Swift 中的 Alamofire 和 ObjectMapper 到 TableView

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

Answer 2

You are missing the main object. Add this class in addition to your Device class.

import Foundation
import ObjectMapper

class Response: Mappable {

    required init?(map: Map) {
    }

    func mapping(map: Map) {
        success<-map["success"]
        user_id<-map["user_id"]
        devices<-map["devices"]
    }

    var success : Bool?
    var user_id : String?
    var devices: [Device]?

}

Also create a new variable to map the main object

var response: Response?

and change

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

to

self.response = Mapper<Response>().map(JSONString: json.rawString()!)
self.devices = self.response.devices