错误说它无法创建 ApplicableFlight FlightSegmentReference 有问题 List dynamic is not a subtype of type 'Map String, dynamic

这是使用json.decode和fromJson的地方

var map = json.decode(response.body) as Map<String, dynamic>;
ResponseGate responseGate = new ResponseGate.fromJson(map);

这是 json.decode 的输出片段

..,ApplicableFlight: {FlightReferences: F1,FlightSegmentReference: {ref: 0199,ClassOfService: {refs:ABCD,Code: {SeatsLeft: 6,content: Z},MarketingName:world}},OriginDestinationReferences:FF},

response.body 如下所示:

 { ..,
   {
                                    "ApplicableFlight": {
                                        "FlightReferences": "F1",
                                        "FlightSegmentReference": {
                                            "ref": "0199",
                                            "ClassOfService": {
                                                "refs": "FBCODE1ADT",
                                                "Code": {
                                                    "SeatsLeft": 7,
                                                    "content": "Z"
                                                },
                                                "MarketingName": "world"
                                            }
                                        },
                                        "OriginDestinationReferences": "FF"
                                    }
                                },}

这是定义对象和ResponseGate.fromJson(map)寻找

x. Dart

@JsonSerializable()
class ResponseGate {
  @JsonKey(name: "Offer")
  List<Offer> offer;

  ResponseGate(this.offer);
  factory ResponseGate.fromJson(Map<String, dynamic> json) =>
      _$ResponseGateFromJson(json);
 }

 @JsonSerializable()
 class Offer {
 @JsonKey(name: "PricedOffer")
  PricedOffer pricedOffer;

  Offer(this.pricedOffer);
  factory Offer.fromJson(Map<String, dynamic> json) =>
      _$OfferFromJson(json);
}


  @JsonSerializable()
    class PricedOffer {
      @JsonKey(name: "Associations")
      List<Associates> listOfAssociations;


      PricedOffer(this.listOfAssociations);
      factory PricedOffer.fromJson(Map<String, dynamic> json) =>
          _$PricedOfferFromJson(json);
    }

@JsonSerializable()
class Associates {
  @JsonKey(name: "ApplicableFlight")
  ApplicableFlight applicableFlight;

  Associates(this.applicableFlight);
  factory Associates.fromJson(Map<String, dynamic> json) =>
      _$AssociatesFromJson(json);
}
@JsonSerializable()
class ApplicableFlight {
  @JsonKey(name: "FlightReferences")
  var flightReference;
  @JsonKey(name: "FlightSegmentReference")
  FlightSegmentReference flightSegmentReference;

  @JsonKey(name: "OriginDestinationReferences")
  var originDestinationReferences;

  ApplicableFlight(this.flightReference, this.flightSegmentReference,
      this.originDestinationReferences);

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

@JsonSerializable()
class FlightSegmentReference {
  @JsonKey(name: "ref")
  var ref;
  @JsonKey(name: "ClassOfService")
  ClassOfService classOfService;

  FlightSegmentReference(this.ref, this.classOfService);

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

@JsonSerializable()
class ClassOfService {
  @JsonKey(name: "refs")
  var refs;
  @JsonKey(name: "Code")
  Code code;
  @JsonKey(name: "MarketingName")
  var marketingName;

  ClassOfService(this.refs, this.code, this.marketingName);
  factory ClassOfService.fromJson(Map<String, dynamic> json) =>
      _$ClassOfServiceFromJson(json);
}

@JsonSerializable()
class Code {
  @JsonKey(name: "SeatsLeft")
  var seatLeft;
  @JsonKey(name: "content")
  var content;

  Code(this.seatLeft, this.content);
  factory Code.fromJson(Map<String, dynamic> json) => _$CodeFromJson(json);
}

x.g.dart

ApplicableFlight _$ApplicableFlightFromJson(Map<String, dynamic> json) 

{
  return $checkedNew('ApplicableFlight', json, () {
    $checkKeys(json, allowedKeys: const [
      'FlightReferences',
      'FlightSegmentReference',
      'OriginDestinationReferences'
    ]);
    final val = ApplicableFlight(
        $checkedConvert(json, 'FlightReferences', (v) => v),
        $checkedConvert(
            json,
            'FlightSegmentReference',
            (v) => v == null
                ? null
                : FlightSegmentReference.fromJson(v as Map<String, dynamic>)),
        $checkedConvert(json, 'OriginDestinationReferences', (v) => v));
    return val;
  }, fieldKeyMap: const {
    'flightReference': 'FlightReferences',
    'flightSegmentReference': 'FlightSegmentReference',
    'originDestinationReferences': 'OriginDestinationReferences'
  });
}

FlightSegmentReference _$FlightSegmentReferenceFromJson(
    Map<String, dynamic> json) {
  return $checkedNew('FlightSegmentReference', json, () {
    $checkKeys(json, allowedKeys: const ['ref', 'ClassOfService']);
    final val = FlightSegmentReference(
        $checkedConvert(json, 'ref', (v) => v),
        $checkedConvert(
            json,
            'ClassOfService',
            (v) => v == null
                ? null
                : ClassOfService.fromJson(v as Map<String, dynamic>)));
    return val;
  }, fieldKeyMap: const {'classOfService': 'ClassOfService'});
}

