如何使用内置值构建列表

Question

我有这个问题：

我有一个数组：

[
  {
    "name": "John",
  },
  {
    "name": "Antonio",
  },
  {
    "name": "Simon",
  }
]

我使用built_value，如下我正在尝试反序列化一个json字符串：

library name;

import 'dart:convert';

import 'package:built_collection/built_collection.dart';
import 'package:built_value/built_value.dart';
import 'package:built_value/serializer.dart';

part 'name.g.dart';

abstract class Name implements Built<Name, NameBuilder> {

  String get name;

  Name._();

  factory Name([updates(NameBuilder b)]) = _$Name;

  String toJson() {
    return json.encode(serializers.serializeWith(Name.serializer, this));
  }

  static Name fromJson(String jsonString) {
    return serializers.deserializeWith(
        Name.serializer, json.decode(jsonString));
  }

  static Serializer<Name> get serializer => _$nameSerializer;
}

据我了解，我将获取名称，但如何从中获取 NameResult 列表？

现在我尝试这样做：

library name_result;

import 'dart:convert';

import 'package:built_collection/built_collection.dart';
import 'package:built_value/built_value.dart';
import 'package:built_value/serializer.dart';

part 'name_result.g.dart';

abstract class NameResult implements Built<NameResult, NameResultBuilder> {

  BuiltList<Name> get nameResult;

  NameResult._();

  factory NameResult([updates(NameResultBuilder b)]) = _$NameResult;

  String toJson() {
    return json.encode(serializers.serializeWith(NameResult.serializer, this));
  }

  static NameResult fromJson(String jsonString) {
    return serializers.deserializeWith(
        NameResult.serializer, json.decode(jsonString));
  }

  static Serializer<NameResult> get serializer => _$nameResultSerializer;
}

但我收到以下错误： failed due to: type '_InternalLinkedHashMap<String, dynamic>' is not a subtype of type 'String' in type cast occurred in Instance of 'NameBloc'.

我该如何解决这个问题？

Answer 1

serializers.dart:

const builtListString = FullType(
  BuiltList,
  [FullType(String)],
);

...
final standardSerializers = (serializers.toBuilder()
      ..addBuilderFactory(
        builtListString,
        () => ListBuilder<String>(),
      )
      ..add(Iso8601DateTimeSerializer())
      ..addPlugin(StandardJsonPlugin()))
    .build();

    final json = jsonDecode('[{ ... }]');
    final names = standardSerializers.deserialize(
      json,
      specifiedType: builtListString,
    ) as BuiltList<String>;

如何使用内置值构建列表

How to build a list using built-value

flutter

bloc

built-value