String area,
+          @DateTimeConverter() required final DateTime date}) =
+      _$FetchWeatherRequestImpl;
+
+  factory _FetchWeatherRequest.fromJson(Map<String, dynamic> json) =
+      _$FetchWeatherRequestImpl.fromJson;
+
+  @override
+  String get area;
+  @override
+  @DateTimeConverter()
+  DateTime get date;
+  @override
+  @JsonKey(ignore: true)
+  _$$FetchWeatherRequestImplCopyWith<_$FetchWeatherRequestImpl> get copyWith =>
+      throw _privateConstructorUsedError;
+}

lib/model/forecast.dart

@@ -0,0 +1,28 @@
+import 'dart:convert';
+
+import 'package:flutter_training/model/weather.dart';
+import 'package:freezed_annotation/freezed_annotation.dart';
+
+part 'forecast.freezed.dart';
+part 'forecast.g.dart';
+
+@freezed
+class Forecast with _$Forecast {
+  const factory Forecast({
+    @JsonKey(name: 'weather_condition') required Weather weather,
+    required int maxTemperature,
+    required int minTemperature,
+  }) = _Forecast;
+
+  factory Forecast.fromJson(Map<String, dynamic> json) =>
+      _$ForecastFromJson(json);
+
+  factory Forecast.fromJsonString(String json) {
+    final decoded = jsonDecode(json) as Map<String, dynamic>?;
+    if (decoded == null) {
+      throw Exception('Invalid format: $json.');
+    }
+
+    return Forecast.fromJson(decoded);
+  }
+}