我得到的是 DeviceClass 的实例，而不是实际的数据字段。这是我的数据模型：
import 'package:meta/meta.dart';
import 'dart:convert';
Device deviceFromJson(String str) => Device.fromJson(json.decode(str));
String deviceToJson(Device data) => json.encode(data.toJson());
class Device {
Device({
required this.device,
});
final DeviceClass? device;
factory Device.fromJson(Map<String, dynamic> json) => Device(
device: json["device"] == null ? null : DeviceClass.fromJson(json["device"]),
);
Map<String, dynamic> toJson() => {
"device": device == null ? null : device?.toJson(),
};
}
class DeviceClass {
DeviceClass({
required this.deviceId,
required this.publicId,
required this.companyId,
required this.company,
required this.label,
required this.mobileProviderId,
required this.mobileProvider,
required this.hologramDeviceId,
required this.hologramLinkId,
required this.firmwareVersionId,
required this.version,
required this.formattedVersion,
required this.deviceTypeId,
required this.deviceType,
required this.ipAddress,
required this.recordInterval,
required this.uploadInterval,
required this.powerMode,
required this.connectivity,
required this.connectivityClass,
required this.usersLastRecordDate,
required this.gmtLastRecordDate,
required this.battery,
required this.batteryPercentage,
required this.batteryClass,
required this.batteryIcon,
required this.signalQuality,
required this.signalQualityClass,
required this.signalQualityText,
required this.signalQualityIcon,
required this.queuedRecords,
required this.command,
required this.status,
required this.statusClass,
required this.purchaseDate,
required this.warrantyPeriod,
required this.warrantyExpires,
required this.warrantyStatus,
required this.temperatureClass,
required this.temperatureMetric,
required this.temperatureImperial,
required this.surgeProtection,
required this.totalProducts,
@required this.temperatureLowThreshold,
@required this.temperatureHighThreshold,
@required this.notes,
@required this.importId,
required this.deleted,
required this.createdBy,
required this.lastUpdatedBy,
@required this.deletedBy,
@required this.dateCreated,
required this.dateModified,
@required this.dateDeleted,
required this.scope,
required this.owner,
@required this.links,
@required this.ports,
@required this.iotDeviceTags,
@required this.entityAddresses,
@required this.availablePorts,
@required this.mobile,
});
final String deviceId;
final String publicId;
final String companyId;
final String company;
final String label;
final String mobileProviderId;
final String mobileProvider;
final String hologramDeviceId;
final String hologramLinkId;
final String firmwareVersionId;
final String version;
final String formattedVersion;
final String deviceTypeId;
final String deviceType;
final String ipAddress;
final String recordInterval;
final String uploadInterval;
final String powerMode;
final String connectivity;
final String connectivityClass;
final String usersLastRecordDate;
final DateTime? gmtLastRecordDate;
final String battery;
final String batteryPercentage;
final String batteryClass;
final String batteryIcon;
final String signalQuality;
final String signalQualityClass;
final String signalQualityText;
final String signalQualityIcon;
final String queuedRecords;
final String command;
final String status;
final String statusClass;
final DateTime? purchaseDate;
final String warrantyPeriod;
final DateTime? warrantyExpires;
final String warrantyStatus;
final String temperatureClass;
final String temperatureMetric;
final String temperatureImperial;
final String surgeProtection;
final String totalProducts;
final dynamic temperatureLowThreshold;
final dynamic temperatureHighThreshold;
final dynamic notes;
final dynamic importId;
final String deleted;
final String createdBy;
final String lastUpdatedBy;
final dynamic deletedBy;
final dynamic dateCreated;
final String dateModified;
final dynamic dateDeleted;
final String scope;
final String owner;
