错误：未处理的异常：类型“_InternalLinkedHashMap<String, dynamic>”不是“Iterable<dynamic>”类型的子类型

Question

Future<List<Dashboard>> _getDashboard() async {
    print(parameters.toString());
    var response = await http.post(API.get_dashboard2, body: parameters);
    var dashboard = json.decode(response.body);
    var _dashboards = dashboard['success'];

    if (_dashboards == 1) {
      if (response.statusCode == 200) {

        for (listJson in dashboard) {
          _list.add(Dashboard.fromJson(listJson));
        }
      }
    } else if (_dashboards == 0) {
      Toast.show(dashboard['message'], context,
          gravity: Toast.BOTTOM, duration: Toast.LENGTH_SHORT);
    }
  }

我的 Json 响应是：

{"order":[{"total_order":"14","o_cur_month":"0","o_per_month":"4"}],"customer":[{"total_customer":"12","c_cur_month":"0","c_per_month":"1"}],"pending":[{"total_pending_top":"5","total_pending_bottom":"2","cur_month_top":"0","cur_month_bottom":"0","per_month_top":"1","per_month_bottom":"1","six_month_top":"0","six_month_bottom":"0"}],"receiving":[{"total_rec_top":"9","total_rec_bottom":"5","cur_month_top":"0","cur_month_bottom":"0","per_month_top":"2","per_month_bottom":"2","average_sales_tops":"10.0000","average_sales_Bottoms":"6.0000"}],"success":1,"message":"Data Found"}

让我给你我的模型类，从中你可以更正确地理解

class Dashboard {
  List<Order> order;
  List<Customer> customer;
  List<Pending> pending;
  List<Receiving> receiving;
  int success;
  String message;

  Dashboard(
      {this.order,
        this.customer,
        this.pending,
        this.receiving,
        this.success,
        this.message});

  Dashboard.fromJson(Map<String, dynamic> json) {
    if (json['order'] != null) {
      order = new List<Order>();
      json['order'].forEach((v) {
        order.add(new Order.fromJson(v));
      });
    }
    if (json['customer'] != null) {
      customer = new List<Customer>();
      json['customer'].forEach((v) {
        customer.add(new Customer.fromJson(v));
      });
    }
    if (json['pending'] != null) {
      pending = new List<Pending>();
      json['pending'].forEach((v) {
        pending.add(new Pending.fromJson(v));
      });
    }
    if (json['receiving'] != null) {
      receiving = new List<Receiving>();
      json['receiving'].forEach((v) {
        receiving.add(new Receiving.fromJson(v));
      });
    }
    success = json['success'];
    message = json['message'];
  }

  Map<String, dynamic> toJson() {
    final Map<String, dynamic> data = new Map<String, dynamic>();
    if (this.order != null) {
      data['order'] = this.order.map((v) => v.toJson()).toList();
    }
    if (this.customer != null) {
      data['customer'] = this.customer.map((v) => v.toJson()).toList();
    }
    if (this.pending != null) {
      data['pending'] = this.pending.map((v) => v.toJson()).toList();
    }
    if (this.receiving != null) {
      data['receiving'] = this.receiving.map((v) => v.toJson()).toList();
    }
    data['success'] = this.success;
    data['message'] = this.message;
    return data;
  }
}

class Order {
  String totalOrder;
  String oCurMonth;
  String oPerMonth;

  Order({this.totalOrder, this.oCurMonth, this.oPerMonth});

  Order.fromJson(Map<String, dynamic> json) {
    totalOrder = json['total_order'];
    oCurMonth = json['o_cur_month'];
    oPerMonth = json['o_per_month'];
  }

  Map<String, dynamic> toJson() {
    final Map<String, dynamic> data = new Map<String, dynamic>();
    data['total_order'] = this.totalOrder;
    data['o_cur_month'] = this.oCurMonth;
    data['o_per_month'] = this.oPerMonth;
    return data;
  }
}

class Customer {
  String totalCustomer;
  String cCurMonth;
  String cPerMonth;

  Customer({this.totalCustomer, this.cCurMonth, this.cPerMonth});

  Customer.fromJson(Map<String, dynamic> json) {
    totalCustomer = json['total_customer'];
    cCurMonth = json['c_cur_month'];
    cPerMonth = json['c_per_month'];
  }

