ImageView inside of ScrollView showing wrong picture - arrays

Question

I have a scroll view that has an image view embedded into it. The user clicks the "Take Photo" button, takes a picture, and then those photos are stored in an array and then displayed on the scrollable imageView. My issue is that after the didFinishSelectingMedia is called and the camera closes, the imageView always shows the first image in the array. I want the imageView to show the most recent image added to the array and scroll backward through the images until the user comes to the first image in the array. How do I make this happen?
Btw: Idk if this is even plausible, but I tried reversing the for loop and that didn't work.
I'm a new programmer, so please explain your answers.
Here's my code:
import UIKit
class ViewController: UIViewController, UINavigationControllerDelegate, UIImagePickerControllerDelegate {
#IBOutlet weak var scrollImageView: UIScrollView!
var imageTaken: [UIImage] = []
var imagePicker = UIImagePickerController()
override func viewDidLoad() {
super.viewDidLoad()
scrollImageView.frame = scrollImageView.frame
}
#IBAction func takePhotoButton(_ sender: Any) {
imagePicker = UIImagePickerController()
imagePicker.delegate = self
imagePicker.sourceType = .camera
present(imagePicker, animated: true, completion: nil)
}
func imagePickerController(_ picker: UIImagePickerController, didFinishPickingMediaWithInfo info: [UIImagePickerController.InfoKey : Any]) {
imageTaken.append((info[.originalImage] as? UIImage)!)
imagePicker.dismiss(animated: true, completion: nil)
for i in 0..<imageTaken.count {
let imageView = UIImageView()
imageView.image = imageTaken[i]
imageView.contentMode = .scaleAspectFit
let xPosition = self.scrollImageView.frame.width * CGFloat(i)
imageView.frame = CGRect(x: xPosition, y: 0, width: self.scrollImageView.frame.width, height: self.scrollImageView.frame.height)
scrollImageView.contentSize.width = scrollImageView.frame.width * CGFloat(i + 1)
scrollImageView.addSubview(imageView)
}
}
}

Answer 1

Two options I guess you can take which ever one is seems easier.
OOP — Create an array of objects example:
struct TakePhotos {
var image : UIImage
var timestamp : Date
}
Then sort the array by the timestamp.
Use PHAsset
import Photos
Using PHAsset you should be able to retrieve the images taken from the user's album. Set a count when the user takes a new image.
Then you can run a query and sort the images in reverse order, they will already have the timestamp.
let photoOptions = PHFetchOptions()
photoOptions.sortDescriptors = [NSSortDescriptor(key: "creationDate", ascending: false)]
This is what I did in my application.
// FIXME: - Query only happens once this needs to be refactored so it happens when the album is updated on the device.
// Query only happens one time.
if imageArray.isEmpty {
let photoOptions = PHFetchOptions()
photoOptions.sortDescriptors = [NSSortDescriptor(key: "creationDate", ascending: false)]
let allPhotos = PHAsset.fetchAssets(with: photoOptions)
let fetchOptions = PHImageRequestOptions()
fetchOptions.deliveryMode = .highQualityFormat
fetchOptions.resizeMode = .exact
fetchOptions.normalizedCropRect = CGRect(x: 0, y: 0, width: view.frame.width, height: view.frame.width)
// Must be a synchronous call otherwise the view loads before images are retrieved (result is an empty view).
fetchOptions.isSynchronous = true
let imageSize : CGSize = CGSize(width: view.frame.width, height: view.frame.height)
//Retrieves Images using assets.
allPhotos.enumerateObjects { (assets, index, pointer) in
DispatchQueue.global(qos: .background).sync {
PHImageManager.default().requestImage(for: assets, targetSize: imageSize, contentMode: .aspectFit, options: fetchOptions) { (image, hashDictionary) in
guard let image = image else {return}
self.imageArray.append(image)
self.albumImages.append(ImageAlbum(images: image))
}
}
}
selectedImage.image = imageArray.first
selectedImage.contentMode = .scaleAspectFill
}