使用 Swift 解析 tableview 中的 JSON

Question

我是解析 JSON 的新手。我做了一个单一视图应用程序。我使用此函数从 URL 获取 JSON：

func parseData(){
        //created URL
        guard let requestURL = URL(string: "https://machla.bh/api-category2") else {return }
        
        //creating URLRequest
        var request = URLRequest(url: requestURL)
        
        //setting the method to post
        request.httpMethod = "POST"
        
        //creating the post parameter by concatenating the keys and values from text field
        var postParameters = ""
        
        postParameters += "key=LpfyirxoNOfP8wPns4nZqTw6DQ4wY A2q6yvpKsof6gkYDTykVXSEonTO2VB HE2zRdqrvsyoyMVyRagWtKAtVuOuNs c7QW5KrgbXS8SqPZ7sIDlPEvhBWyo5 NoObAcor3GlO87nRSaFdxhKDRTiBkK 3pFsTQyffzuBdIBiM8zFra6Yh8NbbC QQaratgFFE2hzLouNEIHq88xaSqum1 C0z7g325i3hixT5oLSo5tvhpvvdTJO WohfqGSakeGz7hsAU"
        
        postParameters += "&path=59"
        
        postParameters += "&language_id=1"
        
        //adding the parameters to request body
        request.httpBody = postParameters.data(using: .utf8)
        
        //creating a task to send the post request
        let session = URLSession.shared
        
        let task = session.dataTask(with: request) { data, response, error in
            
            guard error == nil else {
                print("error is \(error!.localizedDescription)")
                return
            }
            guard let data = data else {
                print("No data was returned by the request!")
                return
            }
            
            
            // print data from request
            let str = String(data: data, encoding: .utf8)!
              print(str)
            for eachFetechedCountry in str
            {
                let eachCountry=eachFetechedCountry as! [String:Any]
                let category = eachCountry["categories"] as! String
                let product=eachCountry["products"] as! String
                self.fetchcountry.append(Country(categories: category, products: product))
                
            }
            self.countryTableView.reloadData()
          
        }
        
        //executing the task
        task.resume()
        
  }

我正在尝试使用上述函数中的以下语句从 JSON 读取类别和产品。这些声明不起作用。如何从 JSON 读取类别和产品？

 for eachFetechedCountry in str
                {
                    let eachCountry=eachFetechedCountry as! [String:Any]
                    let category = eachCountry["categories"] as! String
                    let product=eachCountry["products"] as! String
                    self.fetchcountry.append(Country(categories: category, products: product))
                    
                }

为了将类别和产品填充到表视图中，我创建了一个名为

Country

:

的类

class Country{

    var product:String
    var category:String
    
    init(categories :String, products:String)
    {
        self.category=categories
        self.product=products
    }
    
}

为了将类别和产品填充到表格视图中，我编码：

func tableView(_ tableViewr: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
        let cell = countryTableView.dequeueReusableCell(withIdentifier: "cell")
        cell?.textLabel?.text=fetchcountry[indexPath.row].category
        cell?.detailTextLabel?.text=fetchcountry[indexPath.row].product
        return cell!
        
    }

如何将类别和产品填充到表格视图中？

从此链接您可以下载示例项目进行修正？https://drive.google.com/file/d/0B5pNDpbvZ8SnY3RicXpGN1FYbXc/view?usp=sharing

Answer 1

您应该使用 Swift 4 的功能 - 可解码协议。

    let task = session.dataTask(with: request) { data, response, error in

       guard error == nil else {
          print("error is \(error!.localizedDescription)")
          return
       }

       guard let data = data else {
          print("No data was returned by the request!")
          return
       }

       do {
          let country = try JSONDecoder().decode(Country.self, from: data)

          // do what you want here with Country array
          // ...

       } catch let error {
          // catch error and handled it here
       }

       DispatchQueue.main.async {
          self.countryTableView.reloadData()
       }
   }

   //executing the task
   task.resume()

始终在主线程中更新表格视图！！！

并使用这些结构：

struct Country: Decodable{
    var categories: [Category]
}  

struct Category: Decodable {
    var name: String
    var products: [Product]
}

struct Product: Decodable {
    var name: String
}