type'(dynamic)=>Category'不是'transform'Flutter型別'(String,dynamic)=>Map

因此，我嘗試使用 API，并且不斷收到此錯誤型別 '(dynamic) => Category' is not a subtype of type '(String, dynamic) => MapEntry<dynamic, dynamic>' of 'transform'

這是我的類別模型

import 'dart:convert';    

List<Category> categoryFromJson(String str) =>
        List<Category>.from(json.decode(str).map((x) => Category.fromJson(x))); // I get the error here
    
    String categoryToJson(List<Category> data) =>
        json.encode(List<dynamic>.from(data.map((x) => x.toJson())));
    
    class Category {
      Category({
        required this.id,
        required this.name,
        required this.icon,
      });
    
      int id;
      String name;
      String icon;
    
      factory Category.fromJson(Map<String, dynamic> json) => Category(
            id: json["id"],
            name: json["name"],
            icon: json["icon"],
          );
    
      Map<String, dynamic> toJson() => {
            "id": id,
            "name": name,
            "icon": icon,
          };
    }

這是我的類別存盤庫。更像服務

import 'package:elibrary/services/requests.dart';
import 'package:elibrary/services/endpoints.dart';
import 'package:get/get.dart';

class CategoryRepository extends GetxService {
  ApiClient apiClient = ApiClient();

  Future<Response> getCategories() async {
    return await apiClient.getRequest(ProjectConstants.CATEGORY_URI);
  }
}

這是類別控制器

import 'dart:io';

import 'package:elibrary/model/categories.dart';
import 'package:elibrary/services/repository/category_repository.dart';
import 'package:flutter/material.dart';
import 'package:get/get.dart';

class CategoryController extends GetxController {
  CategoryRepository categoryRepository = CategoryRepository();

  RxList<Category> categoryList = <Category>[].obs;
  RxBool isLoading = false.obs;

  @override
  void onInit() {
    super.onInit();
    getCategoryList();
  }

  Future<void> getCategoryList() async {
    isLoading(true);
    try {
      Response categoryResponse = await categoryRepository.getCategories();
      if (categoryResponse.statusCode == 200) {
        categoryList.assignAll(
          categoryFromJson(categoryResponse.bodyString ?? ''),
        );
      } else {
        debugPrint(categoryResponse.bodyString ?? '');
        debugPrint(
          categoryResponse.statusText.toString(),
        );
      }
    } on SocketException {
      GetSnackBar(
        message: "No Internet Connectivity",
        duration: Duration(seconds: 5),
      ).show();
    } catch (e) {
      debugPrint(
        e.toString(),
      );
    } finally {
      isLoading(false);
    }
  }

  SnackbarController showErrorMessage(
      Response<dynamic> categoryResponse, String message) {
    return Get.snackbar(
      "Error Occurred",
      categoryResponse.statusText.toString(),
      snackPosition: SnackPosition.BOTTOM,
      colorText: Colors.white,
      backgroundColor: Colors.red,
    );
  }
}

我嘗試通過這種方式在回圈中使用

通過改變這個

List<Category> categoryFromJson(String str) => List<Category>.from(json.decode(str).map((x) => Category.fromJson(x)));

對此

List<Category> categoryFromJson(String str) => [
      for (Map<String, dynamic> x in json.decode(str)) Category.fromJson(x),
    ];

但它給了我這個錯誤

type '_InternalLinkedHashMap<String, dynamic>' is not a subtype of type 'Iterable<dynamic>'

我已閱讀此未處理的例外

我也讀過這個發生例外

我再次有這也顫抖_TypeError

uj5u.com熱心網友回復：

嘗試這個：

List<Category> categoryFromJson(String str) => (json.decode(str)["data"] as List<Map<String, dynamic>>).map((x) => Category.fromJson(x)).toList();

或者如果你想要 for 回圈格式：

List<Category> categoryFromJson(String str) => [
      for (Map<String, dynamic> x in json.decode(str)["data"]) Category.fromJson(x),
    ];

uj5u.com熱心網友回復：

嘗試更改以下代碼行

List<Category> categoryFromJson(String str) => List<Category>.from(json.decode(str).map((x) => Category.fromJson(x)));

to（添加 toList() 到地圖閉包）

List<Category> categoryFromJson(String str) => List<Category>.from(json.decode(str).map((x) => Category.fromJson(x)).toList());

標籤：扑api镖

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