Hi, I've been trying to set the "photoImageView.image" to the image "cell.bgImage" within the collectionView indexPath based on the selection. With a tap on the collectionView's image cells, I want the photoImageView.image to change according to the tapped image cell. I have tried many ways but couldn't get success. I believe the most feasible way is implementing this in "collectionView didSelectItemAt". Any help please ?Thank you.import Foundationimport UIKitimport Photosclass PhotoViewController: UIViewController { @IBOutlet weak var photoImageView: UIImageView! @IBOutlet var photoView: UIView! @IBOutlet weak var menuStackView: UIStackView! var imagePicker = UIImagePickerController() var effects = Effects() override func viewDidLoad() { super.viewDidLoad() imagePicker.delegate = self assignTap() view.addSubview(collectionView) collectionView.backgroundColor = .white collectionView.topAnchor.constraint(equalTo: photoImageView.bottomAnchor, constant: 110).isActive = true collectionView.leadingAnchor.constraint(equalTo: view.leadingAnchor, constant: 10).isActive = true collectionView.trailingAnchor.constraint(equalTo: view.trailingAnchor, constant: 10).isActive = true collectionView.bottomAnchor.constraint(equalTo: view.bottomAnchor, constant: -103).isActive = true collectionView.clipsToBounds = true collectionView.dataSource = self collectionView.delegate = self collectionView.isHidden = false } @IBAction func previewTapped(_ sender: UIButton) { sender.pulsate() if collectionView.isHidden == true { collectionView.isHidden = false } else { collectionView.isHidden = true } } @IBAction func effectsTapped(_ sender: UIButton) { sender.flash() } @IBAction func exportTapped(_ sender: UIButton) { sender.shake() } func assignTap() { let tap = UITapGestureRecognizer(target: self, action: #selector(touchTapped(_:))) photoView.addGestureRecognizer(tap) } @objc func touchTapped(_ sender: UITapGestureRecognizer) { if collectionView.isTracking == false { if menuStackView.isHidden == false { collectionView.isHidden = true menuStackView.isHidden = true } else { menuStackView.isHidden = false collectionView.isHidden = false } } } func chooseImage(_ sender: Any) { if UIImagePickerController.isSourceTypeAvailable(.photoLibrary) { imagePicker.sourceType = .photoLibrary imagePicker.allowsEditing = true self.present(imagePicker,animated: true, completion: nil) } } func accessVideo(_ sender: Any) { if UIImagePickerController.isSourceTypeAvailable(.camera) { imagePicker.sourceType = .camera self.present(imagePicker, animated: true, completion: nil) } else { print("Camera not available") } } public func chooseLastImage(_ sender: Any) { print("photoImageView", photoImageView!) print("photoImageView.bounds", photoImageView.bounds) let targetSize: CGSize? = CGSize(width: photoImageView.bounds.width, height: photoImageView.bounds.height) let options = PHImageRequestOptions() options.isNetworkAccessAllowed = true options.deliveryMode = .highQualityFormat let imgManager = PHImageManager.default() let fetchOptions = PHFetchOptions() fetchOptions.sortDescriptors = [NSSortDescriptor(key:"creationDate", ascending: true)] let fetchResult: PHFetchResult = PHAsset.fetchAssets(with: .image, options: fetchOptions) print("targetSize for request", targetSize!) imgManager.requestImage(for: fetchResult.lastObject!, targetSize: targetSize!, contentMode: .default, options: options) { (result, info) in guard let result = result else { return } DispatchQueue.main.async(execute: { self.photoImageView.image = result self.collectionView.reloadData() }) } } fileprivate let collectionView: UICollectionView = { let layout = UICollectionViewFlowLayout() layout.scrollDirection = .horizontal let cv = UICollectionView(frame: .zero, collectionViewLayout: layout) cv.translatesAutoresizingMaskIntoConstraints = false cv.register(CustomCell.self, forCellWithReuseIdentifier: "PreviewCell") return cv }()}extension PhotoViewController: UICollectionViewDelegateFlowLayout, UICollectionViewDataSource { func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, sizeForItemAt indexPath: IndexPath) -> CGSize { return CGSize(width: collectionView.frame.width/5, height: collectionView.frame.width/4) } func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int { return 11 } func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell { let cell = collectionView.dequeueReusableCell(withReuseIdentifier: "PreviewCell", for: indexPath) as! CustomCell cell.bgImage = self.photoImageView.image if indexPath.row == 0 { cell.labelText = "A" } if indexPath.row == 1 { cell.labelText = "B" guard cell.bgImage != nil else { return cell } cell.bgImage = effects.applyFilterTo(image: photoImageView.image!, filterEffect: Effects.Filter(filterName: "CIPhotoEffectChrome", filterEffectValue: nil, filterEffectValueName: nil)) } if indexPath.row == 2 { cell.labelText = "C" guard