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SOLVED: Problems with Milestone 10-12

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Hi, everyone.

Currently, I am on Milestone projects 10-12 and stuck.

So, where I am:

  • I have already built a basic interface: I used UITableViewController, changed everything in the interface builder, and used numberOfRowsInSection and cellForRowAt.
  • I created a new custom class called Picture with the name and image property;
  • then I created an imagePickerController with UUID, jpegData.write and etc;
  • then I created DetailViewController and tied it up with the imageView of DetailedViewController at the Storyboard; my DetailViewController file has the property selectedImage which conforms custom Picture class;
  • Finally, I have overridden didSelectRowAt method and made the connection between view controller and detailed view controller. (I left the task of renaming and the task of being able to use a photo from the camera for the end.)

So, when I run the app everything works fine: I can open the picker and add photos saved on my phone. When I click on the photo, the Detailviewcontroller appears, BUT... but the photo is not displayed for some reason.

I have already been stuck for two days))) and somehow I know where the problem is:

import UIKit

class DetailViewController: UIViewController {
    @IBOutlet var imageView: UIImageView!
    var selectedImage: Picture?

    override func viewDidLoad() {
        super.viewDidLoad()

        title = selectedImage?.name

        if let imageToLoad = selectedImage {
            imageView.image = UIImage(contentsOfFile: imageToLoad.image)

            ///I HAVE TRIED PRINT(imageView.image!) AND I HAVE GOT TERRIBLE CRUSH.
        }
    }
}

Now I know that for some reason my imageView.image is left "empty". But everything that I have tried is not working.

So, the question why dosn't my imageView.image work? and why while I run the app my detail view controler is not showing the image?

I would be extremely grateful if someone would help me to solve the problem.

3      

Hi @Mykola!

I suspect you forgot to retrieve the path. You saved the image before displaying it in DetailView so it should be something like this.

class DetailViewController: UIViewController {

  @IBOutlet weak var imageView: UIImageView!
  var selectedImage: String?

  override func viewDidLoad() {
    super.viewDidLoad()

    if let image = selectedImage {
      let path = getDocumentsDirectory().appendingPathComponent(image)
      imageView.image = UIImage(contentsOfFile: path.path)
    }
  }

  func getDocumentsDirectory() -> URL {
    let paths = FileManager.default.urls(for: .documentDirectory, in: .userDomainMask)
    return paths[0]
  }

}

for Picture Class you can use this:

class Picture: NSObject, Codable {
  var name: String
  var image: String

  init(name: String, image: String) {
    self.name = name
    self.image = image
  }
}

4      

@ygeras

Thanks a lot! I have tried but it still does not work. So I will share all my code with you)

class ViewController: UITableViewController, UIImagePickerControllerDelegate, UINavigationControllerDelegate {
    var pictures = [Picture]()

    override func viewDidLoad() {
        super.viewDidLoad()

        navigationItem.leftBarButtonItem = UIBarButtonItem(barButtonSystemItem: .add, target: self, action: #selector(selectPicture))
    }

    override func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
        return pictures.count
    }

    override func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
        let cell = tableView.dequeueReusableCell(withIdentifier: "Picture", for: indexPath)
        let picture = pictures[indexPath.row]

        cell.textLabel?.text = picture.name

        return cell
    }

    @objc func selectPicture() {
        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().appendingPathExtension(imageName)

        if let jpegData = image.jpegData(compressionQuality: 0.8) {
            try? jpegData.write(to: imagePath)
        }

        let name = "Unknown"

        let picture = Picture(name: name, image: imageName)
        pictures.append(picture)
        tableView.reloadData()

        dismiss(animated: true)
    }

    func getDocumentsDirectory() -> URL {
        let paths = FileManager.default.urls(for: .documentDirectory, in: .userDomainMask)
        return paths[0]
    }

    override func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {
        let dvc = storyboard?.instantiateViewController(withIdentifier: "Detail") as! DetailViewController
        let picture = pictures[indexPath.row]
        dvc.selectedImage = picture
        navigationController?.pushViewController(dvc, animated: true)
    }
}

Now DetailView with your suggestions:

class DetailViewController: UIViewController {
    @IBOutlet var imageView: UIImageView!
    var selectedImage: Picture?

    override func viewDidLoad() {
        super.viewDidLoad()

        title = selectedImage?.name
        navigationItem.largeTitleDisplayMode = .never

        if let imageToLoad = selectedImage?.image {
            let path = getDocumentsDirectory().appendingPathComponent(imageToLoad)
                  imageView.image = UIImage(contentsOfFile: path.path)
        }
    }

    func getDocumentsDirectory() -> URL {
        let paths = FileManager.default.urls(for: .documentDirectory, in: .userDomainMask)
        return paths[0]
      }
}

and here is my Picture class:

class Picture: NSObject, Codable {
    var name: String
    var image: String

    init(name: String, image: String) {
        self.name = name
        self.image = image
    }
}

I would be very appreciated if you check the code!

