Alamofire and ObjectMapper to TableView in Swift

Question

I am new to swift and trying to fetch json from an api and show it to UITableView but it won't show.

This is the json:

{
    "success": true,
    "user_id": "somestringhere",
    "devices": [
        {
            "id": "somestringhere",
            "source": "somestringhere",
            "source_text": "somestringhere",
            "logo_url": "somestringhere",
            "is_connected": "0"
        },
        {

For mapping the json data:

import Foundation
import ObjectMapper

class Devices: Mappable {
required init?(map: Map) {
}

    func mapping(map: Map) {
        id<-map["id"]
        source<-map["source"]
        sourceText<-map["source_text"]
        logo<-map["logo_url"]
        isConnected<-map["is_connected"]  
    }
   
    var id : String?
    var source : String?
    var sourceText : String?
    var logo : String?
    var isConnected : Bool?
    
}

My Controller:

import Foundation
import UIKit
import SwiftyJSON
import Alamofire
import ObjectMapper

class HomeViewController: UIViewController, UITableViewDelegate, UITableViewDataSource {
    var devices : [Devices]?

    override func viewDidLoad() {
        super.viewDidLoad()
      
        tableView.register(HomeTableViewCell.nib(), forCellReuseIdentifier: HomeTableViewCell.identifier)
        tableView.delegate = self
        tableView.dataSource = self
        loadData()
    }
    
    func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
        return devices?.count ?? 0
    }
    func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
        let cell = tableView.dequeueReusableCell(withIdentifier: HomeTableViewCell.identifier, for: indexPath) as! HomeTableViewCell
        
        cell.setup(title: "\(devices?[indexPath.row].sourceText)", iconLink: "\(devices?[indexPath.row].logo)")
        return cell
    }
    func tableView(_ tableView: UITableView, heightForRowAt indexPath: IndexPath) -> CGFloat {
        return 120
    }
    
    func loadData(){
        let base = Config().base
        let endPoint = Config.EndPoint()
        let patientId = User().id
            
                let url = base + endPoint.showDevices
                let header: HTTPHeaders = [
                    "Content-Type": "application/json",
                ]
                let params: Parameters = [
                    "patient_id" : patientId
                ]
                
                let code = Code(id: id)
                AF.request(url, method: .get, parameters: params, encoding: URLEncoding.default, headers:header).validate()
                    .response{ (response) in
                        switch response.result {
                        case .success(let value):
                            let json = JSON(value)
                           
                          self.devices = Mapper<Devices>().mapArray(JSONString: json.rawString()!)
            self.tableView.reloadData()
                           
                         case .failure(let error):
                            print(error)
  }
 }    
}
}

I tried printing the device variable after the Mapper

self.devices = Mapper<PatientDevices>().mapArray(JSONString: json.rawString()!)
print(self.devices)

and shows me

Optional([ProjectName.Devices])

I tried to print json response data and request successful however I couldn't add it to tableview. What should I do to solve this problem? I don't know what I am doing wrong.

Answer 1

First of all – as always – since Swift 4 libraries like ObjectMapper and SwiftyJSON have become obsolete in favor of built-in, efficient Codable protocol. Avoid tutorials which suggest those outdated libraries.

Regarding your mistake you are ignoring the root object, the object with keys success, user_id and devices.

This is a solution using Decodable

• Drop SwiftyJSON and ObjectMapper

• Replace the structs with

    struct Root : Decodable {
        let success : Bool
        let userId : String
        let devices : [Device]
    }
  
    struct Device : Decodable {
        let id : String
        let source : String
        let sourceText : String
        let logoUrl : URL
        let isConnected : String // this value is String, not Bool
    }
  

• Replace loadData with

    func loadData(){
        let base = Config().base
        let endPoint = Config.EndPoint()
        let patientId = User().id
  
        let url = base + endPoint.showDevices
        let header: HTTPHeaders = [
            "Content-Type": "application/json",
        ]
        let params: Parameters = [
            "patient_id" : patientId
        ]
  
        let code = Code(id: id)
        AF.request(url, parameters: params, headers:header).validate()
            .responseData { (response) in
                switch response.result {
                    case .success(let data):
                        do {
                            let decoder = JSONDecoder()
                            decoder.keyDecodingStrategy = .convertFromSnakeCase
                            let result = try decoder.decode(Root.self, from: data)
                            self.devices = result.devices
                            self.tableView.reloadData()
                        } catch { print(error) }
  
                    case .failure(let error):
                        print(error)
                }
        }
    }
  

  The Alamofire response returns raw data and the keyDecodingStrategy converts the snake_cased keys to camelCased struct members and logoUrl is decoded as URL

• Finally rename the data source array to

    var devices = [Device]()
  

  and remove all question marks after devices