cell.bgImage != nil else { return cell } cell.bgImage = effects.applyFilterTo(image: photoImageView.image!, filterEffect: Effects.Filter(filterName: "CIPhotoEffectInstant", filterEffectValue: nil, filterEffectValueName: nil)) } if indexPath.row == 3 { cell.labelText = "D" guard cell.bgImage != nil else { return cell } cell.bgImage = effects.applyFilterTo(image: photoImageView.image!, filterEffect: Effects.Filter(filterName: "CIPhotoEffectNoir", filterEffectValue: nil, filterEffectValueName: kCIInputImageKey)) } if indexPath.row == 4 { cell.labelText = "E" guard cell.bgImage != nil else { return cell } cell.bgImage = effects.applyFilterTo(image: photoImageView.image!, filterEffect: Effects.Filter(filterName: "CIPhotoEffectMono", filterEffectValue: nil, filterEffectValueName: kCIInputImageKey)) } if indexPath.row == 5 { cell.labelText = "F" guard cell.bgImage != nil else { return cell } cell.bgImage = effects.applyFilterTo(image: photoImageView.image!, filterEffect: Effects.Filter(filterName: "CIExposureAdjust", filterEffectValue: 1, filterEffectValueName: kCIInputEVKey)) } if indexPath.row == 6 { cell.labelText = "G" guard cell.bgImage != nil else { return cell } cell.bgImage = effects.applyFilterTo(image: photoImageView.image!, filterEffect: Effects.Filter(filterName: "CISRGBToneCurveToLinear", filterEffectValue: nil, filterEffectValueName: nil)) } if indexPath.row == 7 { cell.labelText = "H" guard cell.bgImage != nil else { return cell } cell.bgImage = effects.applyFilterTo(image: photoImageView.image!, filterEffect: Effects.Filter(filterName: "CIPhotoEffectTransfer", filterEffectValue: nil, filterEffectValueName: nil)) } if indexPath.row == 8 { cell.labelText = "I" guard cell.bgImage != nil else { return cell } cell.bgImage = effects.applyFilterTo(image: photoImageView.image!, filterEffect: Effects.Filter(filterName: "CIColorPosterize", filterEffectValue: nil, filterEffectValueName: nil)) } if indexPath.row == 9 { cell.labelText = "J" guard cell.bgImage != nil else { return cell } cell.bgImage = effects.applyFilterTo(image: photoImageView.image!, filterEffect: Effects.Filter(filterName: "CIPhotoEffectProcess", filterEffectValue: nil, filterEffectValueName: nil)) } if indexPath.row == 10 { cell.labelText = "K" guard cell.bgImage != nil else { return cell } cell.bgImage = effects.applyFilterTo(image: photoImageView.image!, filterEffect: Effects.Filter(filterName: "CIVignetteEffect", filterEffectValue: nil, filterEffectValueName: nil)) } return cell } func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, insetForSectionAt section: Int) -> UIEdgeInsets { return UIEdgeInsets(top: 10, left: 5, bottom: 10, right: 5) } func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, minimumInteritemSpacingForSectionAt section: Int) -> CGFloat { return 1 } func collectionView(_ collectionView: UICollectionView, didSelectItemAt indexPath: IndexPath) { let cell = collectionView.dequeueReusableCell(withReuseIdentifier: "PreviewCell", for: indexPath) as! CustomCell // cell.bgImage = self.photoImageView.image let imgArr = [cell.bgImage] photoImageView.image = imgArr[indexPath.row] photoImageView.reloadInputViews() }}class CustomCell: UICollectionViewCell { fileprivate let bg: UIImageView = { let iv = UIImageView() iv.translatesAutoresizingMaskIntoConstraints = false iv.contentMode = .scaleAspectFit iv.clipsToBounds = true return iv }() var bgImage: UIImage? { get { bg.image } set { bg.image = newValue } } fileprivate let label: UILabel = { let il = UILabel(frame: CGRect(x: 0, y: 0, width: 100, height: 20)) il.translatesAutoresizingMaskIntoConstraints = false il.contentMode = .scaleAspectFit il.clipsToBounds = true return il }() var labelText: String? { // #### get { label.text } set { label.text = newValue } } override init(frame: CGRect) { super.init(frame: frame) contentView.addSubview(bg) contentView.addSubview(label) bg.topAnchor.constraint(equalTo: contentView.topAnchor).isActive = true bg.leadingAnchor.constraint(equalTo: contentView.leadingAnchor).isActive = true bg.trailingAnchor.constraint(equalTo: contentView.trailingAnchor).isActive = true bg.bottomAnchor.constraint(equalTo: contentView.bottomAnchor).isActive = true label.bottomAnchor.constraint(equalTo: contentView.bottomAnchor).isActive = true } required init?(coder: NSCoder) { fatalError("init(coder:) has not been implemented") }}extension PhotoViewController: UIImagePickerControllerDelegate, UINavigationControllerDelegate { func imagePickerController(_ picker: UIImagePickerController, didFinishPickingMediaWithInfo info: [UIImagePickerController.InfoKey : Any]) { if let image = info[UIImagePickerController.InfoKey.originalImage] as? UIImage { photoImageView.image = image } dismiss(animated: true, completion: nil) } func imagePickerControllerDidCancel(_ picker: UIImagePickerController) { dismiss(animated: true, completion: nil) }}