  Map<String, dynamic> toJson() {
    final Map<String, dynamic> data = new Map<String, dynamic>();
    data['total_customer'] = this.totalCustomer;
    data['c_cur_month'] = this.cCurMonth;
    data['c_per_month'] = this.cPerMonth;
    return data;
  }
}

class Pending {
  String totalPendingTop;
  String totalPendingBottom;
  String curMonthTop;
  String curMonthBottom;
  String perMonthTop;
  String perMonthBottom;
  String sixMonthTop;
  String sixMonthBottom;

  Pending(
      {this.totalPendingTop,
        this.totalPendingBottom,
        this.curMonthTop,
        this.curMonthBottom,
        this.perMonthTop,
        this.perMonthBottom,
        this.sixMonthTop,
        this.sixMonthBottom});

  Pending.fromJson(Map<String, dynamic> json) {
    totalPendingTop = json['total_pending_top'];
    totalPendingBottom = json['total_pending_bottom'];
    curMonthTop = json['cur_month_top'];
    curMonthBottom = json['cur_month_bottom'];
    perMonthTop = json['per_month_top'];
    perMonthBottom = json['per_month_bottom'];
    sixMonthTop = json['six_month_top'];
    sixMonthBottom = json['six_month_bottom'];
  }

  Map<String, dynamic> toJson() {
    final Map<String, dynamic> data = new Map<String, dynamic>();
    data['total_pending_top'] = this.totalPendingTop;
    data['total_pending_bottom'] = this.totalPendingBottom;
    data['cur_month_top'] = this.curMonthTop;
    data['cur_month_bottom'] = this.curMonthBottom;
    data['per_month_top'] = this.perMonthTop;
    data['per_month_bottom'] = this.perMonthBottom;
    data['six_month_top'] = this.sixMonthTop;
    data['six_month_bottom'] = this.sixMonthBottom;
    return data;
  }
}

class Receiving {
  String totalRecTop;
  String totalRecBottom;
  String curMonthTop;
  String curMonthBottom;
  String perMonthTop;
  String perMonthBottom;
  String averageSalesTops;
  String averageSalesBottoms;

  Receiving(
      {this.totalRecTop,
        this.totalRecBottom,
        this.curMonthTop,
        this.curMonthBottom,
        this.perMonthTop,
        this.perMonthBottom,
        this.averageSalesTops,
        this.averageSalesBottoms});

  Receiving.fromJson(Map<String, dynamic> json) {
    totalRecTop = json['total_rec_top'];
    totalRecBottom = json['total_rec_bottom'];
    curMonthTop = json['cur_month_top'];
    curMonthBottom = json['cur_month_bottom'];
    perMonthTop = json['per_month_top'];
    perMonthBottom = json['per_month_bottom'];
    averageSalesTops = json['average_sales_tops'];
    averageSalesBottoms = json['average_sales_Bottoms'];
  }

  Map<String, dynamic> toJson() {
    final Map<String, dynamic> data = new Map<String, dynamic>();
    data['total_rec_top'] = this.totalRecTop;
    data['total_rec_bottom'] = this.totalRecBottom;
    data['cur_month_top'] = this.curMonthTop;
    data['cur_month_bottom'] = this.curMonthBottom;
    data['per_month_top'] = this.perMonthTop;
    data['per_month_bottom'] = this.perMonthBottom;
    data['average_sales_tops'] = this.averageSalesTops;
    data['average_sales_Bottoms'] = this.averageSalesBottoms;
    return data;
  }
}

这是我的仪表板模型类，它可以让您清楚地知道当我出错时，还请指导我解决这个难题

我是这个社区的新手，所以请多多关照

如果有任何方法可以通过它访问这个 json，那就太好了。

提前致谢。

Answer 1

我认为在处理 JSON 数据时应该使用模型/DTO 以避免此类错误。

import 'dart:convert';

class DashboardModel {
  final List<Order>? order;
  final List<Customer>? customer;
  final List<Pending>? pending;
  final List<Receiving>? receiving;
  final int success;
  final String message;
  DashboardModel({
    required this.order,
    required this.customer,
    required this.pending,
    required this.receiving,
    required this.success,
    required this.message,
  });

  DashboardModel copyWith({
    List<Order>? order,
    List<Customer>? customer,
    List<Pending>? pending,
    List<Receiving>? receiving,
    int? success,
    String? message,
  }) {
    return DashboardModel(
      order: order ?? this.order,
      customer: customer ?? this.customer,
      pending: pending ?? this.pending,
      receiving: receiving ?? this.receiving,
      success: success ?? this.success,
      message: message ?? this.message,
    );
  }

