json - 我厌倦了在颤抖中找出我的产品列表长度。你能帮我找出我的问题吗？

问题描述

我收到NoSuchMethodError：在 null 上调用了 getter 'length'。接收方：空。尝试在此结构上调用：长度错误。
基本上我试图从 json 文件中找出产品列表并打印产品的长度。它给出了正确的响应，但是当我尝试通过 fromjson 方法将 json 转换为 dart 时，我遇到了上述问题。我通过在线 dart 到 json 转换器制作了我的模型类。所以你能帮我找出我的问题吗？这是我的存储库部分。

Future<List<Products>> getProducts() async {
final response = await http.post(AppStrings.productsListUrl,
    body: {"store_uid": "demotest", "APIKey": "test03"});
if (response.statusCode == 200) {
  print("success!!!!!");
  var data = json.decode(response.body);
 List<Products> products = Data.fromJson(data).products;
 print(products.length);
  return products;
} else {
  print("Error");
  throw Exception();
}}

这是我的模型课

class ApiResultModel {
  String status;
  int code;
  Data data;
  List<String> message;

  ApiResultModel({this.status, this.code, this.data, this.message});

  ApiResultModel.fromJson(Map<String, dynamic> json) {
    status = json['status'];
    code = json['code'];
    data = json['data'] != null ? new Data.fromJson(json['data']) : null;
    message = json['message'].cast<String>();
  }

  Map<String, dynamic> toJson() {
    final Map<String, dynamic> data = new Map<String, dynamic>();
    data['status'] = this.status;
    data['code'] = this.code;
    if (this.data != null) {
      data['data'] = this.data.toJson();
    }
    data['message'] = this.message;
    return data;
  }
}

class Data {
  Paginator paginator;
  int paginationLastPage;
  List<Products> products;

  Data({this.paginator, this.paginationLastPage, this.products});

  Data.fromJson(Map<String, dynamic> json) {
    paginator = json['paginator'] != null
        ? new Paginator.fromJson(json['paginator'])
        : null;
    paginationLastPage = json['pagination_last_page'];
    if (json['products'] != null) {
      products = new List<Products>();
      json['products'].forEach((v) {
        products.add(new Products.fromJson(v));
      });
    }
  }

  Map<String, dynamic> toJson() {
    final Map<String, dynamic> data = new Map<String, dynamic>();
    if (this.paginator != null) {
      data['paginator'] = this.paginator.toJson();
    }
    data['pagination_last_page'] = this.paginationLastPage;
    if (this.products != null) {
      data['products'] = this.products.map((v) => v.toJson()).toList();
    }
    return data;
  }
}

class Paginator {
  int currentPage;
  int totalPages;
  Null previousPageUrl;
  String nextPageUrl;
  int recordPerPage;

  Paginator(
      {this.currentPage,
        this.totalPages,
        this.previousPageUrl,
        this.nextPageUrl,
        this.recordPerPage});

  Paginator.fromJson(Map<String, dynamic> json) {
    currentPage = json['current_page'];
    totalPages = json['total_pages'];
    previousPageUrl = json['previous_page_url'];
    nextPageUrl = json['next_page_url'];
    recordPerPage = json['record_per_page'];
  }

  Map<String, dynamic> toJson() {
    final Map<String, dynamic> data = new Map<String, dynamic>();
    data['current_page'] = this.currentPage;
    data['total_pages'] = this.totalPages;
    data['previous_page_url'] = this.previousPageUrl;
    data['next_page_url'] = this.nextPageUrl;
    data['record_per_page'] = this.recordPerPage;
    return data;
  }
}

class Products {
  String productName;
  String productSku;
  String productSkuCode;
  String checkoutRefCode;
  String productDescription;
  int price;
  int priceInclTax;
  String productThumbImage;
  int productTypeId;
  int isActive;
  int isStockable;
  int priceExclTax;
  String storeName;
  BrandInfo brandInfo;

  Products(
      {this.productName,
        this.productSku,
        this.productSkuCode,
        this.checkoutRefCode,
        this.productDescription,
        this.price,
        this.priceInclTax,
        this.productThumbImage,
        this.productTypeId,
        this.isActive,
        this.isStockable,
        this.priceExclTax,
        this.storeName,
        this.brandInfo});

  Products.fromJson(Map<String, dynamic> json) {
    productName = json['product_name'];
    productSku = json['product_sku'];
    productSkuCode = json['product_sku_code'];
    checkoutRefCode = json['checkout_ref_code'];
    productDescription = json['product_description'];
    price = json['price'];
    priceInclTax = json['price_incl_tax'];
    productThumbImage = json['product_thumb_image'];
    productTypeId = json['product_type_id'];
    isActive = json['is_active'];
    isStockable = json['is_stockable'];
    priceExclTax = json['price_excl_tax'];
    storeName = json['store_name'];
    brandInfo = json['brand_info'] != null
        ? new BrandInfo.fromJson(json['brand_info'])
        : null;
  }

  Map<String, dynamic> toJson() {
    final Map<String, dynamic> data = new Map<String, dynamic>();
    data['product_name'] = this.productName;
    data['product_sku'] = this.productSku;
    data['product_sku_code'] = this.productSkuCode;
    data['checkout_ref_code'] = this.checkoutRefCode;
    data['product_description'] = this.productDescription;
    data['price'] = this.price;
    data['price_incl_tax'] = this.priceInclTax;
    data['product_thumb_image'] = this.productThumbImage;
    data['product_type_id'] = this.productTypeId;
    data['is_active'] = this.isActive;
    data['is_stockable'] = this.isStockable;
    data['price_excl_tax'] = this.priceExclTax;
    data['store_name'] = this.storeName;
    if (this.brandInfo != null) {
      data['brand_info'] = this.brandInfo.toJson();
    }
    return data;
  }
}

class BrandInfo {
  int id;
  String brandName;
  String brandCode;
  int isActive;
  String brandLogo;
  String brandUid;
  String storeUid;

  BrandInfo(
      {this.id,
        this.brandName,
        this.brandCode,
        this.isActive,
        this.brandLogo,
        this.brandUid,
        this.storeUid});

  BrandInfo.fromJson(Map<String, dynamic> json) {
    id = json['id'];
    brandName = json['brand_name'];
    brandCode = json['brand_code'];
    isActive = json['is_active'];
    brandLogo = json['brand_logo'];
    brandUid = json['brand_uid'];
    storeUid = json['store_uid'];
  }

  Map<String, dynamic> toJson() {
    final Map<String, dynamic> data = new Map<String, dynamic>();
    data['id'] = this.id;
    data['brand_name'] = this.brandName;
    data['brand_code'] = this.brandCode;
    data['is_active'] = this.isActive;
    data['brand_logo'] = this.brandLogo;
    data['brand_uid'] = this.brandUid;
    data['store_uid'] = this.storeUid;
    return data;
  }
}

标签： jsonflutterdart

json - 我厌倦了在颤抖中找出我的产品列表长度。你能帮我找出我的问题吗？

问题描述

解决方案

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