final DeviceLinks? links;
final List<Port>? ports;
final List<IotDeviceTag>? iotDeviceTags;
final List<EntityAddress>? entityAddresses;
final List<String>? availablePorts;
final Mobile? mobile;
factory DeviceClass.fromJson(Map<String, dynamic> json) => DeviceClass(
deviceId: json["device_id"] ?? 'null',
publicId: json["public_id"] ?? 'null',
companyId: json["company_id"] ?? 'null',
company: json["company"] ?? 'null',
label: json["label"] ?? 'null',
mobileProviderId: json["mobile_provider_id"] == null ? 'null' : json["mobile_provider_id"],
mobileProvider: json["mobile_provider"] == null ? 'null' : json["mobile_provider"],
hologramDeviceId: json["hologram_device_id"] == null ? 'null' : json["hologram_device_id"],
hologramLinkId: json["hologram_link_id"] == null ? 'null' : json["hologram_link_id"],
firmwareVersionId: json["firmware_version_id"] == null ? 'null' : json["firmware_version_id"],
version: json["version"] == null ? 'null' : json["version"],
formattedVersion: json["formatted_version"] == null ? 'null' : json["formatted_version"],
deviceTypeId: json["device_type_id"] == null ? 'null' : json["device_type_id"],
deviceType: json["device_type"] == null ? 'null' : json["device_type"],
ipAddress: json["ip_address"] == null ? 'null' : json["ip_address"],
recordInterval: json["record_interval"] == null ? 'null' : json["record_interval"],
uploadInterval: json["upload_interval"] == null ? 'null' : json["upload_interval"],
powerMode: json["power_mode"] == null ? 'null' : json["power_mode"],
connectivity: json["connectivity"] == null ? 'null' : json["connectivity"],
connectivityClass: json["connectivity_class"] == null ? 'null' : json["connectivity_class"],
usersLastRecordDate: json["users_last_record_date"] == null ? 'null' : json["users_last_record_date"],
gmtLastRecordDate: json["gmt_last_record_date"] == null ? null : DateTime.parse(json["gmt_last_record_date"]),
battery: json["battery"] == null ? 'null' : json["battery"],
batteryPercentage: json["battery_percentage"] == null ? 'null' : json["battery_percentage"],
batteryClass: json["battery_class"] == null ? 'null' : json["battery_class"],
batteryIcon: json["battery_icon"] == null ? 'null' : json["battery_icon"],
signalQuality: json["signal_quality"] == null ? 'null' : json["signal_quality"],
signalQualityClass: json["signal_quality_class"] == null ? 'null' : json["signal_quality_class"],
signalQualityText: json["signal_quality_text"] == null ? 'null' : json["signal_quality_text"],
signalQualityIcon: json["signal_quality_icon"] == null ? 'null' : json["signal_quality_icon"],
queuedRecords: json["queued_records"] == null ? 'null' : json["queued_records"],
command: json["command"] == null ? 'null' : json["command"],
status: json["status"] == null ? 'null' : json["status"],
statusClass: json["status_class"] == null ? 'null' : json["status_class"],
purchaseDate: json["purchase_date"] == null ? null : DateTime.parse(json["purchase_date"]),
warrantyPeriod: json["warranty_period"] == null ? 'null' : json["warranty_period"],
warrantyExpires: json["warranty_expires"] == null ? null : DateTime.parse(json["warranty_expires"]),
warrantyStatus: json["warranty_status"] == null ? 'null' : json["warranty_status"],
temperatureClass: json["temperature_class"] == null ? 'null' : json["temperature_class"],
temperatureMetric: json["temperature_metric"] == null ? 'null' : json["temperature_metric"],
temperatureImperial: json["temperature_imperial"] == null ? 'null' : json["temperature_imperial"],
surgeProtection: json["surge_protection"] == null ? 'null' : json["surge_protection"],
totalProducts: json["total_products"] == null ? 'null' : json["total_products"],
temperatureLowThreshold: json["temperature_low_threshold"],
temperatureHighThreshold: json["temperature_high_threshold"],
notes: json["notes"],
importId: json["import_id"],
deleted: json["deleted"] == null ? 'null' : json["deleted"],