  Map<String, dynamic> toMap() {
    return {
      'order': order?.map((x) => x.toMap()).toList(),
      'customer': customer?.map((x) => x.toMap()).toList(),
      'pending': pending?.map((x) => x.toMap()).toList(),
      'receiving': receiving?.map((x) => x.toMap()).toList(),
      'success': success,
      'message': message,
    };
  }

  factory DashboardModel.fromMap(Map<String, dynamic> map) {
    return DashboardModel(
      order: List<Order>.from(
        List.from(map['order']).map(
          (x) => Order.fromMap(x),
        ),
      ),
      customer: List<Customer>.from(
        List.from(map['customer']).map(
          (x) => Customer.fromMap(x),
        ),
      ),
      pending: List<Pending>.from(
        List.from(map['pending']).map(
          (x) => Pending.fromMap(x),
        ),
      ),
      receiving: List<Receiving>.from(
        List.from(map['receiving']).map(
          (x) => Receiving.fromMap(x),
        ),
      ),
      success: map['success'],
      message: map['message'],
    );
  }

  String toJson() => json.encode(toMap());

  factory DashboardModel.fromJson(String source) =>
      DashboardModel.fromMap(json.decode(source));
}

class Order {
  final String total_order;
  final String o_cur_month;
  final String o_per_month;
  Order({
    required this.total_order,
    required this.o_cur_month,
    required this.o_per_month,
  });

  Order copyWith({
    String? total_order,
    String? o_cur_month,
    String? o_per_month,
  }) {
    return Order(
      total_order: total_order ?? this.total_order,
      o_cur_month: o_cur_month ?? this.o_cur_month,
      o_per_month: o_per_month ?? this.o_per_month,
    );
  }

  Map<String, dynamic> toMap() {
    return {
      'total_order': total_order,
      'o_cur_month': o_cur_month,
      'o_per_month': o_per_month,
    };
  }

  factory Order.fromMap(Map<String, dynamic> map) {
    return Order(
      total_order: map['total_order'],
      o_cur_month: map['o_cur_month'],
      o_per_month: map['o_per_month'],
    );
  }

  String toJson() => json.encode(toMap());

  factory Order.fromJson(String source) => Order.fromMap(json.decode(source));
}

class Customer {
  final String total_customer;
  final String c_cur_month;
  final String c_per_month;
  Customer({
    required this.total_customer,
    required this.c_cur_month,
    required this.c_per_month,
  });

  Customer copyWith({
    String? total_customer,
    String? c_cur_month,
    String? c_per_month,
  }) {
    return Customer(
      total_customer: total_customer ?? this.total_customer,
      c_cur_month: c_cur_month ?? this.c_cur_month,
      c_per_month: c_per_month ?? this.c_per_month,
    );
  }

  Map<String, dynamic> toMap() {
    return {
      'total_customer': total_customer,
      'c_cur_month': c_cur_month,
      'c_per_month': c_per_month,
    };
  }

  factory Customer.fromMap(Map<String, dynamic> map) {
    return Customer(
      total_customer: map['total_customer'],
      c_cur_month: map['c_cur_month'],
      c_per_month: map['c_per_month'],
    );
  }

  String toJson() => json.encode(toMap());

  factory Customer.fromJson(String source) =>
      Customer.fromMap(json.decode(source));
}

class Pending {
  final String total_pending_top;
  final String total_pending_bottom;
  final String cur_month_top;
  final String cur_month_bottom;
  final String per_month_top;
  final String per_month_bottom;
  final String six_month_top;
  final String six_month_bottom;
  Pending({
    required this.total_pending_top,
    required this.total_pending_bottom,
    required this.cur_month_top,
    required this.cur_month_bottom,
    required this.per_month_top,
    required this.per_month_bottom,
    required this.six_month_top,
    required this.six_month_bottom,
  });

  Pending copyWith({
    String? total_pending_top,
    String? total_pending_bottom,
    String? cur_month_top,
    String? cur_month_bottom,
    String? per_month_top,
    String? per_month_bottom,
    String? six_month_top,
    String? six_month_bottom,
  }) {
    return Pending(
      total_pending_top: total_pending_top ?? this.total_pending_top,
      total_pending_bottom: total_pending_bottom ?? this.total_pending_bottom,
      cur_month_top: cur_month_top ?? this.cur_month_top,
      cur_month_bottom: cur_month_bottom ?? this.cur_month_bottom,
      per_month_top: per_month_top ?? this.per_month_top,
      per_month_bottom: per_month_bottom ?? this.per_month_bottom,
      six_month_top: six_month_top ?? this.six_month_top,
      six_month_bottom: six_month_bottom ?? this.six_month_bottom,
    );
  }

