Passing data from a class to same instance of a viewcontroller - ios

Question

When a specific event happens(in my case when a tab bar is changed) I want to create a new link from an Array. I have gotten this to work but the problem I am not facing is when i try to pass the generated link to the same viewcontroller i get an error
fatal error: unexpectedly found nil while unwrapping an Optional value
This happens when I try to change the UILabel movietitle and imageview. I think this is because every time it sends the link it creates a new ViewController instead of using the existing one. Might also be that i have missed an unwrapped value somewhere. Hope someone here can help me!
StringBuilder:
import UIKit
class StringBuilder: NSObject {
let urlString = "https://api.themoviedb.org/3/discover/movie?api_key=935f539acb9e5534ddeed3fb57e&language=en-US&sort_by=popularity.desc&include_adult=false&include_video=false&page=1&with_genres=12"
let urlStringMultipleGenres = "https://api.themoviedb.org/3/discover/movie?api_key=935f539acbf5534ddeed3fb57e&language=en-US&sort_by=popularity.desc&include_adult=false&include_video=false&page=1&with_genres=28,12,10749"
var currentGenreArray: Array<Int> = []
//This will be run after the user has selected or deselected genres in the genreControllerView
func updateGenres(genreArrayIn: Array<Int>){
print("update genres input: ")
print(genreArrayIn)
//If new array input is the same as old arrayinput, do nothing
if genreArrayIn == currentGenreArray{
return
}
else{
let returnedLink = generateString(genreID: genreArrayIn)
print("Returned link after generate string" + returnedLink)
sendLink(link: returnedLink)
}
}
//After the updated genres have been put into an Array, this function will generate the whole string which
//will be the main String the getMovieRequest follows
func generateString(genreID: Array<Int>) -> String{
let filteredGenreArray = filterZeroes(unfilteredArray: genreID)
currentGenreArray = genreID
print("current genre array: ")
print(currentGenreArray)
let baseString = "https://api.themoviedb.org/3/discover/movie?api_key=935f539acbfed4ddeed3fb57e&language=en-US&sort_by=popularity.desc&include_adult=false&include_video=false&page=1&with_genres="
var generatedString = baseString
for id in filteredGenreArray{
let k = String(id)
generatedString += k + ","
}
print("Generated Link from Strinbuilder: ")
print(generatedString)
return generatedString
}
func filterZeroes(unfilteredArray: Array<Int>) -> Array<Int>{
let filteredGenreArray = unfilteredArray.filter {$0 > 0}
print("filtered array: ")
print(filteredGenreArray)
return filteredGenreArray
}
func sendLink(link: String){
let storyBoard = UIStoryboard(name: "Main", bundle: nil)
let movieVC = storyBoard.instantiateViewController(withIdentifier: "movieView") as! ViewController
movieVC.getMovieData(activeGenreLink: link)
print("new link sent from sendlink()")
}
}
ViewController:
import UIKit
import Alamofire
import AlamofireImage
class ViewController: UIViewController{
static let sharedInstance = ViewController()
var movieIndex = 0
var movieArray:[Movie] = []
var downloadGrp = DispatchGroup()
#IBOutlet var uiMovieTitle: UILabel!
#IBOutlet var uiMoviePoster: UIImageView!
#IBOutlet var posterLoading: UIActivityIndicatorView!
override func viewDidLoad() {
super.viewDidLoad()
// Do any additional setup after loading the view, typically from a nib.
let firstTimeLink = "https://api.themoviedb.org/3/discover/movie?api_key=935f539acb9e5534ddeed3fb57e&language=en-US&sort_by=popularity.desc&include_adult=false&include_video=false&page=1&with_genres=35,18"
getMovieData(activeGenreLink: firstTimeLink)
let tapGestureRecognizer = UITapGestureRecognizer(target: self, action: #selector(imageTapped(tapGestureRecognizer:)))
uiMoviePoster.isUserInteractionEnabled = true
uiMoviePoster.addGestureRecognizer(tapGestureRecognizer)
print("settings Sucessful")
}
func imageTapped(tapGestureRecognizer: UITapGestureRecognizer){
performSegue(withIdentifier: "detailsSegue", sender: self)
}
#IBAction func yesBtn(_ sender: UIButton) {
movieIndex += 1
updateUI()
}
#IBAction func seenBtn(_ sender: UIButton) {
movieIndex += 1
}
#IBAction func noBtn(_ sender: UIButton) {
movieIndex += 1
}
//Get movie data
func getMovieData(activeGenreLink: String){
//self.posterLoading.startAnimating()
movieIndex = 0
self.downloadGrp.enter()
Alamofire.request(activeGenreLink).responseJSON { response in
//print(response.request) // original URL request
//print(response.response) // HTTP URL response
//print(response.data) // server data
//print(response.result) // result of response serialization
self.movieArray = []
print(self.movieArray)
if let json = response.result.value as? Dictionary<String,AnyObject> {
if let movies = json["results"] as? [AnyObject]{
for movie in movies{
let movieObject: Movie = Movie()
let title = movie["title"] as! String
let releaseDate = movie["release_date"] as! String
let posterPath = movie["poster_path"] as! String
let overView = movie["overview"] as! String
let movieId = movie["id"] as! Int
let genre_ids = movie["genre_ids"] as! [AnyObject]
movieObject.title = title
movieObject.movieRelease = releaseDate
movieObject.posterPath = posterPath
movieObject.overView = overView
movieObject.movieId = movieId
for genre in genre_ids{//Genre ids, fix this
movieObject.movieGenre.append(genre as! Int)
}
Alamofire.request("http://image.tmdb.org/t/p/w1920" + posterPath).responseImage {
response in
//print(response.request)
//print(response.response)
//debugPrint(response.result)
if var image = response.result.value {
image = UIImage(data: response.data!)!
movieObject.poster = image
}
}
self.movieArray.append(movieObject)
}//End of for each movie
}
else{
print("error while making results anyobject")
}
}
else{
print("error while trying to make NSDictionary")}
self.downloadGrp.leave()
}//End of Json request
downloadGrp.notify( queue: .main){
print("all downloads finished")
DispatchQueue.main.asyncAfter(deadline: .now() + .seconds(3)) {
print(self.movieArray[0].title!)
self.updateUI()
print("updatedUI")
}
}
}//End of getmoviedata
override func prepare(for segue: UIStoryboardSegue,sender: Any?){
// Create a variable that you want to send
let currentMovie = self.movieArray[movieIndex]
if let destinationVC = segue.destination as? DetailsViewController{
destinationVC.currentMovie = currentMovie
}
}
func updateUI(){
//self.posterLoading.stopAnimating()
if uiMoviePoster == nil{
print(uiMovieTitle.debugDescription)
}
else{
print("first time debugID: " + uiMovieTitle.debugDescription)
uiMovieTitle.text = self.movieArray[movieIndex].title
uiMoviePoster.image = self.movieArray[movieIndex].poster
}
}
}

Answer 1

You want to grab a sharedInstance not instantiate from a storyboard
let movieVC = ViewController.sharedInstance()
but I still do not understand why do you need to do it like this