访问 NSDictionary 的数组对象中的第二级数组

Question

我正在尝试NSDictionary 的数组对象中的第二级数组，但它返回 nil

我首先定义了NSDictionary，然后访问了第一级数组，直到现在一切都很好。

let dict = JSON(responseObject as! NSDictionary)
let arrayData = dict["data"].arrayObject! as NSArray
print("arrayData", arrayData)

打印arrayData 时，我得到以下返回

data =     (
{
categories = (
    {
    categories = "<null>";
    "category_id" = 333;
    image = "https://www.example.com/images/1.jpg";
    name = "Sub Category One";
    "parent_id" = 1000;
    },
    {
    categories = "<null>";
    "category_id" = 444;
    image = "https://www.example.com/images/2.jpg";
    name = "Sub Category Two";
    "parent_id" = 1000;
    },
    {
    categories = "<null>";
    "category_id" = 555;
    image = "https://www.example.com/images/3.jpg";
    name = "Sub Category Three";
    "parent_id" = 1000;
    }
);//end of categories array
"category_id" = 1000;
image = "https://www.examples.com/images/category.jpg";
name = "Parent Category";
"parent_id" = 0;
},
)

现在我正在尝试从上面返回的数组中访问和打印categories

所以我尝试了以下方法：

if dict["categories"].arrayObject != nil{
  let arrayData2 = dict["categories"].arrayObject! as NSArray
  print("arrayData2", arrayData2)
}

我也试过了

if dict["data"]["categories"].arrayObject != nil{
  let arrayData2 = dict["data"]["categories"].arrayObject! as NSArray
  print("arrayData2", arrayData2)
}

两种方式我都获得了 nil 价值，而它应该获得真正的价值。

已编辑：在 ViewController 中添加 API 调用和 dataModel 结构

视图控制器中调用HTTPAPI函数

func callingHttppApi(){
  DispatchQueue.main.async{
    NetworkManager.sharedInstance.showLoader()
    let sessionId = self.defaults.object(forKey:"token");
    self.categoriesTableView.isUserInteractionEnabled = false

      var requstParams = [String:Any]();
      requstParams["token"] = sessionId
      NetworkManager.sharedInstance.callingHttpRequest(params:requstParams, apiname:"api/cat", cuurentView: self){success,responseObject in
        if success == 1{
          let dict = responseObject as! NSDictionary;
          if dict.object(forKey: "fault") != nil{
            let fault = dict.object(forKey: "fault") as! Bool;
            if fault == true{
              self.loginRequest()
            }
          }else{
            NetworkManager.sharedInstance.dismissLoader()
            self.view.isUserInteractionEnabled = true
            self.categoriesTableView.isUserInteractionEnabled = true
            let dict = JSON(responseObject as! NSDictionary)
            let arrayData = dict["data"].arrayObject! as NSArray
            if dict["categories"].arrayObject != nil{
              let arrayData2 = dict["categories"].arrayObject! as NSArray
              print("arrayData2", arrayData2)
            }
            print("arrayData", arrayData)
            if dict["error"].intValue == 1{
              NetworkManager.sharedInstance.showErrorMessageWithBack(view: self, message: NetworkManager.sharedInstance.language(key: "error"))
            }else{
              self.categoriesCollModel = CategoriesViewModel(data:JSON(responseObject as! NSDictionary))
              dump (self.categoriesCollModel)
            }
          }
        }else if success == 2{
          NetworkManager.sharedInstance.dismissLoader()
          self.callingHttppApi()
        }
      }
    }
  }

用于转换值的 dataModel 结构

//
//  CategoriesViewModel.swift
//

import Foundation

class Categories: NSObject{
    var id:String = ""
    var name:String = ""
    var image:String = ""

    init(data:JSON){
        self.id = data["category_id"].stringValue
        self.name  = data["name"].stringValue
        self.image = data["image"].stringValue
    }

}

class SubCategories:NSObject{
    var pid:String = ""
    var id:String = ""
    var name:String = ""
    var image:String = ""

    init(data:JSON) {
        self.pid = data["parent_id"].stringValue
        self.id = data["category_id"].stringValue
        self.name  = data["name"].stringValue
        self.image = data["image"].stringValue
    }

}

struct Categories_Data{
    var id:String = ""
    var categoriesArray = [SubCategories]()

    init(data:JSON) {
        self.id = data["category_id"].stringValue
        if let arrayData = data["data"]["categories"].arrayObject {
            categoriesArray =  arrayData.map({(value) -> SubCategories in
                return  SubCategories(data:JSON(value))
            })
        }
    }