  Map<String, dynamic> toMap() {
    return {
      'total_pending_top': total_pending_top,
      'total_pending_bottom': total_pending_bottom,
      'cur_month_top': cur_month_top,
      'cur_month_bottom': cur_month_bottom,
      'per_month_top': per_month_top,
      'per_month_bottom': per_month_bottom,
      'six_month_top': six_month_top,
      'six_month_bottom': six_month_bottom,
    };
  }

  factory Pending.fromMap(Map<String, dynamic> map) {
    return Pending(
      total_pending_top: map['total_pending_top'],
      total_pending_bottom: map['total_pending_bottom'],
      cur_month_top: map['cur_month_top'],
      cur_month_bottom: map['cur_month_bottom'],
      per_month_top: map['per_month_top'],
      per_month_bottom: map['per_month_bottom'],
      six_month_top: map['six_month_top'],
      six_month_bottom: map['six_month_bottom'],
    );
  }

  String toJson() => json.encode(toMap());

  factory Pending.fromJson(String source) =>
      Pending.fromMap(json.decode(source));
}

class Receiving {
  final String total_rec_top;
  final String total_rec_bottom;
  final String cur_month_top;
  final String cur_month_bottom;
  final String per_month_top;
  final String per_month_bottom;
  final String average_sales_tops;
  final String average_sales_Bottoms;
  Receiving({
    required this.total_rec_top,
    required this.total_rec_bottom,
    required this.cur_month_top,
    required this.cur_month_bottom,
    required this.per_month_top,
    required this.per_month_bottom,
    required this.average_sales_tops,
    required this.average_sales_Bottoms,
  });

  Receiving copyWith({
    String? total_rec_top,
    String? total_rec_bottom,
    String? cur_month_top,
    String? cur_month_bottom,
    String? per_month_top,
    String? per_month_bottom,
    String? average_sales_tops,
    String? average_sales_Bottoms,
  }) {
    return Receiving(
      total_rec_top: total_rec_top ?? this.total_rec_top,
      total_rec_bottom: total_rec_bottom ?? this.total_rec_bottom,
      cur_month_top: cur_month_top ?? this.cur_month_top,
      cur_month_bottom: cur_month_bottom ?? this.cur_month_bottom,
      per_month_top: per_month_top ?? this.per_month_top,
      per_month_bottom: per_month_bottom ?? this.per_month_bottom,
      average_sales_tops: average_sales_tops ?? this.average_sales_tops,
      average_sales_Bottoms:
          average_sales_Bottoms ?? this.average_sales_Bottoms,
    );
  }

  Map<String, dynamic> toMap() {
    return {
      'total_rec_top': total_rec_top,
      'total_rec_bottom': total_rec_bottom,
      'cur_month_top': cur_month_top,
      'cur_month_bottom': cur_month_bottom,
      'per_month_top': per_month_top,
      'per_month_bottom': per_month_bottom,
      'average_sales_tops': average_sales_tops,
      'average_sales_Bottoms': average_sales_Bottoms,
    };
  }

  factory Receiving.fromMap(Map<String, dynamic> map) {
    return Receiving(
      total_rec_top: map['total_rec_top'],
      total_rec_bottom: map['total_rec_bottom'],
      cur_month_top: map['cur_month_top'],
      cur_month_bottom: map['cur_month_bottom'],
      per_month_top: map['per_month_top'],
      per_month_bottom: map['per_month_bottom'],
      average_sales_tops: map['average_sales_tops'],
      average_sales_Bottoms: map['average_sales_Bottoms'],
    );
  }

  String toJson() => json.encode(toMap());

  factory Receiving.fromJson(String source) =>
      Receiving.fromMap(json.decode(source));
}

这是使用：https://marketplace.visualstudio.com/items?itemName=BendixMa.dart-data-class-generator

然后你可以继续这样做：

Future<DashboardModel?> _getDashboard() async {
  try {
    var res = await http.post(API.get_dashboard2, body: parameters);
    final _dashboard = DashboardModel.fromJson(res.body);

    if (_dashboard.success == 1 && res.statusCode == 200) {
      return _dashboard;
    } else if (_dashboard.success == 0) {
      Toast.show(dashboard.message, context,
          gravity: Toast.BOTTOM, duration: Toast.LENGTH_SHORT);
    }
  } catch (e) {
    print(e.toString());
    return null;
  }
}