createdBy: json["created_by"] == null ? 'null' : json["created_by"],
lastUpdatedBy: json["last_updated_by"] == null ? 'null' : json["last_updated_by"],
deletedBy: json["deleted_by"],
dateCreated: json["date_created"],
dateModified: json["date_modified"] == null ? 'null' : json["date_modified"],
dateDeleted: json["date_deleted"],
scope: json["scope"] == null ? 'null' : json["scope"],
owner: json["owner"] == null ? 'null' : json["owner"],
links: json["links"] == null ? null : DeviceLinks.fromJson(json["links"]),
ports: json["ports"] == null ? null : List<Port>.from(json["ports"].map((x) => Port.fromJson(x))),
iotDeviceTags: json["iot_device_tags"] == null ? null : List<IotDeviceTag>.from(json["iot_device_tags"].map((x) => IotDeviceTag.fromJson(x))),
entityAddresses: json["entity_addresses"] == null ? null : List<EntityAddress>.from(json["entity_addresses"].map((x) => EntityAddress.fromJson(x))),
availablePorts: json["available_ports"] == null ? null : List<String>.from(json["available_ports"].map((x) => x)),
mobile: json["mobile"] == null ? null : Mobile.fromJson(json["mobile"]),
);
Map<String, dynamic> toJson() => {
"device_id": deviceId == null ? null : deviceId,
"public_id": publicId == null ? null : publicId,
"company_id": companyId == null ? null : companyId,
"company": company == null ? null : company,
"label": label == null ? null : label,
"mobile_provider_id": mobileProviderId == null ? null : mobileProviderId,
"mobile_provider": mobileProvider == null ? null : mobileProvider,
"hologram_device_id": hologramDeviceId == null ? null : hologramDeviceId,
"hologram_link_id": hologramLinkId == null ? null : hologramLinkId,
"firmware_version_id": firmwareVersionId == null ? null : firmwareVersionId,
"version": version == null ? null : version,
"formatted_version": formattedVersion == null ? null : formattedVersion,
"device_type_id": deviceTypeId == null ? null : deviceTypeId,
"device_type": deviceType == null ? null : deviceType,
"ip_address": ipAddress == null ? null : ipAddress,
"record_interval": recordInterval == null ? null : recordInterval,
"upload_interval": uploadInterval == null ? null : uploadInterval,
"power_mode": powerMode == null ? null : powerMode,
"connectivity": connectivity == null ? null : connectivity,
"connectivity_class": connectivityClass == null ? null : connectivityClass,
"users_last_record_date": usersLastRecordDate == null ? null : usersLastRecordDate,
"gmt_last_record_date": gmtLastRecordDate == null ? null : gmtLastRecordDate?.toIso8601String(),
"battery": battery == null ? null : battery,
"battery_percentage": batteryPercentage == null ? null : batteryPercentage,
"battery_class": batteryClass == null ? null : batteryClass,
"battery_icon": batteryIcon == null ? null : batteryIcon,
"signal_quality": signalQuality == null ? null : signalQuality,
"signal_quality_class": signalQualityClass == null ? null : signalQualityClass,
"signal_quality_text": signalQualityText == null ? null : signalQualityText,
"signal_quality_icon": signalQualityIcon == null ? null : signalQualityIcon,
"queued_records": queuedRecords == null ? null : queuedRecords,
"command": command == null ? null : command,
"status": status == null ? null : status,
"status_class": statusClass == null ? null : statusClass,
"purchase_date": purchaseDate == null ? null : "${purchaseDate?.year.toString().padLeft(4, '0')}-${purchaseDate?.month.toString().padLeft(2, '0')}-${purchaseDate?.day.toString().padLeft(2, '0')}",
"warranty_period": warrantyPeriod == null ? null : warrantyPeriod,
"warranty_expires": warrantyExpires == null ? null : "${warrantyExpires?.year.toString().padLeft(4, '0')}-${warrantyExpires?.month.toString().padLeft(2, '0')}-${warrantyExpires?.day.toString().padLeft(2, '0')}",
"warranty_status": warrantyStatus == null ? null : warrantyStatus,
"temperature_class": temperatureClass == null ? null : temperatureClass,
"temperature_metric": temperatureMetric == null ? null : temperatureMetric,
