Populate tableview with multiple Alamofire chained requests - ios

Question

I am new at Alamofire and I am following the book IOS Apps with REST APIs, where I try to parse JSON and populate the tableview but the problem is that it calls numberOfRowsInSection before the function loadGists finishes calling the Alamofire chained requests so I can populate the Array and then populate the tableview accordingly, it seems that .responseArray function is called Asynchronous or called after numberOfRowsInSection function.
var gists: [Gist]!
#IBOutlet var tabelView1: UITableView!
override func viewDidLoad() {
super.viewDidLoad()
self.tabelView1.delegate = self
self.tabelView1.dataSource = self
}
override func viewDidAppear(animated: Bool) {
super.viewDidAppear(animated)
loadGists()
}
func loadGists() {
GitHubAPIManager.sharedInstance.getPublicGists() { result in
guard result.error == nil else {
print(result.error)
// TODO: display error
return
}
if let fetchedGists = result.value {
self.gists = fetchedGists
}
DispatchQueue.main.async {
self.tableView1.reloadData()
}
}
}
Where GitHubAPIManager Class has:
class GitHubAPIManager: NSObject {
static let sharedInstance = GitHubAPIManager()
func getPublicGists(completionHandler: (Result<[Gist]>) -> Void) {
Alamofire.request(GistRouter.GetPublic())
.responseArray { (response) in
completionHandler(response.result)
}
}
}
And responseArray is:
public func responseArray<T: ResponseJSONObjectSerializable>(
completionHandler: Response<[T]) -> Self {
let serializer = ResponseSerializer<[T]> { request, response, data, error in
guard error == nil else {
return .Failure(error!)
}
guard let responseData = data else {
let failureReason = "Array could not be serialized because input data was nil."
let error = Error.errorWithCode(.DataSerializationFailed,
failureReason: failureReason)
return .Failure(error)
}
let JSONResponseSerializer = Request.JSONResponseSerializer(options: .AllowFragments)
let result = JSONResponseSerializer.serializeResponse(request, response,
responseData, error)
switch result {
case .Success(let value):
let json = SwiftyJSON.JSON(value)
var objects: [T] = []
for (_, item) in json {
if let object = T(json: item) {
objects.append(object)
}
}
return .Success(objects)
case .Failure(let error):
return .Failure(error)
}
}
return response(responseSerializer: serializer, completionHandler: completionHandler)
}
For table view:
func tableView(tableView: UITableView,
numberOfRowsInSection section: Int) -> Int {
return gists.count
}
func tableView(tableView: UITableView, cellForRowAtIndexPath
indexPath: NSIndexPath) -> UITableViewCell {
let cell = tableView.dequeueReusableCellWithIdentifier("Cell", forIndexPath: indexPath)
let gist = gists[indexPath.row]
cell.textLabel!.text = gist.description
cell.detailTextLabel!.text = gist.ownerLogin
return cell
}
GistRouter is:
enum GistRouter: URLRequestConvertible {
static let baseURLString:String = "https://api.github.com"
case getPublic()
var method: HTTPMethod {
switch self {
case .getPublic:
return .get
}
}
func asURLRequest() throws -> URLRequest {
let result: (path: String, parameters: [String: AnyObject]?) = {
switch self {
case .getPublic:
return ("/gists/public", nil)
}
}()
let URL = Foundation.URL(string: GistRouter.baseURLString)!
var UrlRequest: URLRequest? = URLRequest(url: URL.appendingPathComponent(result.path))
UrlRequest = try URLEncoding.default.encode(UrlRequest!, with: result.parameters)
UrlRequest?.httpMethod = method.rawValue
return UrlRequest!
}
And Gist Class is:
class Gist: ResponseJSONObjectSerializable {
var id: String?
var description: String?
var ownerLogin: String?
var ownerAvatarURL: String?
var url: String?
required init(json: SwiftyJSON.JSON) {
self.description = json["description"].string
self.id = json["id"].string
self.ownerLogin = json["owner"]["login"].string
self.ownerAvatarURL = json["owner"]["avatar_url"].string
self.url = json["url"].string
}
required init() {
}
}
I have tried DispatchQueue.global(qos: .utility).async and also
let semaphore = DispatchSemaphore(value: 0) in different ways with no luck, I need to have Alamofire chained requests all done first and then numberOfRowsInSection called, please help.

Answer 1

It worked for me with:
var gists = [Gist]() {
didSet {
self.tabelView1.reloadData()
}
}