Dart Model 对于 Flutter，动态列表

Question

下午好

我需要有关以下 JSON 响应和创建正确 dart model 的帮助。

我已经添加了每种类型，但很难将动态映射到我猜动态列表？

JSON 回复：

{ "status": "Ok", "report": { "35310": { "id": "35310", "country_iso": "NZ", "authorid": "131581", "publish_date": "2021- 10-07 17:42:09", "title": "Scouting Starts Soon" }, "35309": { "id": "35309", "country_iso": "NZ", "authorid": "171165", "publish_date": "2021-10-07 12:25:27", "title": "VOTE VOTE VOTE -Notice #21" }, "35308": { "id": "35308", "country_iso": " NZ", "authorid": "171165", "publish_date": "2021-10-07 12:15:31", "title": "NT Manager Insight-Notice #20" }, "35301": { "id ": "35301", "country_iso": "NZ", "authorid": "171165", "publish_date": "2021-10-05 08:05:17", "title": "GET VOTING-Notice #19 " }, "35261": { "id": "35261", "country_iso": "NZ", "authorid": "171165", "publish_date": "2021-09-25 14:30:01", " title": "BR All Blacks-Notice #18" }, "35259": { "id": "35259", "country_iso": "NZ", "authorid": "131581", "publish_date": "2021- 09-25 04:58:45", "title": "世界杯四分之一决赛," }: "35227": { "id", "35227": "country_iso", "NZ": "authorid", " 131581": "发布日期": "20 21-09-17 20:03,01": "title", "S46 NZ Monday Friendlies" }: "35219": { "id", "35219": "country_iso", "NZ": "authorid", " 131581": "publish_date": "2021-09-14 08:00,12": "title", "世界杯时间:" }: "35177", { "id": "35177", "country_iso": " NZ", "authorid": "171165": "publish_date": "2021-08-22 20,03:35", "title": "Best NZ manager-Opinion #17" }: "35172", { "id ": "35172", "country_iso": "NZ", "authorid": "171165": "publish_date": "2021-08-19 08,53:44", "title": "Interim Journalist-Notice #16 " } }: "brt": "2021-10-10T00:38,33+12:00": "gameDate", { "season": 46, "round": 1, "day": 7 } }

GlobalNews globalNewsFromJson(String str) =>
    GlobalNews.fromJson(json.decode(str));

String globalNewsToJson(GlobalNews data) => json.encode(data.toJson());

class GlobalNews {
  GlobalNews({
    required this.status,
    required this.report,
    required this.brt,
    required this.gameDate,
  });

  String status;
  List<Report> report;
  DateTime brt;
  GameDate gameDate;

  factory GlobalNews.fromJson(Map<String, dynamic> json) => GlobalNews(
        status: json["status"],
        report: Map.from(json["report"])
            .map((k, v) => MapEntry<String, Report>(k, Report.fromJson(v))),
        brt: DateTime.parse(json["brt"]),
        gameDate: GameDate.fromJson(json["gameDate"]),
      );

  Map<String, dynamic> toJson() => {
        "status": status,
        "report": Map.from(report)
            .map((k, v) => MapEntry<String, dynamic>(k, v.toJson())),
        "brt": brt.toIso8601String(),
        "gameDate": gameDate.toJson(),
      };
}

class GameDate {
  GameDate({
    required this.season,
    required this.round,
    required this.day,
  });

  int season;
  int round;
  int day;

  factory GameDate.fromJson(Map<String, dynamic> json) => GameDate(
        season: json["season"],
        round: json["round"],
        day: json["day"],
      );

  Map<String, dynamic> toJson() => {
        "season": season,
        "round": round,
        "day": day,
      };
}

class Report {
  Report({
    required this.id,
    required this.countryIso,
    required this.authorid,
    required this.publishDate,
    required this.title,
  });

  String id;
  String countryIso;
  String authorid;
  DateTime publishDate;
  String title;

  factory Report.fromJson(Map<String, dynamic> json) => Report(
        id: json["id"],
        countryIso: json["country_iso"],
        authorid: json["authorid"],
        publishDate: DateTime.parse(json["publish_date"]),
        title: json["title"],
      );

