Dart：如何将_InternalLinkedHashMap对象添加到List<dynamic>并适配DataModel

报错原因说明 #

报错Cannot add _InternalLinkedHashMap<String, dynamic> to a List<dynamic>本质是你声明的List泛型和待添加的元素类型不匹配，同时你需要先将Map结构转成DataModel实体，再存入对应泛型的List中，才能避免类型错误。

具体实现步骤 #

1. 定义对应结构的DataModel类 #

编写带fromJson转换方法的实体类：

class CustomDataModel {
  final String url;
  final int id;
  final String? deviceId;
  final List<dynamic> requiredConsents;

  CustomDataModel({
    required this.url,
    required this.id,
    this.deviceId,
    required this.requiredConsents,
  });

  // 从Map转实体的工厂方法
  factory CustomDataModel.fromJson(Map<String, dynamic> json) {
    return CustomDataModel(
      url: json['url'] as String,
      id: json['id'] as int,
      deviceId: json['deviceId'] as String?,
      requiredConsents: json['requiredConsents'] as List,
    );
  }
}

2. 声明对应泛型的目标List #

// 错误声明示例（会触发类型不匹配报错）
// List<dynamic> targetList = []; 

// 正确声明示例，泛型指定为DataModel类型
List<CustomDataModel> dataList = [];

3. 解码JSON转实体后存入List #

import 'dart:convert';

// 假设responseBody为接口返回的JSON字符串
Map<String, dynamic> decodedMap = jsonDecode(responseBody);
// 转成DataModel实体
CustomDataModel model = CustomDataModel.fromJson(decodedMap);
// 存入目标List
dataList.add(model);

4. ListView.builder渲染示例 #

ListView.builder(
  itemCount: dataList.length,
  itemBuilder: (context, index) {
    final currentItem = dataList[index];
    return ListTile(
      title: Text(currentItem.url),
      subtitle: Text('ID: ${currentItem.id}'),
    );
  }
)

内容的提问来源于stack exchange，提问作者Vasil Test