_CastError（类型“_InternalLinkedHashMap<String, dynamic>”不是类型转换中类型 'List<dynamic>' 的子类型）

Question

想再问...尝试实现存储在本地数据库中的数据API... JSON API 的形式对象中有一个 JSON 数组...想要从 API 加载数据到本地数据库时出错。 .. 大致这是一个错误，因为“错误的模型或什么

Api 服务

class MealApiProvider {
  Future<List<Categories>> getAllMeal() async {
    var url = "https://www.themealdb.com/api/json/v1/1/categories.php";
    Response response = await Dio().get(url);
    print("Hasil Respon ${response.data}");
    return (response.data as List).map((employee) {
      print('Inserting $employee');
      DBProvider.db.insertMeals(Categories.fromJson(employee));
    }).toList();
  }
}

型号

class DataMeal {
  final List<Categories> categories;

  DataMeal({this.categories});

  @override
  String toString() {
    return 'DataMeal{categories: $categories}';
  }

  factory DataMeal.fromJson(Map<String, dynamic> json) {
    return DataMeal(
      categories: List<Categories>.from(
        json["categories"].map(
          (categories) {
            return Categories.fromJson(categories);
          },
        ),
      ),
    );
  }

  Map<String, dynamic> toJson() => {
        "categories": List<dynamic>.from(
          categories.map(
            (x) => x.toJson(),
          ),
        ),
      };
}

本地数据库

  initDB() async {
    Directory documentsDirectory = await getApplicationDocumentsDirectory();
    final String path = join(documentsDirectory.path, '$nameDatabase');
    print('insert database $path');

    return await openDatabase(path, version: 1, onOpen: (db) {},
        onCreate: (Database db, int version) async {
      await db.execute('CREATE TABLE $nameTable('
          'idCategory,'
          'strCategory TEXT,'
          'strCategoryThumb TEXT,'
          'strCategoryDescription TEXT'
          ')');
    });
  }

  insertMeals(DataMeal newMeal) async {
    await deleteAllMeal();
    final Database db = await database;
    final res = await db.insert("$nameTable", newMeal.toJson());
    print("inserting data $res");
    return res;
  }

错误

return (response.data as List).map((employee)

Respon Data

Answer 1

您的回复开头包含地图！试试这个

class MealApiProvider {
  Future<List<Categories>> getAllMeal() async {
    var url = "https://www.themealdb.com/api/json/v1/1/categories.php";
    Response response = await Dio().get(url);
    print("Hasil Respon ${response.data}");
    //***Change below line****
    return (response.data['categories'] as List).map((employee) {
      print('Inserting $employee');
      DBProvider.db.insertMeals(Categories.fromJson(employee));
    }).toList();
  }
}

而不是

class MealApiProvider {
  Future<List<Categories>> getAllMeal() async {
    var url = "https://www.themealdb.com/api/json/v1/1/categories.php";
    Response response = await Dio().get(url);
    print("Hasil Respon ${response.data}");
    //*** I change the below line !
    return (response.data as List).map((employee) {
      print('Inserting $employee');
      DBProvider.db.insertMeals(Categories.fromJson(employee));
    }).toList();
  }
}

_CastError（类型“_InternalLinkedHashMap<String, dynamic>”不是类型转换中类型 'List<dynamic>' 的子类型）

_CastError (type '_InternalLinkedHashMap<String, dynamic>' is not a subtype of type 'List<dynamic>' in type cast)

json

flutter

dart

sharedpreferences

sqflite