Flutter 如何在firebase和bloc中使用json和序列化？错误：将对象转换为可编码对象失败

这是我的云firestore，看起来像：

错误消息：未处理的异常：将对象转换为可编码的 对象失败：摄影

对我的数据库使用jsonSerialization

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

@JsonSerializable()
class Photography{
  String couplePhoto;
  String female;
  String image_url;
  String info;
  String male;
  AllImages all_images;

  Photography();

  factory Photography.fromJson(Map<String, dynamic> json) => _$PhotographyFromJson(json);
  Map<String,dynamic> toJson() => _$PhotographyToJson(this);
}

@JsonSerializable()
class AllImages {
  List<String> imageUrl = List<String>();

  AllImages();

  factory AllImages.fromJson(Map<String, dynamic> json) => _$AllImagesFromJson(json);
  Map<String,dynamic> toJson() => _$AllImagesToJson(this);
}

之后，我创建了DB类

如何使用模型类？

    class DB {
      final db = Firestore.instance;

     // Stream<QuerySnapshot> initStream() {
     //   return db.collection('photography').snapshots();
     // }

    getPhotography() async {
      return db.collection('photography')
        .document("0yUc5QBGHNNq6WK9CyyF")
        .setData(jsonDecode(jsonEncode(Photography)));
}
    }

    DB db = DB();

---

根据包裹来源：

  /// Writes to the document referred to by this [DocumentReference].
  ///
  /// If the document does not yet exist, it will be created.
  ///
  /// If [merge] is true, the provided data will be merged into an
  /// existing document instead of overwriting.
  Future<void> setData(Map<String, dynamic> data, {bool merge = false}) {
    return Firestore.channel.invokeMethod<void>(
      'DocumentReference#setData',
      <String, dynamic>{
        'app': firestore.app.name,
        'path': path,
        'data': data,
        'options': <String, bool>{'merge': merge},
      },
    );
  }

---

根据包裹来源：

  /// Writes to the document referred to by this [DocumentReference].
  ///
  /// If the document does not yet exist, it will be created.
  ///
  /// If [merge] is true, the provided data will be merged into an
  /// existing document instead of overwriting.
  Future<void> setData(Map<String, dynamic> data, {bool merge = false}) {
    return Firestore.channel.invokeMethod<void>(
      'DocumentReference#setData',
      <String, dynamic>{
        'app': firestore.app.name,
        'path': path,
        'data': data,
        'options': <String, bool>{'merge': merge},
      },
    );
  }

---

谢谢你回答我的问题。先生，不能使用Photography.toJson。photography.fromJson仅可供使用<代码>factory Photography.fromJson（Map json）=>；映射到JSON（）=>u$PhotographyToJson（此）我这样添加的，错误是未处理的异常：将对象转换为可编码对象失败：摄影

Map data=jsonDecode（jsonecode（摄影））；Future postsMap=Firestore.instance.collection（'photography'）.document（“0yUc5QBGHNNq6WK9CyyF”）.setData（数据）刚刚想到。。。方法是
getPhotography
。。。此方法的目的是什么？抱歉，我无法更改方法名称..getPhotography set data的目的..它正在工作..但我不明白，如何从firestore检索数据？我在谷歌上搜索并找到这段代码，
Photography.fromJson（jsonDecode（jsonEncode（snapshot.data））factory Photography.fromJson（Map json）=>；映射到JSON（）=>u$PhotographyToJson（此）我这样添加的，错误是未处理的异常：将对象转换为可编码对象失败：摄影
Map data=jsonDecode（jsonecode（摄影））；Future postsMap=Firestore.instance.collection（'photography'）.document（“0yUc5QBGHNNq6WK9CyyF”）.setData（数据）刚刚想到。。。方法是
getPhotography
。。。此方法的目的是什么？抱歉，我无法更改方法名称..getPhotography set data的目的..它正在工作..但我不明白，如何从firestore检索数据？我在谷歌上搜索并找到这段代码，
Photography.fromJson（jsonDecode（jsonEncode（snapshot.data））                    child: StreamBuilder<Photography>(
                        stream: bloc.outFirestore,
                        initialData: null,
                        builder: (context, snapshot) {
                          if (snapshot.hasData) {
                            return Column(
                                children: buildItem(snapshot.data, bloc));
//                                children: snapshot.data.documents
//                                    .map<Widget>((doc) => buildItem(doc, bloc))
//                                    .toList());
                          } else {
                            return SizedBox();
                          }
                        }),

buildItem(Photography doc, PhotographyBloc bloc) {
...
 child: ClipRRect(
                            borderRadius: BorderRadius.circular(20.0),
                            child: FadeInImage.assetNetwork(
                              placeholder: "assets/images/photography.jpg",
                              image: doc.couplePhoto,
//                              image: doc.data['couplePhoto'],
                              fit: BoxFit.fill,
                            ),
                          ),

  /// Writes to the document referred to by this [DocumentReference].
  ///
  /// If the document does not yet exist, it will be created.
  ///
  /// If [merge] is true, the provided data will be merged into an
  /// existing document instead of overwriting.
  Future<void> setData(Map<String, dynamic> data, {bool merge = false}) {
    return Firestore.channel.invokeMethod<void>(
      'DocumentReference#setData',
      <String, dynamic>{
        'app': firestore.app.name,
        'path': path,
        'data': data,
        'options': <String, bool>{'merge': merge},
      },
    );
  }

getPhotography() async {
      return db.collection('photography')
        .document("0yUc5QBGHNNq6WK9CyyF")
        .setData(photography.toJson());
}