"temperature_imperial": temperatureImperial == null ? null : temperatureImperial,
"surge_protection": surgeProtection == null ? null : surgeProtection,
"total_products": totalProducts == null ? null : totalProducts,
"temperature_low_threshold": temperatureLowThreshold,
"temperature_high_threshold": temperatureHighThreshold,
"notes": notes,
"import_id": importId,
"deleted": deleted == null ? null : deleted,
"created_by": createdBy == null ? null : createdBy,
"last_updated_by": lastUpdatedBy == null ? null : lastUpdatedBy,
"deleted_by": deletedBy,
"date_created": dateCreated,
"date_modified": dateModified == null ? null : dateModified,
"date_deleted": dateDeleted,
"scope": scope == null ? null : scope,
"owner": owner == null ? null : owner,
"links": links == null ? null : links!.toJson(),
"ports": ports == null ? null : List<dynamic>.from(ports!.map((x) => x.toJson())),
"iot_device_tags": iotDeviceTags == null ? null : List<dynamic>.from(iotDeviceTags!.map((x) => x.toJson())),
"entity_addresses": entityAddresses == null ? null : List<dynamic>.from(entityAddresses!.map((x) => x.toJson())),
"available_ports": availablePorts == null ? null : List<dynamic>.from(availablePorts!.map((x) => x)),
"mobile": mobile == null ? null : mobile?.toJson(),
};
}
class EntityAddress {
EntityAddress({
required this.entityAddressesId,
required this.objectRef,
required this.objectId,
required this.address1,
required this.address2,
required this.city,
required this.state,
required this.zipCode,
required this.zipCodeExt,
required this.countryName,
required this.countryIso2,
required this.countryIso3,
required this.countryId,
required this.fullSingleLineAddress,
required this.fullMultiLineAddress,
required this.addressType,
required this.prime,
required this.primeType,
required this.primeClass,
required this.mapsLink,
required this.deleted,
required this.createdBy,
required this.lastUpdatedBy,
required this.deletedBy,
required this.dateCreated,
required this.dateModified,
@required this.dateDeleted,
@required this.links,
});
final String entityAddressesId;
final String objectRef;
final String objectId;
final String address1;
final String address2;
final String city;
final String state;
final String zipCode;
final dynamic zipCodeExt;
final String countryName;
final String countryIso2;
final String countryIso3;
final String countryId;
final String fullSingleLineAddress;
final String fullMultiLineAddress;
final String addressType;
final String prime;
final String primeType;
final String primeClass;
final String mapsLink;
final String deleted;
final String createdBy;
final String lastUpdatedBy;
final dynamic deletedBy;
final String dateCreated;
final String dateModified;
final dynamic dateDeleted;
final EntityAddressLinks? links;
factory EntityAddress.fromJson(Map<String, dynamic> json) => EntityAddress(
entityAddressesId: json["entity_addresses_id"] == null ? null : json["entity_addresses_id"],
objectRef: json["object_ref"] == null ? null : json["object_ref"],
objectId: json["object_id"] == null ? null : json["object_id"],
address1: json["address1"] == null ? null : json["address1"],
address2: json["address2"] == null ? null : json["address2"],
city: json["city"] == null ? null : json["city"],
state: json["state"] == null ? null : json["state"],
zipCode: json["zip_code"] == null ? null : json["zip_code"],
zipCodeExt: json["zip_code_ext"],
countryName: json["country_name"] == null ? null : json["country_name"],
countryIso2: json["country_iso_2"] == null ? null : json["country_iso_2"],
countryIso3: json["country_iso_3"] == null ? null : json["country_iso_3"],
countryId: json["country_id"] == null ? null : json["country_id"],
fullSingleLineAddress: json["full_single_line_address"] == null ? null : json["full_single_line_address"],
fullMultiLineAddress: json["full_multi_line_address"] == null ? null : json["full_multi_line_address"],