}

class CategoriesViewModel:NSObject{
    var categoryModel = [Categories]()
    var subCategories = [SubCategories]()
  var categories_Data = [Categories_Data]()

    init(data:JSON) {

        let arrayData = data["data"].arrayObject! as NSArray
        categoryModel =  arrayData.map({(value) -> Categories in
            return  Categories(data:JSON(value))
        })

        if data["data"]["categories"].arrayObject != nil{
            let arrayData2 = data["data"]["categories"].arrayObject! as NSArray
            categories_Data =  arrayData2.map({(value) -> Categories_Data in
                return  Categories_Data(data:JSON(value))
            })
        }

        //categoryModel = Categories(data:data)


    }

    var getCategories:Array<Categories>{
        return categoryModel
    }

  var getSubCategories:Array<SubCategories>{
        return subCategories
    }

}

Answer 1

我强烈建议放弃SwiftyJSON 并使用Decodable。

CategoriesViewModel 可以简化为

struct Root: Decodable {
    let data : [Category]
}

struct Category: Decodable {
    let categories : [Category]?
    let categoryId : Int
    let image : URL
    let name : String
    let parentId : Int
}

您需要从网络请求中获取原始数据（在以下名为data 的代码中），然后您可以简单地将数据解码为结构并使用点表示法获取值。

我添加了一个辅助函数，以便能够递归地打印嵌套类别

do {
    let decoder = JSONDecoder()
    decoder.keyDecodingStrategy = .convertFromSnakeCase
    let result = try decoder.decode(Root.self, from: data)
    printCategories(result.data)
} catch { print(error) }

func printCategories(_ categories : [Category]) {
    for item in categories {
        if let subCategories = item.categories {
            printCategories(subCategories)
        }
        print(item.name, item.categoryId)
    }
}

Answer 2

您还应该在初始化模型对象时使用guard 来验证值：

init(data: JSON) {
    guard
        let id = data["category_id"] as? Int,
        let name = data["name"] as? String,
        let image = data["image"] as? String
        else {
             return
        }
    self.id = id
    self.name  = name
    self.image = image
}

请注意，id 是一个整数值，而不是字符串，因此您应该更改模型。

还可以查看Codable。

Answer 3

您以错误的方式检索对象。始终使用检查 nil 值检索对象或值...
检查以下代码以检索您的类别。

let dict = JSON(responseObject as! NSDictionary)
    if let data = dict["data"] as? Array<Any>
    {
        if let categoryArray = data["categories"] as? Array<Dictionary<String,Any>>
        {
            if categoryArray.count > 0
            {
                print(categoryArray)
            }
        }
    }

Answer 4

那么首先了解print("arrayData", arrayData)的回复。它是Dictionaries 的array。

添加时：

let arrayData = dict["data"].arrayObject! as NSArray

您将数据保存在来自dictionary 的数组中。

现在要获取您必须使用的类别arrayData：

let firstDict = arrayData[0] as! [String:Any]
let arrayData2 = firstDict["categories"] as! [[String:Any]]
print("arrayData2", arrayData2)

我添加了这段代码来显示一个数据。

更多数据可以用for循环：

for dictData in arrayData {
    let arrayData2 = dictData["categories"] as! [[String:Any]]
    print("arrayData2", arrayData2)
}

并使用此循环，您可以管理或保存相关数据。

还有一件事不要忘记添加 nil 处理部分。

在使用 swift 时还有一件事不要使用 NSArray 或 NSDictionary。

尝试使用Codable。网上有很多例子，会让你的代码更干净。

Answer 5

看起来很复杂，其实很简单，按照层次结构就行了

例如，假设您想要访问“数据 -> 类别 -> 名称”，因为在您的回复中，您可以这样做

这是包含所有内容的主词典。

if let dict = responceObject as? NSDictionary {
// now lets say you want go to your categories which is array of dictionaries

  if let arrDict = dict["categories"] as? NSArray {
      print("arrDict")

      // Now you can go anywhere in that array of dictionaries
      // For example you want to get name you can do like this

      for obj in arrDict {
         if let name = obj["name"] as? String {
            print(name)
         }
      }
  }
}

我在这里添加编辑部分

// In your webcall lets say you receive a JSON(i am naming it as "json") object with type Any
if let jsonObj = json as? [String: Any], let mainDict = jsonObj["data"] as? [[String: Any]] {
    for arr in mainDict {
       if let arrDict = arr["categories"] as? [[String: Any]] {
           print(arrDict)
           // Now you can dig that dict which is array of dictionaries
           for obj in arrDict {
              if let name = obj["name"] as? String {
                 print(name)
              }

              if let id = obj["id"] as? Int { // Int or whatever it is
                 print(id)  
              } 
           }
       }
    }
}

希望这会奏效。