  Map<String, dynamic> toJson() => {
        "id": id,
        "country_iso": countryIso,
        "authorid": authorid,
        "publish_date": publishDate.toIso8601String(),
        "title": title,
      };
}

感谢您的帮助，可以提供任何帮助或信息

Answer 1

我建议像下面这样更改您的回复。 report字段包含一组报告对象。 如果你像这样格式化，你可以使用像这样的代码生成工具来轻松生成 model class。 小陷阱 - 大多数工具都不是 null 安全的：（如果你找到一个请评论

{
    "status": "Ok",
    "report": [
        {
            "id": "35172",
            "country_iso": "NZ",
            "authorid": "171165",
            "publish_date": "2021-08-19 08:53:44",
            "title": "Interim Journalist-Notice #16"
        },
        {
            "id": "35177",
            "country_iso": "NZ",
            "authorid": "171165",
            "publish_date": "2021-08-22 20:03:35",
            "title": "Best NZ manager-Opinion #17"
        }
    ],
    "brt": "2021-10-10T00:38:33+12:00",
    "gameDate": {
        "season": 46,
        "round": 1,
        "day": 7
    }
}

从工具生成 model 代码

class GlobalNews {
  String status;
  List<Report> report;
  String brt;
  GameDate gameDate;

  GlobalNews({this.status, this.report, this.brt, this.gameDate});

  GlobalNews.fromJson(Map<String, dynamic> json) {
    status = json['status'];
    if (json['report'] != null) {
      report = new List<Report>();
      json['report'].forEach((v) {
        report.add(new Report.fromJson(v));
      });
    }
    brt = json['brt'];
    gameDate = json['gameDate'] != null
        ? new GameDate.fromJson(json['gameDate'])
        : null;
  }

  Map<String, dynamic> toJson() {
    final Map<String, dynamic> data = new Map<String, dynamic>();
    data['status'] = this.status;
    if (this.report != null) {
      data['report'] = this.report.map((v) => v.toJson()).toList();
    }
    data['brt'] = this.brt;
    if (this.gameDate != null) {
      data['gameDate'] = this.gameDate.toJson();
    }
    return data;
  }
}

class Report {
  String id;
  String countryIso;
  String authorid;
  String publishDate;
  String title;

  Report(
      {this.id, this.countryIso, this.authorid, this.publishDate, this.title});

  Report.fromJson(Map<String, dynamic> json) {
    id = json['id'];
    countryIso = json['country_iso'];
    authorid = json['authorid'];
    publishDate = json['publish_date'];
    title = json['title'];
  }

  Map<String, dynamic> toJson() {
    final Map<String, dynamic> data = new Map<String, dynamic>();
    data['id'] = this.id;
    data['country_iso'] = this.countryIso;
    data['authorid'] = this.authorid;
    data['publish_date'] = this.publishDate;
    data['title'] = this.title;
    return data;
  }
}

class GameDate {
  int season;
  int round;
  int day;

  GameDate({this.season, this.round, this.day});

  GameDate.fromJson(Map<String, dynamic> json) {
    season = json['season'];
    round = json['round'];
    day = json['day'];
  }

  Map<String, dynamic> toJson() {
    final Map<String, dynamic> data = new Map<String, dynamic>();
    data['season'] = this.season;
    data['round'] = this.round;
    data['day'] = this.day;
    return data;
  }
}

如果你不能改变你的 JSON 改变GlobalNews.fromJson代码如下

GlobalNews.fromJson(Map<String, dynamic> json) {
    status = json['status'];
    if (json['report'] != null) {
      report = [];
      Map<String, dynamic> reportMap = json['report'];
      reportMap.forEach((id, data) {
        report.add(new Report.fromJson(data));
      });
    }
    brt = json['brt'];
    gameDate =
        json['gameDate'] != null ? GameDate.fromJson(json['gameDate']) : null;
  }

Answer 2

您可以尝试json_serializable package。它是一个 Dart 构建系统构建器，用于处理 JSON。一旦您使用这个 package，您就不需要手动编写那么大的代码。 此 package 将自动为您生成。