3      

Your mistake most probably here in DetailView

var selectedImage: Picture?

you have to pass it as

var selectedImage: String?

also in didSelectRowAt pass a string not an object Picture

override func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {
        let dvc = storyboard?.instantiateViewController(withIdentifier: "Detail") as! DetailViewController
        dvc.selectedImage = pictures[indexPath.row].image // add 'image'
        navigationController?.pushViewController(dvc, animated: true)
    }

if it doens't help let me know. Will check line by line tomorrow :)

4      

@ygeras

It still does not work) Please, check it by the line tomorrow. 🙏

Have goot night!)

3      

Now cannot fall asleep )))) unless try to solve it. So let's start with ViewController Class

class ViewController: UITableViewController, UIImagePickerControllerDelegate, UINavigationControllerDelegate {
    var pictures = [Picture]()

    override func viewDidLoad() {
        super.viewDidLoad()

        navigationItem.leftBarButtonItem = UIBarButtonItem(barButtonSystemItem: .add, target: self, action: #selector(selectPicture))

        // This is to load info on images we saved before
        load()
    }

    override func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
        return pictures.count
    }

    override func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
        let cell = tableView.dequeueReusableCell(withIdentifier: "Picture", for: indexPath)
        let picture = pictures[indexPath.row]
        cell.textLabel?.text = picture.name

        return cell
    }

    @objc func selectPicture() {
        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) // NOT appendingPathExtension(imageName)

        if let jpegData = image.jpegData(compressionQuality: 0.8) {
            try? jpegData.write(to: imagePath)
        }

        // let name = "Unknown" // Why do declare it here and then pass below. So we can remove it

        let picture = Picture(name: "Unknown", image: imageName) // You use it once so place string "Unknown" directly
        pictures.append(picture)
        tableView.reloadData()

        // So we picked up image gave it a name, gave it a path where we wrote image to and added to pictures array
        // Let's save it to UserDefaults so next time view appears all info is retrieved from there

        save()

        dismiss(animated: true)
    }

    func getDocumentsDirectory() -> URL {
        let paths = FileManager.default.urls(for: .documentDirectory, in: .userDomainMask)
        return paths[0]
    }

    override func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {
      // It is advisable to use if let to instantiate VCs, if something goes wrong but let's disregard it for now
        let dvc = storyboard?.instantiateViewController(withIdentifier: "Detail") as! DetailViewController
        dvc.selectedImage = pictures[indexPath.row] // OK let's pass the whole object :)
        navigationController?.pushViewController(dvc, animated: true)
    }

      func save() {
    let jsonEncoder = JSONEncoder()

    if let picturesSaved = try? jsonEncoder.encode(pictures) {
      let defaults = UserDefaults.standard
      defaults.set(picturesSaved, forKey: "pictures")
    } else {
      print("Failed to save pictures data.")
    }
  }

  // This is to retrieve all images we saved before

   func load() {
    let defaults = UserDefaults.standard

    if let picturesSaved = defaults.object(forKey: "pictures") as? Data {
      let jsonDecoder = JSONDecoder()

      do {
        pictures = try jsonDecoder.decode([Picture].self, from: picturesSaved)
      } catch {
        print("Failed to load pictures data.")
      }
    }
  }

}

In DetailView basically we leave the same.

class DetailViewController: UIViewController {
    @IBOutlet var imageView: UIImageView!
    var selectedImage: Picture?

    override func viewDidLoad() {
        super.viewDidLoad()

        title = selectedImage?.name
        navigationItem.largeTitleDisplayMode = .never

        if let imageToLoad = selectedImage?.image {
            let path = getDocumentsDirectory().appendingPathComponent(imageToLoad)
                  imageView.image = UIImage(contentsOfFile: path.path)
        }
    }

    func getDocumentsDirectory() -> URL {
        let paths = FileManager.default.urls(for: .documentDirectory, in: .userDomainMask)
        return paths[0]
      }
}

So the issues should have been also here appendingPathExtension(imageName). You added it as a file extension to save not as PathComponent.

PS Before running on simulator, delete app so that all leftovers from previous app are gone.

4      

Thanks Yuri. Now its working! Going to learn where I made mistakes! Best wishes!

3      

Glad to hear it helped! Please mark post as solved :) Cheers and keep coding!

4      

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