在 Swift 中将 NSArray 转换为数组会生成 nil 到数组值

Question

我遇到了一个我认为很简单的问题，但不知何故我想不出任何解决方法。它只是将 NSArray 转换为数组，我认为我在这里用这段代码做得很好：

func getTrainingSubCategories(completion: @escaping(Result<[TrainingSubCategory], GetError>) -> Void){
let dataTask = URLSession.shared.dataTask(with: resourceURL){data, _, _ in
guard let jsonData = data else {
completion(.failure(.trainingCategoriesNoDataAvailable))
return
}
do{
let parsedData = try JSONSerialization.jsonObject(with: jsonData) as! [String: Any]
for (key, value) in parsedData {
if key == "categories" {
if let categoriesDictionary: [[String: Any]] = value as? [[String: Any]]{
for categoryDictionary in categoriesDictionary{
for (key, value) in categoryDictionary{
if key == "sub_categories" {
print("1st Type => (type(of: value)) Value => (value)")
print("2nd Type => (type(of: value as? Array<TrainingSubCategory>)) Value => (value as? Array<TrainingSubCategory>)")
//                                        guard let subCategoryValue = value as? Array<TrainingSubCategory> else{
//                                            fatalError("Error in casting value to array of trainingsubcategory")
//                                        }
}
}
}
}
}
}
}catch {
completion(.failure(.trainingSubCategoriesCannotProcessData))
}
}
dataTask.resume()
}

但控制台会以其他方式记录：

1st Value => (
{
"category_id" = 1;
"company_id" = 50;
"created_at" = "2019-11-07 00:58:37";
"deleted_at" = "<null>";
id = 1;
name = Advertisement;
"updated_at" = "2019-11-07 00:58:37";
},
{
"category_id" = 1;
"company_id" = 50;
"created_at" = "<null>";
"deleted_at" = "<null>";
id = 3;
name = Sales;
"updated_at" = "2019-11-10 23:28:30";
}
)
2nd Value => nil
1st Value => (
{
"category_id" = 2;
"company_id" = 50;
"created_at" = "2019-11-07 19:58:07";
"deleted_at" = "<null>";
id = 6;
name = Inventory;
"updated_at" = "2019-11-07 19:58:07";
}
)
2nd Value => nil
1st Value => (
{
"category_id" = 3;
"company_id" = 50;
"created_at" = "2019-11-10 21:24:22";
"deleted_at" = "<null>";
id = 9;
name = "Human Resource";
"updated_at" = "2019-11-10 21:24:22";
}
)
2nd Value => nil

我在这里错过了什么吗？我对 Swift 很陌生，所以我自己其实没有太多猜测。

Answer 1

所以我使返回类型只是一个 NSDictionary 数组。

func getTrainingSubCategories(completion: @escaping(Result<[NSDictionary], GetError>) -> Void){
let dataTask = URLSession.shared.dataTask(with: resourceURL){data, _, _ in
guard let jsonData = data else {
completion(.failure(.trainingCategoriesNoDataAvailable))
return
}
var trainingSubCategories = [NSDictionary]()
do{
let parsedData = try JSONSerialization.jsonObject(with: jsonData) as! [String: Any]
for (key, value) in parsedData {
if key == "categories" {
if let categoriesDictionary: [[String: Any]] = value as? [[String: Any]]{
for categoryDictionary in categoriesDictionary{
for (key, value) in categoryDictionary{
if key == "sub_categories" {
if let subCategoriesArray: [Any] = value as? [Any] {
for subCategory in subCategoriesArray{
trainingSubCategories.append(subCategory as! NSDictionary)
}
}
}
}
}
}
}
completion(.success(trainingSubCategories))
}
}catch {
completion(.failure(.trainingSubCategoriesCannotProcessData))
}

}
dataTask.resume()
}

我的函数调用和返回如下所示：

private func downloadSubCategories(withCompanyID: Int) {
let trainingCategoriesRequest = GetRequests(endpoint: "getTrainingCategories", id: String(withCompanyID))
trainingCategoriesRequest.getTrainingSubCategories{result in
switch result{
case .success(let trainingSubCategories):
for counter in 0 ..< trainingSubCategories.count {
for (key, value) in trainingSubCategories[counter]{
print("(key) => (value)")
}
}
case .failure(let error):
print(error)
}
}
}

我能够在不将NSDictionary转换为TrainingSubCategory的情况下映射它们。很抱歉，我会查看这篇文章，这不是对最初问题的答案，而是一种解决方法。:)