如何从请求中加载对象列表？

Question

我的第一个请求遇到问题，响应是一组对象，我需要帮助

模型类是：

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

List<Event> eventFromJson(String str) => List<Event>.from(json.decode(str).map((x) => Event.fromJson(x)));

String eventToJson(List<Event> data) => json.encode(List<dynamic>.from(data.map((x) => x.toJson())));

class Event {
    Event({
        required this.id,
        required this.state,
        required this.province,
        required this.city,
        required this.latitude,
        required this.longitude,
        required this.startDate,
        required this.endDate,
        required this.openDoors,
        required this.startEventHour,
        required this.endDateHour,
        required this.nameEvent,
        required this.artistname,
        required this.poster,
        required this.enclosure,
        required this.eventType,
    });

    String id;
    String state;
    String province;
    String city;
    String latitude;
    String longitude;
    String startDate;
    String endDate;
    String openDoors;
    String startEventHour;
    String endDateHour;
    String nameEvent;
    String artistname;
    String poster;
    String enclosure;
    String eventType;

    
    factory Event.fromJson(Map<String, dynamic> json) => Event(
        id: json["id"],
        state: json["state"],
        province: json["province"],
        city: json["city"],
        latitude: json["latitude"],
        longitude: json["longitude"],
        startDate: json["startDate"],
        endDate: json["endDate"],
        openDoors: json["openDoors"],
        startEventHour: json["startEventHour"],
        endDateHour: json["endDateHour"],
        nameEvent: json["nameEvent"],
        artistname: json["artistname"],
        poster: json["poster"],
        enclosure: json["enclosure"],
        eventType: json["eventType"],
    );

    Map<String, dynamic> toJson() => {
        "id": id,
        "state": state,
        "province": province,
        "city": city,
        "latitude": latitude,
        "longitude": longitude,
        "startDate": startDate,
        "endDate": endDate,
        "openDoors": openDoors,
        "startEventHour": startEventHour,
        "endDateHour": endDateHour,
        "nameEvent": nameEvent,
        "artistname": artistname,
        "poster": poster,
        "enclosure": enclosure,
        "eventType": eventType,
    };
}

我发出请求的类是：

class MockEventRepository extends EventRepository{

  String _url = 'nevermind';
  Dio _dio =  Dio();
  
  @override
  Future<Event?> getEvent() {

    throw UnimplementedError();
  }
  Future<List<Event>> getEvents({bool refresh = false})async{
    List<Event> events = <Event>[];
    try{
        Response response   = await _dio.get(_url); 
        //Event event = Event.fromJson(response.data);
        String decodedData = json.decode(response.data);
        print(decodedData);
        
         return Future.delayed(const Duration(seconds: 2), () =>events);
         }on DioError catch(e){
           print(e);
           return [];
         }
  }

 
}

我无法读取 url 给我的 3 个事件列表，这是错误：

List' 不是 'Map

类型的子类型

如果你能帮助我，我将非常感激

Answer 1

映射响应中的每个元素后，您应该使用方法 .toList()。

你的代码应该是这样的：

List<Event> eventFromJson(String str) => List<Event>.from(json.decode(str).map((x) => Event.fromJson(x)).toList());