addressType: json["address_type"] == null ? null : json["address_type"],
prime: json["prime"] == null ? null : json["prime"],
primeType: json["prime_type"] == null ? null : json["prime_type"],
primeClass: json["prime_class"] == null ? null : json["prime_class"],
mapsLink: json["maps_link"] == null ? null : json["maps_link"],
deleted: json["deleted"] == null ? null : json["deleted"],
createdBy: json["created_by"] == null ? null : json["created_by"],
lastUpdatedBy: json["last_updated_by"] == null ? null : json["last_updated_by"],
deletedBy: json["deleted_by"],
dateCreated: json["date_created"] == null ? null : json["date_created"],
dateModified: json["date_modified"] == null ? null : json["date_modified"],
dateDeleted: json["date_deleted"],
links: json["links"] == null ? null : EntityAddressLinks.fromJson(json["links"]),
);
Map<String, dynamic> toJson() => {
"entity_addresses_id": entityAddressesId == null ? null : entityAddressesId,
"object_ref": objectRef == null ? null : objectRef,
"object_id": objectId == null ? null : objectId,
"address1": address1 == null ? null : address1,
"address2": address2 == null ? null : address2,
"city": city == null ? null : city,
"state": state == null ? null : state,
"zip_code": zipCode == null ? null : zipCode,
"zip_code_ext": zipCodeExt,
"country_name": countryName == null ? null : countryName,
"country_iso_2": countryIso2 == null ? null : countryIso2,
"country_iso_3": countryIso3 == null ? null : countryIso3,
"country_id": countryId == null ? null : countryId,
"full_single_line_address": fullSingleLineAddress == null ? null : fullSingleLineAddress,
"full_multi_line_address": fullMultiLineAddress == null ? null : fullMultiLineAddress,
"address_type": addressType == null ? null : addressType,
"prime": prime == null ? null : prime,
"prime_type": primeType == null ? null : primeType,
"prime_class": primeClass == null ? null : primeClass,
"maps_link": mapsLink == null ? null : mapsLink,
"deleted": deleted == null ? null : deleted,
"created_by": createdBy == null ? null : createdBy,
"last_updated_by": lastUpdatedBy == null ? null : lastUpdatedBy,
"deleted_by": deletedBy,
"date_created": dateCreated == null ? null : dateCreated,
"date_modified": dateModified == null ? null : dateModified,
"date_deleted": dateDeleted,
"links": links == null ? null : links?.toJson(),
};
}
class EntityAddressLinks {
EntityAddressLinks({
required this.self,
});
final String self;
factory EntityAddressLinks.fromJson(Map<String, dynamic> json) => EntityAddressLinks(
self: json["self"] == null ? null : json["self"],
);
Map<String, dynamic> toJson() => {
"self": self == null ? null : self,
};
}
class IotDeviceTag {
IotDeviceTag({
required this.id,
required this.deviceId,
required this.tagId,
required this.tag,
required this.companyId,
required this.createdBy,
required this.lastUpdatedBy,
required this.deletedBy,
required this.dateCreated,
required this.dateModified,
required this.dateDeleted,
required this.scope,
required this.owner,
required this.links,
});
final String id;
final String deviceId;
final String tagId;
final String tag;
final String companyId;
final String createdBy;
final dynamic lastUpdatedBy;
final dynamic deletedBy;
final String dateCreated;
final dynamic dateModified;
final dynamic dateDeleted;
final String scope;
final String owner;
final EntityAddressLinks? links;
factory IotDeviceTag.fromJson(Map<String, dynamic> json) => IotDeviceTag(
id: json["id"] == null ? null : json["id"],
deviceId: json["device_id"] == null ? null : json["device_id"],
tagId: json["tag_id"] == null ? null : json["tag_id"],
tag: json["tag"] == null ? null : json["tag"],
companyId: json["company_id"] == null ? null : json["company_id"],
createdBy: json["created_by"] == null ? null : json["created_by"],
lastUpdatedBy: json["last_updated_by"],
deletedBy: json["deleted_by"],
dateCreated: json["date_created"] == null ? null : json["date_created"],
