我正在通过API调用更新我的UILabels。我有一个API客户端文件，它提取所需的信息，然后将其传递给DataStore，然后解析信息，然后创建电影对象。 collectionViewController可以毫无问题地访问信息，但是当它将信息传递给下一个视图控制器时，就会出现问题。信息不会出现在视图控制器上，然后当我单击后面的信息时会出现。来自API客户端的信息存在某种延迟，或者我似乎无法弄清楚。
//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)
}
}
//详细视图控制器 覆盖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")
}
}
}
答案 0 :(得分：0)
NSURLSession.sharedSession().dataTaskWithRequest(request)
我不确定sharedSession使用什么回调队列，如果它不是你需要的主线程
DispatchQueue.main.async {
completion(descriptiveDictionary)
}