DateTime type and nested member not decoded correctly.

[jaggerwang]

Problem

code

import 'package:meta/meta.dart';
import 'package:json_annotation/json_annotation.dart';

part 'tumblr_post.g.dart';

@JsonSerializable()
@immutable
class TumblrPostEntity extends Object with _$TumblrPostEntitySerializerMixin {
  final int id;
  final String url;
  @JsonKey(name: 'short_url')
  final String shortUrl;
  final String type;
  final String format;
  final List<String> tags;
  @JsonKey(name: 'reblog_key')
  final String reblogKey;
  final _TumblrPostSource source;
  @JsonKey(name: 'is_liked')
  final bool isLiked;
  final String creator;
  @JsonKey(name: 'post_at')
  final DateTime postAt;

  TumblrPostEntity({
    this.id = 0,
    this.url = '',
    this.shortUrl = '',
    this.type = '',
    this.format = '',
    this.tags = const [],
    this.reblogKey = '',
    source,
    this.isLiked = false,
    this.creator = '',
    postAt,
  })  : this.source = source ?? _TumblrPostSource(),
        this.postAt = postAt ?? DateTime.fromMillisecondsSinceEpoch(0);

  factory TumblrPostEntity.fromJson(Map<String, dynamic> json) {
    json['source'] = _TumblrPostSource.fromJson(json['source']);
    return _$TumblrPostEntityFromJson(json);
  }

  @override
  String toString() => 'TumblrPostEntity${toJson()}';
}

@JsonSerializable()
@immutable
class _TumblrPostSource extends Object with _$_TumblrPostSourceSerializerMixin {
  final String title;
  final String url;

  _TumblrPostSource({
    this.title = '',
    this.url = '',
  });

  factory _TumblrPostSource.fromJson(Map<String, dynamic> json) =>
      _$_TumblrPostSourceFromJson(json);

  @override
  String toString() => '_TumblrPostSource${toJson()}';
}

generated

// GENERATED CODE - DO NOT MODIFY BY HAND

part of 'tumblr_post.dart';

// **************************************************************************
// JsonSerializableGenerator
// **************************************************************************

TumblrPostEntity _$TumblrPostEntityFromJson(Map<String, dynamic> json) {
  return new TumblrPostEntity(
      id: json['id'] as int,
      url: json['url'] as String,
      shortUrl: json['short_url'] as String,
      type: json['type'] as String,
      format: json['format'] as String,
      tags: (json['tags'] as List)?.map((e) => e as String)?.toList(),
      reblogKey: json['reblog_key'] as String,
      source: json['source'],
      isLiked: json['is_liked'] as bool,
      creator: json['creator'] as String,
      postAt: json['post_at']);
}

abstract class _$TumblrPostEntitySerializerMixin {
  int get id;
  String get url;
  String get shortUrl;
  String get type;
  String get format;
  List<String> get tags;
  String get reblogKey;
  _TumblrPostSource get source;
  bool get isLiked;
  String get creator;
  DateTime get postAt;
  Map<String, dynamic> toJson() => <String, dynamic>{
        'id': id,
        'url': url,
        'short_url': shortUrl,
        'type': type,
        'format': format,
        'tags': tags,
        'reblog_key': reblogKey,
        'source': source,
        'is_liked': isLiked,
        'creator': creator,
        'post_at': postAt?.toIso8601String()
      };
}

_TumblrPostSource _$_TumblrPostSourceFromJson(Map<String, dynamic> json) {
  return new _TumblrPostSource(
      title: json['title'] as String, url: json['url'] as String);
}

abstract class _$_TumblrPostSourceSerializerMixin {
  String get title;
  String get url;
  Map<String, dynamic> toJson() =>
      <String, dynamic>{'title': title, 'url': url};
}

There are a few problems:

1. TumblrPostEntity.postAt is a DateTime, it was decoded as postAt: json['post_at']) in generated code, this is not correct.
2. TumblrPostEntity.source is a nested Object, it was decoded simply as source: json['source'], So I have to handle the fromJson method manually.

I'm already using the latest version of json_serializable.

pubspec.yaml

name: tangbole
description: A tumblr client app.

dependencies:
  cookie_jar: ^0.0.4
  cupertino_icons: ^0.1.2
  english_words: ^3.1.0
  dio: ^0.0.14
  flutter:
    sdk: flutter
  flutter_redux: ^0.5.1
  flutter_webview_plugin: ^0.1.6
  json_annotation: ^0.2.9
  logging: ^0.11.3+1
  meta: ^1.1.5
  path_provider: ^0.4.1
  uri: ^0.11.2
  redux: ^3.0.0
  redux_logging: ^0.3.0
  redux_persist: ^0.7.0-rc.2
  redux_persist_flutter: ^0.6.0-rc.1
  validate: ^1.6.0

dev_dependencies:
  build_runner: ^0.9.1
  flutter_driver:
    sdk: flutter
  flutter_test:
    sdk: flutter
  json_serializable: ^0.5.8
  mockito: ^2.2.3

dependency_overrides:
  analyzer: ^0.31.2-alpha.2

flutter:
  uses-material-design: true
  assets:
    - images/lake.jpg

Notice To solve the dependency conflict, I added the dependency_overrides block.

[kevmoo]

You need a type in your ctor.

  TumblrPostEntity({
    this.id = 0,
    this.url = '',
    this.shortUrl = '',
    this.type = '',
    this.format = '',
    this.tags = const [],
    this.reblogKey = '',
    source,
    this.isLiked = false,
    this.creator = '',
    DartTime postAt, // <-- Need `DateTime` here!!!
  })  : this.source = source ?? _TumblrPostSource(),
        this.postAt = postAt ?? DateTime.fromMillisecondsSinceEpoch(0);