将 map 转换为对象 给我 null 属性对象

问：

这是 Retrofit 为我构建的代码，我对其进行了一些更改。

_result 是一个 Response<Map<String，动态>>它使用 dio.fetch（） 获取

    List<ArticleModel> value = _result.data!['articles']
        .map<ArticleModel>(
            (dynamic i) => ArticleModel.fromJson(i as Map<String, dynamic>))
        .toList();

下面是 fromJson ArticleModel 构造函数

class ArticleModel extends ArticleEntity {
  const ArticleModel({
    int? id,
    String? author,
    String? title,
    String? description,
    String? url,
    String? urlToImage,
    String? publishedAt,
    String? content,
  });


  factory ArticleModel.fromJson(Map<String, dynamic> map) {
    return ArticleModel(
      author: map['author'] ?? '',
      title: map['title'] ?? '',
      description: map['description'] ?? '',
      url: map['url'] ?? '',
      urlToImage: map['urlToImage'] ?? '',
      publishedAt: map['publishedAt'] ?? '',
      content: map['content'] ?? '',
    );
  }
}

我向它添加了一些日志，但第二个日志给了我一个具有 null 属性的对象

    log(_result.data!['articles'][0]['title'], name: 'title'); -> gives me correct title string


    List<ArticleModel> value = _result.data!['articles']
        .map<ArticleModel>(
            (dynamic i) => ArticleModel.fromJson(i as Map<String, dynamic>))
        .toList();

    log(value[0].toString(), name: 'articleModel'); -> gives me ArticleModel(null, null, ...)