Swift View Controller blank when attempting to load image from tableView - ios

Question

Bear with me as I’m a novice programmer. I'm building out a project where a user goes into their photo library, selects a photo and displays the image's name in a tableView. They can select that image in the tableView and it will then load a full size of that image.
Problem: When I click the row item in the tableView to load the image, the new view controller is just a white screen and not the image previously selected.
Here is the view controller that displays the image:
class DetailViewController: UIViewController {
var selectedImage: String?
#IBOutlet var image: UIImageView!
override func viewDidLoad() {
super.viewDidLoad()
if let imageToLoad = selectedImage {
image.image = UIImage(named: imageToLoad)
}
}
override func viewWillAppear(_ animated: Bool) {
super.viewWillAppear(animated)
navigationController?.hidesBarsOnTap = true
}
override func viewWillDisappear(_ animated: Bool) {
super.viewWillAppear(animated)
}
}
Here is where the new view is loaded:
override func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {
if let dvc = storyboard?.instantiateViewController(identifier: "Detail") as? DetailViewController {
dvc.selectedImage = imageArray[indexPath.row].image
navigationController?.pushViewController(dvc, animated: true)
}
}
The photos are picked using a navBar button item and loaded into the imageArray of type Photo here:
#objc func loadImage() {
let picker = UIImagePickerController()
picker.allowsEditing = true
picker.delegate = self
present(picker, animated: true)
}
func imagePickerController(_ picker: UIImagePickerController, didFinishPickingMediaWithInfo info: [UIImagePickerController.InfoKey : Any]) {
guard let image = info[.editedImage] as? UIImage else { return }
let imageName = UUID().uuidString
let imagePath = getDocumentsDirectory().appendingPathComponent(imageName)
// Convert to JPEG data
if let jpegData = image.jpegData(compressionQuality: 0.8) {
// We have a valid photo
try? jpegData.write(to: imagePath)
}
let photo = Photo(name: "Unkown", image: imageName)
imageArray.append(photo)
tableView.reloadData()
dismiss(animated: true)
}
func getDocumentsDirectory() -> URL {
let paths = FileManager.default.urls(for: .documentDirectory, in: .userDomainMask)
return paths[0]
}
And finally here is the Photo class that holds the photo data
import UIKit
class Photo: NSObject {
var name: String
var image: String
init(name: String, image: String) {
self.name = name
self.image = image
}
}
I can see the image name string populated in the debugger when the new view controller is loading, but for some reason it’s just a white screen displayed.
New Detail View Controller
#IBOutlet var image: UIImageView!
var url = URL(string: "")
override func viewDidLoad() {
super.viewDidLoad()
if let data = try? Data(contentsOf: url!) {
image.image = UIImage(data: data)
}
}
override func viewWillAppear(_ animated: Bool) {
super.viewWillAppear(animated)
navigationController?.hidesBarsOnTap = true
}
override func viewWillDisappear(_ animated: Bool) {
//super.viewWillAppear(animated)
}
New didSelectRowAt method
override func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {
if let dvc = storyboard?.instantiateViewController(identifier: "Detail") as? DetailViewController {
let imageName = UUID().uuidString
let urlString = getDocumentsDirectory().appendingPathComponent(imageName)
dvc.url = urlString
navigationController?.pushViewController(dvc, animated: true)
}
}

Answer 1

The problem is this line:
image.image = UIImage(named: imageToLoad)
You won’t find the image that way. That method looks in the app bundle. That’s not where the image is.
You need to fetch the image from where you put it, in the Documents directory, using essentially the reverse of the way you saved it. Get the Documents directory url, form the image file url, and load the image data from that url using the Data struct and then create the UIImage from the data.
So once you have calculated the url for this image, exactly the way you calculated it to save it in the first place, you will say
if let data = try? Data(contentsOf: url) {
image.image = UIImage(data: data)
}