dateModified: json["date_modified"],
dateDeleted: json["date_deleted"],
scope: json["scope"] == null ? null : json["scope"],
owner: json["owner"] == null ? null : json["owner"],
links: json["links"] == null ? null : EntityAddressLinks.fromJson(json["links"]),
);
Map<String, dynamic> toJson() => {
"id": id == null ? null : id,
"device_id": deviceId == null ? null : deviceId,
"tag_id": tagId == null ? null : tagId,
"tag": tag == null ? null : tag,
"company_id": companyId == null ? null : companyId,
"created_by": createdBy == null ? null : createdBy,
"last_updated_by": lastUpdatedBy,
"deleted_by": deletedBy,
"date_created": dateCreated == null ? null : dateCreated,
"date_modified": dateModified,
"date_deleted": dateDeleted,
"scope": scope == null ? null : scope,
"owner": owner == null ? null : owner,
"links": links == null ? null : links?.toJson(),
};
}
class DeviceLinks {
DeviceLinks({
required this.self,
required this.customer,
});
final String self;
final String customer;
factory DeviceLinks.fromJson(Map<String, dynamic> json) => DeviceLinks(
self: json["self"] == null ? null : json["self"],
customer: json["customer"] == null ? null : json["customer"],
);
Map<String, dynamic> toJson() => {
"self": self == null ? null : self,
"customer": customer == null ? null : customer,
};
}
这是我进行 api 调用的地方：
import 'dart:convert';
import 'package:gateway_device/models/device_model.dart';
import 'package:gateway_device/models/devices_list_model.dart';
import 'package:gateway_device/utils/app_constants.dart';
import 'package:http/http.dart' as http;
import 'package:shared_preferences/shared_preferences.dart';
class ApiService {
Future getSingleDevice(int id) async {
final singleDeviceUrl = Uri.parse(AppConstants.BASE_URL +
AppConstants.DEVICE_LIST_URI +
'/' +
id.toString());
print(singleDeviceUrl);
final response = await http.get(singleDeviceUrl, headers: {
'Authorization': 'Bearer ' + AppConstants.TOKEN,
'X-API-KEY': AppConstants.API_KEY
});
if (response.statusCode == 200) {
// print(response.body);
// print(json);
var body = json.decode(response.body);
print(body);
return DeviceClass.fromJson(body);
} else {
// print(response.statusCode);
// print(response.body);
print("no data");
}
}
}
这里要注意的有趣的事情是，当我 print(body); 时我得到的东西看起来像我想要的。
这是我尝试使用数据的地方：
import 'package:flutter/material.dart';
import 'package:gateway_device/backend/api/api_services.dart';
import 'package:gateway_device/models/device_model.dart';
import 'dart:convert';
class DeviceProfileWidget extends StatelessWidget {
final int id;
const DeviceProfileWidget({Key? key, required this.id}) : super(key: key);
@override
Widget build(BuildContext context) {
return Scaffold(
backgroundColor: Colors.white,
body: FutureBuilder(
future: ApiService().getSingleDevice(id),
builder: (context, AsyncSnapshot snapshot) {
if (snapshot.hasData) {
DeviceClass device = snapshot.data;
print(device);
return Scaffold(
body: Container(
margin: EdgeInsets.only(top: 125,left: 125),
child: Row(
children: [
Text(device.deviceId)
],
),
),
);
}
return const Center(child: CircularProgressIndicator());
}));
}
}
这里需要注意的有趣的事情是，当我尝试打印（设备）时，我得到了 DeviceClass 的实例。如果我尝试打印（device.deviceId）或任何其他包含数据的字段（显然它们应该基于我之前的屏幕截图），我会得到空值。
为了澄清，如果需要，我尝试在将设备分配给 snapshot.data 之后、返回脚手架之前打印 device 和 device.deviceId。
我已经为此工作了相当长一段时间，但我陷入困境、沮丧，需要帮助。
提前致谢。
你的问题是你的类没有覆盖toString()属于类的方法Object. The toString()方法被自动调用print()以及要求将对象表示为文本的其他场景。此方法的默认实现只是打印创建对象的类的名称。
如果您只想使用它进行调试，最简单的可能就是调用toJson()调用时的方法toString() on Device。所以像这样：
class Device {
Device({
required this.device,
});
final DeviceClass? device;
factory Device.fromJson(Map<String, dynamic> json) => Device(
device: json["device"] == null ? null : DeviceClass.fromJson(json["device"]),
);
Map<String, dynamic> toJson() => {
"device": device == null ? null : device?.toJson(),
};
// Start: Added method
@override
String toString() => toJson().toString();
// End: Added method
}
但是您可以自由地在您的中生成另一个字符串toString() method.