ClassOfService _$ClassOfServiceFromJson(Map<String, dynamic> json) {
  return $checkedNew('ClassOfService', json, () {
    $checkKeys(json, allowedKeys: const ['refs', 'Code', 'MarketingName']);
    final val = ClassOfService(
        $checkedConvert(json, 'refs', (v) => v),
        $checkedConvert(json, 'Code',
            (v) => v == null ? null : Code.fromJson(v as Map<String, dynamic>)),
        $checkedConvert(json, 'MarketingName', (v) => v));
    return val;
  }, fieldKeyMap: const {'code': 'Code', 'marketingName': 'MarketingName'});
}

Code _$CodeFromJson(Map<String, dynamic> json) {
  return $checkedNew('Code', json, () {
    $checkKeys(json, allowedKeys: const ['SeatsLeft', 'content']);
    final val = Code($checkedConvert(json, 'SeatsLeft', (v) => v),
        $checkedConvert(json, 'content', (v) => v));
    return val;
  }, fieldKeyMap: const {'seatLeft': 'SeatsLeft'});
}

已更新

我查看了 api 响应，发现 FlightSegmentReference 以两种不同的方式出现，如下所示。我该如何设计这样的格式？

{
"Offer": [
    {
        "PricedOffer": {
            "Associations": [
                {
                    "ApplicableFlight": {
                        "FlightReferences": "Flight1",
                        "FlightSegmentReference": {
                            "ref": "99",
                            "ClassOfService": {
                                "refs": "ADT",
                                "Code": {
                                    "SeatsLeft": 9,
                                    "content": "J"
                                },
                                "MarketingName": " World"
                            }
                        },
                        "OriginDestinationReferences": "OD1"
                    }
                },
                {
                    "ApplicableFlight": {
                        "FlightReferences": "Flight11",
                        "FlightSegmentReference": {
                            "ref": "BA0138",
                            "ClassOfService": {
                                "refs": "FBCODE1ADT",
                                "Code": {
                                    "SeatsLeft": 9,
                                    "content": "J"
                                },
                                "MarketingName": "Club World"
                            }
                        },
                        "OriginDestinationReferences": "OD2"
                    }
                }
            ]
        }
    },
    {
        "PricedOffer": {
            "Associations": [
                {
                    "ApplicableFlight": {
                        "FlightReferences": "Fl",
                        "FlightSegmentReference": [
                            {
                                "ref": "02",
                                "ClassOfService": {
                                    "refs": "FBCODE2ADT",
                                    "Code": {
                                        "SeatsLeft": 9,
                                        "content": "J"
                                    },
                                    "MarketingName": "Club World"
                                }
                            },
                            {
                                "ref": "58",
                                "ClassOfService": {
                                    "refs": "1ADT",
                                    "Code": {
                                        "SeatsLeft": 9,
                                        "content": "J"
                                    },
                                    "MarketingName": "B"
                                }
                            }
                        ],
                        "OriginDestinationReferences": "1"
                    }
                },
                {
                    "ApplicableFlight": {
                        "FlightReferences": "Fl11",
                        "FlightSegmentReference": {
                            "ref": "8",
                            "ClassOfService": {
                                "refs": "E1ADT",
                                "Code": {
                                    "SeatsLeft": 9,
                                    "content": "J"
                                },
                                "MarketingName": "orld"
                            }
                        },
                        "OriginDestinationReferences": "O"
                    }
                }
            ]
        }
    }
]}

最佳答案

 List<dynamic> areas = new List();
 areas = json.decode(response.body);
 String _mySelection1;
 Container(
        height: 50,
        child: DropdownButton<String>(
          isExpanded: true,
          isDense: true,
          hint: new Text("Select Location"),
          value: _mySelection1,
          onChanged:(String newValue) {
            setState(() {
              _mySelection1 = newValue;
            });
            print (_mySelection1);
          },
          items: areas.map((map){
            return DropdownMenuItem<String>(
              value: map["area_id"],
              child: Text(
                map["name"],
              ),
            );
          }).toList(),
        ),
      ),

这是解决此类问题的示例。我的 json 也收到 Mam 响应。但我是这样处理的。希望这个例子对你有帮助。这是我的回复。

[{"id":"1","name":"Dermatology"},{"id":"2","name":"Cancer of Female Reproductive System"},{"id":"3","name":"Cardiology"},{"id":"4","name":"Dentistry"},{"id":"5","name":"Allergy & Immunology"},{"id":"6","name":"Anesthesia"},{"id":"7","name":"Colorectal Surgery"},{"id":"8","name":"Endocrinology (Diabetes, Hormones, Thyroid, etc.)"},{"id":"9","name":"ENT (Ear, Nose & Throat, Otorhinolaryngology)"},{"id":"10","name":"Gastroenterology (Stomach, Pancreas and Intestine)"},{"id":"11","name":"General Physician"}]

关于flutter - 如何解决 List<dynamic> is not a subtype of type 'Map<String, dynamic>？，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/57324930/