如何處理空的JSON物件？

我正在使用一個在應用程式啟動時回傳空串列的 API。它在 particuler 行中顯示以下錯誤： productList: List<ProductList>.from(json["ProductList"].map((x) => ProductList.fromJson(x))),

我該如何處理這個錯誤？我看到了一些解決方案，他們提供了一個空串列 []。如果你只是告訴我我應該在這里使用什么語法來處理這種錯誤......

對于此錯誤，我的應用程式有時會無限加載。

我的模型類

import 'package:meta/meta.dart';
import 'dart:convert';

MyCartItemListModel myCartItemListModelFromJson(String str) =>
    MyCartItemListModel.fromJson(json.decode(str));

String myCartItemListModelToJson(MyCartItemListModel data) =>
    json.encode(data.toJson());

class MyCartItemListModel {
  MyCartItemListModel({
    required this.status,
    required this.message,
    required this.userId,
    required this.cookieVal,
    required this.totalItem,
    required this.cartProductTotal,
    required this.shippingCharge,
    required this.cartTotal,
    required this.productList,
  });

  int status;
  String message;
  String userId;
  String cookieVal;
  String totalItem;
  String cartProductTotal;
  String shippingCharge;
  String cartTotal;
  List<ProductList> productList;

  factory MyCartItemListModel.fromJson(Map<String, dynamic> json) =>
      MyCartItemListModel(
        status: json["Status"],
        message: json["Message"],
        userId: json["UserId"] ??"",
        cookieVal: json["CookieVal"],
        totalItem: json["TotalItem"],
        cartProductTotal: json["CartProductTotal"],
        shippingCharge: json["ShippingCharge"],
        cartTotal: json["CartTotal"],
        productList: List<ProductList>.from(json["ProductList"].map((x) => ProductList.fromJson(x))),
      );

  Map<String, dynamic> toJson() => {
        "Status": status,
        "Message": message,
        "UserId": userId,
        "CookieVal": cookieVal,
        "TotalItem": totalItem,
        "CartProductTotal": cartProductTotal,
        "ShippingCharge": shippingCharge,
        "CartTotal": cartTotal,
        "ProductList": List<dynamic>.from(productList.map((x) => x.toJson())),
      };
}

class ProductList {
  ProductList({
    required this.cartId,
    required this.productId,
    required this.productName,
    required this.productImage,
    required this.productSize,
    required this.productColor,
    required this.productRate,
    required this.quantity,
    required this.productTotal,
  });

  String cartId;
  String productId;
  String productName;
  String productImage;
  String productSize;
  String productColor;
  String productRate;
  String quantity;
  String productTotal;

  factory ProductList.fromJson(Map<String, dynamic> json) => ProductList(
        cartId: json["CartId"],
        productId: json["ProductId"],
        productName: json["ProductName"],
        productImage: json["ProductImage"],
        productSize: json["ProductSize"],
        productColor: json["ProductColor"],
        productRate: json["ProductRate"],
        quantity: json["Quantity"],
        productTotal: json["ProductTotal"],
      );

  Map<String, dynamic> toJson() => {
        "CartId": cartId,
        "ProductId": productId,
        "ProductName": productName,
        "ProductImage": productImage,
        "ProductSize": productSize,
        "ProductColor": productColor,
        "ProductRate": productRate,
        "Quantity": quantity,
        "ProductTotal": productTotal,
      };
}

我的 json 回應：

   {
    "Status": 1,
    "Message": "",
    "UserId": "2",
    "CookieVal": "",
    "TotalItem": "4",
    "CartProductTotal": "1767",
    "ShippingCharge": "50",
    "CartTotal": "1817",
    "ProductList": [
        {
            "CartId": "450",
            "ProductId": "10622",
            "ProductName": "     Kids Baby Leggings Pink",
            "ProductImage": "https://sleepkart.co.in/productimage/zb9diak47ocm0q957itf_1.jpg",
            "ProductSize": "L",
            "ProductColor": "#fdc291",
            "ProductRate": "190",
            "Quantity": "1",
            "ProductTotal": "190"
        },
        {
            "CartId": "449",
            "ProductId": "10623",
            "ProductName": "Kids Baby Leggings Green",
            "ProductImage": "https://sleepkart.co.in/productimage/ogr137q1kjr9fiqwdipd_1.jpg",
            "ProductSize": "L",
            "ProductColor": "#42d19a",
            "ProductRate": "193",
            "Quantity": "1",
            "ProductTotal": "193"
        },
        {
            "CartId": "438",
            "ProductId": "10661",
            "ProductName": "Night Suit for Women",
            "ProductImage": "https://sleepkart.co.in/productimage/4jcrpnqw655vg7yoyvun_1.jpg",
            "ProductSize": "L",
            "ProductColor": "#f2be02",
            "ProductRate": "975",
            "Quantity": "1",
            "ProductTotal": "975"
        },
        {
            "CartId": "437",
            "ProductId": "10575",
            "ProductName": "Men's Navy Blue Bermuda",
            "ProductImage": "https://sleepkart.co.in/productimage/zn8oqvspajuks9u1pre4_1.jpg",
            "ProductSize": "FREE",
            "ProductColor": "#0c1155",
            "ProductRate": "409",
            "Quantity": "1",
            "ProductTotal": "409"
        }
    ]
}

uj5u.com熱心網友回復：

你可以這樣檢查：

      productList: json["ProductList"] == null ? [] :
      List<ProductList>.from(json["ProductList"].map((x)
      =>ProductList.fromJson(x)

標籤：json 扑 接口 http 镖

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