Delay in Updating UILabel from API call - swift

Question

I am updating my UILabels from an API Call. I have an API Client file which pulls the needed information and then passes it over to the DataStore and then parses through the information and then creates movie Objects. The collectionViewController accesses the information without a problem but when it passes the information to the next view controller, a problem occurs. The information does not appear on the view controller and then when I click back in the information will appear. There is some sort of delay in the information from the API Client or something which I can't seem to figure out.
//Second API call to get information for the Second View Controller (Detail View Controller)
class func getDescriptiveMovieResultsFromSearch(movieID: String, completion:(NSDictionary)-> ())
{
var descriptiveDictionary: [String: String] = [:]
let searchURL = "https://www.omdbapi.com/?i=\(movieID)&?plot=short"
let nsurl = NSURL(string: searchURL)
//convert the url into an NSURL
guard let unwrappedNSURL = nsurl else {print("ERROR OCCURRED HERE"); return}
//unwrap the nsurl using guard let
//let session = NSURLSession.sharedSession()
let request = NSMutableURLRequest(URL: unwrappedNSURL)
//creation of the request
request.HTTPMethod = "GET"
//By Default everythiing is a GET request if you are getting information and you don't need it
//request has an HTTPMethod of type "GET" to obtain information
let task = NSURLSession.sharedSession().dataTaskWithRequest(request) { (data, response, error) in
guard let unwrappedData = data else {print("Error occurred here"); return}
if let responseDictionary = try? NSJSONSerialization.JSONObjectWithData(unwrappedData, options: []) as? NSDictionary
{
let castedResponseDictionary = responseDictionary as? [String : String]
guard let unwrappedResponseDictionary = castedResponseDictionary else {print("This did not work!"); return}
descriptiveDictionary = unwrappedResponseDictionary
}
completion(descriptiveDictionary)
}
task.resume()
}
//MovieDataStore function to parse through the information
/Second API Call
func getDescriptiveMovieInformationWith(movie: Movie, Completion: (Bool) -> ())
{
guard let unwrappedimdbID = movie.imdbID else {print("AN ERROR OCCURRED HERE"); return}
OMDBAPIClient.getDescriptiveMovieResultsFromSearch(unwrappedimdbID) { (descriptiveResponseDictionary) in
let desMovieDirector = descriptiveResponseDictionary["Director"] as? String
let desMovieWriters = descriptiveResponseDictionary["Writer"] as? String
let desMovieActors = descriptiveResponseDictionary["Actors"] as? String
let desMovieShortPlot = descriptiveResponseDictionary["Plot"] as? String
let desMovieimbdRating = descriptiveResponseDictionary["imdbRating"] as? String
//unwrapping each of the of the json information
guard let
unwrappedDesMovieDirector = desMovieDirector,
unwrappedDesMovieWriters = desMovieWriters,
unwrappedDesMovieActors = desMovieActors,
unwrappedDesMovieShortPlot = desMovieShortPlot,
unwrappedDesMovieimbdRating = desMovieimbdRating
else {print("AN ERROR OCCURRED HERE!"); return}
movie.director = unwrappedDesMovieDirector
movie.writers = unwrappedDesMovieWriters
movie.actors = unwrappedDesMovieActors
movie.shortPlot = unwrappedDesMovieShortPlot
movie.imdbRating = unwrappedDesMovieimbdRating
print("******************************************")
print("Movie Director: \(movie.director)")
print("Movie writers: \(movie.writers)")
print("Movie actors: \(movie.actors)")
print("Movie shortPlot: \(movie.shortPlot)")
print("Movie imdbRating: \(movie.imdbRating)")
print("******************************************")
//Completion(true)
Completion(true)
}
}
//Detail View Controller
/Second API Call
func getDescriptiveMovieInformationWith(movie: Movie, Completion: (Bool) -> ())
{
guard let unwrappedimdbID = movie.imdbID else {print("AN ERROR OCCURRED HERE"); return}
OMDBAPIClient.getDescriptiveMovieResultsFromSearch(unwrappedimdbID) { (descriptiveResponseDictionary) in
