我正在创建一个应用程序来跟踪足球比赛的结果与外部API。我创建的模型提供了实时匹配属性，您可以在下面看到：

import 'package:freezed_annotation/freezed_annotation.dart';

part 'live_match_tile_model.freezed.dart';
part 'live_match_tile_model.g.dart';

@freezed
class LiveMatchTileModel with _$LiveMatchTileModel {
    const factory LiveMatchTileModel({
        Fixture? fixture,
        League? league,
        Goals? teams,
        Goals? goals,
        Score? score,
        List<Event>? events,
    }) = _LiveMatchTileModel;

    factory LiveMatchTileModel.fromJson(Map<String, dynamic> json) => _$LiveMatchTileModelFromJson(json);
}

@freezed
class Event with _$Event {
    const factory Event({
        Time? time,
        Team? team,
        Assist? player,
        Assist? assist,
        String? type,
        String? detail,
        dynamic comments,
    }) = _Event;

    factory Event.fromJson(Map<String, dynamic> json) => _$EventFromJson(json);
}

@freezed
class Assist with _$Assist {
    const factory Assist({
        dynamic id,
        dynamic name,
    }) = _Assist;

    factory Assist.fromJson(Map<String, dynamic> json) => _$AssistFromJson(json);
}

@freezed
class Team with _$Team {
    const factory Team({
        int? id,
        String? name,
        String? logo,
        dynamic winner,
    }) = _Team;

    factory Team.fromJson(Map<String, dynamic> json) => _$TeamFromJson(json);
}

@freezed
class Time with _$Time {
    const factory Time({
        int? elapsed,
        dynamic extra,
    }) = _Time;

    factory Time.fromJson(Map<String, dynamic> json) => _$TimeFromJson(json);
}

@freezed
class Fixture with _$Fixture {
    const factory Fixture({
        int? id,
        dynamic referee,
        String? timezone,
        DateTime? date,
        int? timestamp,
        Periods? periods,
        Venue? venue,
        Status? status,
    }) = _Fixture;

    factory Fixture.fromJson(Map<String, dynamic> json) => _$FixtureFromJson(json);
}

@freezed
class Periods with _$Periods {
    const factory Periods({
        int? first,
        dynamic second,
    }) = _Periods;

    factory Periods.fromJson(Map<String, dynamic> json) => _$PeriodsFromJson(json);
}

@freezed
class Status with _$Status {
    const factory Status({
        String? long,
        String? short,
        int? elapsed,
    }) = _Status;

    factory Status.fromJson(Map<String, dynamic> json) => _$StatusFromJson(json);
}

@freezed
class Venue with _$Venue {
    const factory Venue({
        int? id,
        String? name,
        String? city,
    }) = _Venue;

    factory Venue.fromJson(Map<String, dynamic> json) => _$VenueFromJson(json);
}

@freezed
class Goals with _$Goals {
    const factory Goals({
        dynamic home,
        dynamic away,
    }) = _Goals;

    factory Goals.fromJson(Map<String, dynamic> json) => _$GoalsFromJson(json);
}

@freezed
class League with _$League {
    const factory League({
        int? id,
        String? name,
        String? country,
        String? logo,
        String? flag,
        int? season,
        String? round,
    }) = _League;

    factory League.fromJson(Map<String, dynamic> json) => _$LeagueFromJson(json);
}

@freezed
class Score with _$Score {
    const factory Score({
        Goals? halftime,
        Goals? fulltime,
        Goals? extratime,
        Goals? penalty,
    }) = _Score;

    factory Score.fromJson(Map<String, dynamic> json) => _$ScoreFromJson(json);
}

我使用PrettyDioLogger来检查响应，一切似乎都在工作，但提供的数据没有显示的UI。当我试图检查出了什么问题时，我注意到我的cubit函数得到的结果告诉我：
“类型'Null'不是类型强制转换中类型Map<String，dynamic>的子类型”。
下面是Cubit结构：

import 'package:flutter_bloc/flutter_bloc.dart';
import 'package:freezed_annotation/freezed_annotation.dart';
import 'package:score_live/repositories/home_screen_repository.dart';
import 'package:score_live/core/enums.dart';
import 'package:score_live/models/live_match_tile_model.dart';

part 'home_state.dart';

part 'home_cubit.freezed.dart';

class HomeCubit extends Cubit<HomeState> {
  HomeCubit(this.homeScreenRepository) : super(const HomeState());

  final HomeScreenRepository homeScreenRepository;

  Future<void> fetchLiveMatches() async {
    try {
      final liveMatches = await homeScreenRepository.fetchLiveMatches();
      emit(state.copyWith(liveMatchTileModel: liveMatches));
    } catch (error) {
      emit(state.copyWith(errorMessage: error.toString()));
      print(error); // Here app prints the previously mentioned error in debug console
    }
  }
}

我试图为生成的模型的动态属性给予默认值，或者将它们的类型更改为动态之外的类型，添加“！“和零感知““在使用API数据的地方进行检查，JSON键也没有帮助。以下是API响应的示例：

{
  "get": "fixtures",
  "parameters": {
    "live": "all"
  },
  "errors": [],
  "results": 35,
  "paging": {
    "current": 1,
    "total": 1
  },
  "response": [
    {
      "fixture": {
        "id": 999014,
        "referee": null,
        "timezone": "UTC",
        "date": "2023-06-28T15:30:00+00:00",
        "timestamp": 1687966200,
        "periods": {
          "first": 1687966200,
          "second": null
        },
        "venue": {
          "id": 6351,
          "name": "Järvenpään keskuskenttä",
          "city": "Järvenpää"
        },
        "status": {
          "long": "First Half",
          "short": "1H",
          "elapsed": 12
        }
      },
      "league": {
        "id": 245,
        "name": "Ykkönen",
        "country": "Finland",
        "logo": "https://media-2.api-sports.io/football/leagues/245.png",
        "flag": "https://media-1.api-sports.io/flags/fi.svg",
        "season": 2023,
        "round": "Regular Season - 12"
      },
      "teams": {
        "home": {
          "id": 9173,
          "name": "JäPS",
          "logo": "https://media-2.api-sports.io/football/teams/9173.png",
          "winner": null
        },
        "away": {
          "id": 9189,
          "name": "SalPa",
          "logo": "https://media-3.api-sports.io/football/teams/9189.png",
          "winner": null
        }
      },
      "goals": {
        "home": 0,
        "away": 0
      },
      "score": {
        "halftime": {
          "home": 0,
          "away": 0
        },
        "fulltime": {
          "home": null,
          "away": null
        },
        "extratime": {
          "home": null,
          "away": null
        },
        "penalty": {
          "home": null,
          "away": null
        }
      },
      "events": [
        {
          "time": {
            "elapsed": 7,
            "extra": null
          },
          "team": {
            "id": 9189,
            "name": "SalPa",
            "logo": "https://media-3.api-sports.io/football/teams/9189.png"
          },
          "player": {
            "id": null,
            "name": null
          },
          "assist": {
            "id": null,
            "name": null
          },
          "type": "Card",
          "detail": "Yellow Card",
          "comments": null
        }
      ]}]
    }