prevent picking the same photo twice in UIImagePickerController - ios

Question

How do i prevent users from picking the same image twice in UIImagePickerContoroller to avoid duplication?
I tried doing it with the URLReference but its not working so I'm guessing its not the way.
func imagePickerController(_ picker: UIImagePickerController, didFinishPickingMediaWithInfo info: [String : Any]) {
if let url = info[UIImagePickerControllerReferenceURL] as? NSURL{
if photosURL.contains(url){
Utilities.showMessage(message: "photo Uploaded already", sender: self, title: ErrorTitle.FRIENDS, onDismissAction: nil)
} else {
if let pickedImage = info[UIImagePickerControllerOriginalImage] as? UIImage {
photos.append(pickedImage)
}
}
}
dismiss(animated: true, completion: nil)
}
thanks,

Answer 1

You should also consider doing the picker.dismiss first and do the other logic with the image afterward. That way, you can prevent the user from tapping an image multiple times and invoking the delegate function several times.
func imagePickerController(_ picker: UIImagePickerController, didFinishPickingMediaWithInfo info: [UIImagePickerController.InfoKey : Any]) {
guard !picker.isBeingDismissed else {
return
}
picker.dismiss(animated: true) {
if let pickedImage = (info[UIImagePickerController.InfoKey(rawValue: UIImagePickerController.InfoKey.originalImage.rawValue)] as? UIImage) {
// do stuff with the picked image
print("Uesr picked an image \(pickedImage)")
}
}
}

Answer 2

swift 4
func imagePickerController(_ picker: UIImagePickerController, didFinishPickingMediaWithInfo info: [UIImagePickerController.InfoKey : Any]) {
let info = convertFromUIImagePickerControllerInfoKeyDictionary(info)
if let capturedImage = info[convertFromUIImagePickerControllerInfoKey(UIImagePickerController.InfoKey.originalImage)] as? UIImage {
// do stuff
}
picker.delegate = nil
picker.dismiss(animated: true, completion: nil)
}

Answer 3

Seems like you haven't appended the url to the photosURL?
try this out:
func imagePickerController(_ picker: UIImagePickerController, didFinishPickingMediaWithInfo info: [String : Any]) {
if let url = info[UIImagePickerControllerReferenceURL] as? NSURL{
if photosURL.contains(url){
Utilities.showMessage(message: "photo Uploaded already", sender: self, title: ErrorTitle.FRIENDS, onDismissAction: nil)
} else {
photosURL.append(url)
if let pickedImage = info[UIImagePickerControllerOriginalImage] as? UIImage {
photos.append(pickedImage)
}
}
}
dismiss(animated: true, completion: nil)
}

Answer 4

preselectedAssetIdentifiers
If you have chosen PHPicker while creating a gallery picker in an application you created with SwiftUI, and you want to prevent this picker from selecting the selected photos over and over again, you can apply the following method.
The feature that will prevent the user from selecting the same photo twice is "preselectedAssetIdentifiers"
import Foundation
import PhotosUI
import SwiftUI
struct GalleryPicker: UIViewControllerRepresentable {
func makeCoordinator() -> Coordinator {
return GalleryPicker.Coordinator(parent: self)
}
#Binding var images: [UIImage]
#Binding var picker: Bool
#Binding var preSelected: [String]
func makeUIViewController(context: Context) -> PHPickerViewController {
var configuration = PHPickerConfiguration(photoLibrary: .shared())
configuration.preselectedAssetIdentifiers = preSelected
configuration.filter = .images
configuration.selection = .ordered
configuration.selectionLimit = 0
let picker = PHPickerViewController(configuration: configuration)
picker.delegate = context.coordinator.self
return picker
}
func updateUIViewController(_ uiViewController: UIViewControllerType, context: Context) {
}
class Coordinator: NSObject, PHPickerViewControllerDelegate {
var parent: GalleryPicker
init(parent: GalleryPicker) {
self.parent = parent
}
func picker(_ picker: PHPickerViewController, didFinishPicking results: [PHPickerResult]) {
parent.picker.toggle()
for result in results {
let provider = result.itemProvider
let assetIdentifier = result.assetIdentifier ?? ""
print("asset --> \(assetIdentifier)")
if provider.canLoadObject(ofClass: UIImage.self) {
provider.loadObject(ofClass: UIImage.self) { image, _ in
DispatchQueue.main.async {
self.parent.preSelected.append(assetIdentifier)
self.parent.images.append(image as! UIImage)
}
}
}
}
}
}
}
screenshot