let desMovieDirector = descriptiveResponseDictionary["Director"] as? String
let desMovieWriters = descriptiveResponseDictionary["Writer"] as? String
let desMovieActors = descriptiveResponseDictionary["Actors"] as? String
let desMovieShortPlot = descriptiveResponseDictionary["Plot"] as? String
let desMovieimbdRating = descriptiveResponseDictionary["imdbRating"] as? String
//unwrapping each of the of the json information
guard let
unwrappedDesMovieDirector = desMovieDirector,
unwrappedDesMovieWriters = desMovieWriters,
unwrappedDesMovieActors = desMovieActors,
unwrappedDesMovieShortPlot = desMovieShortPlot,
unwrappedDesMovieimbdRating = desMovieimbdRating
else {print("AN ERROR OCCURRED HERE!"); return}
movie.director = unwrappedDesMovieDirector
movie.writers = unwrappedDesMovieWriters
movie.actors = unwrappedDesMovieActors
movie.shortPlot = unwrappedDesMovieShortPlot
movie.imdbRating = unwrappedDesMovieimbdRating
print("******************************************")
print("Movie Director: \(movie.director)")
print("Movie writers: \(movie.writers)")
print("Movie actors: \(movie.actors)")
print("Movie shortPlot: \(movie.shortPlot)")
print("Movie imdbRating: \(movie.imdbRating)")
print("******************************************")
//Completion(true)
Completion(true)
}
}
//detail view Controller
override func viewDidLoad() {
super.viewDidLoad()
self.view.backgroundColor = UIColor.blackColor()
self.titleLabel.textColor = UIColor.yellowColor()
self.yearLabel.textColor = UIColor.yellowColor()
self.directorLabel.textColor = UIColor.yellowColor()
self.writersLabel.textColor = UIColor.yellowColor()
self.actorsLabel.textColor = UIColor.yellowColor()
self.shortPlotLabel.textColor = UIColor.yellowColor()
self.imdbIDLabel.textColor = UIColor.yellowColor()
self.typeLabel.textColor = UIColor.yellowColor()
self.imdbRating.textColor = UIColor.yellowColor()
stackViewLabel.translatesAutoresizingMaskIntoConstraints = false
stackViewLabel.topAnchor.constraintEqualToAnchor(self.topImage.bottomAnchor, constant: 5).active = true
stackViewLabel.widthAnchor.constraintEqualToAnchor(self.view.widthAnchor, multiplier: 1.00).active = true
stackViewLabel.heightAnchor.constraintEqualToAnchor(self.view.heightAnchor, multiplier: 0.50).active = true
stackViewLabel.leftAnchor.constraintEqualToAnchor(self.view.leftAnchor).active = true
//unwrapped Movie Object
guard let unwrappedMovieObject = movieObject else {print("AN ERROR OCCURRED HERE!"); return}
self.store.getDescriptiveMovieInformationWith(unwrappedMovieObject) { (isWorking) in
if isWorking {
dispatch_async(dispatch_get_main_queue()){
guard let unwrappedPosterURL = unwrappedMovieObject.posterURL else {print("AN ERROR OCCURRED HERE"); return}
if unwrappedPosterURL == "N/A"{
self.topImage.image = UIImage.init(named: "star_PNG1592")
}
else {
if let url = NSURL(string: unwrappedPosterURL){
if let data = NSData(contentsOfURL: url){
//print("I have an image to display")
self.topImage.image = UIImage.init(data: data)
}
}
}
self.titleLabel.text = unwrappedMovieObject.title
self.yearLabel.text = unwrappedMovieObject.year
self.imdbIDLabel.text = unwrappedMovieObject.imdbID
self.typeLabel.text = unwrappedMovieObject.type
guard let
unwrappedDirector = unwrappedMovieObject.director,
unwrappedWriters = unwrappedMovieObject.writers,
unwrappedActors = unwrappedMovieObject.actors,
unwrappedShortPlot = unwrappedMovieObject.shortPlot,
unwrappedRating = unwrappedMovieObject.imdbRating
else {print("PROPERTIES WERE UNWRAPPED"); return}
self.directorLabel.text = unwrappedDirector
self.writersLabel.text = unwrappedWriters
self.actorsLabel.text = unwrappedActors
self.shortPlotLabel.text = unwrappedShortPlot
self.imdbRating.text = unwrappedRating
}
}
else{
print("AN ERROR OCCURRED HERE")
}
}
}

Answer 1

NSURLSession.sharedSession().dataTaskWithRequest(request)
I'm not sure what callback queue the sharedSession uses, If its not the main thread you will need to
DispatchQueue.main.async {
completion(descriptiveDictionary)
}