Question

我正在尝试制作一个TableView App，该App允许使用ImagePickerController向其中添加图像和名称，并通过AlertController TextField更改其名称

问题是ImagePicker无法拾取图像，并且调试控制台上没有显示错误。

当我单击图像进行选择时，什么也没有发生。

class ViewController: UITableViewController, UIImagePickerControllerDelegate, UINavigationControllerDelegate {

    var photos = [Photo]()

    override func viewDidLoad() {
        super.viewDidLoad()
        // Do any additional setup after loading the view.
        title = "Snapshots"
        navigationController?.navigationBar.prefersLargeTitles = true

        navigationItem.rightBarButtonItem = UIBarButtonItem(barButtonSystemItem: .add, target: self, action: #selector(addPhoto))

        let defaults = UserDefaults.standard

        if let savedPhotos = defaults.object(forKey: "photos") as? Data {
            let jsonDecoder = JSONDecoder()
            do {
                photos = try jsonDecoder.decode([Photo].self, from: savedPhotos)
            } catch {
                print("Failed to load photos.")
            }
        }

    }

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

    override func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
        guard let cell = tableView.dequeueReusableCell(withIdentifier: "Photo", for: indexPath) as? PhotoCell else {
            fatalError("Could not load the Photo Cell")
        }
        let photo = photos[indexPath.row]
        cell.textLabel?.text = photo.name
        let path = getDocumentsDirectory().appendingPathComponent(photo.image)
        cell.imageView?.image = UIImage(contentsOfFile: path.path)

        return cell
    }

    @objc func addPhoto() {
        let picker = UIImagePickerController()
        picker.isEditing = 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)

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

        let photo = Photo(name: "New Image", image: imageName)
        photos.append(photo)
        save()
        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 photo = photos[indexPath.row]

            let ac = UIAlertController(title: "What you want to do with Image?", message: nil, preferredStyle: .alert)

            ac.addTextField()

            ac.addAction(UIAlertAction(title: "Rename", style: .default) {
                [weak self, weak ac] _ in
                guard let newName = ac?.textFields?[0].text else { return }
                photo.name = newName
                self?.save()
                self?.tableView.reloadData()
            })

            ac.addAction(UIAlertAction(title: "Delete", style: .destructive) {
                [weak self] _ in
                self?.photos.remove(at: indexPath.row)
                self?.tableView.reloadData()
            })

            ac.addAction(UIAlertAction(title: "Cancel", style: .cancel, handler: nil))

            ac.addAction(UIAlertAction(title: "Open", style: .default) {
                [weak self] _ in
                if let vc = self?.storyboard?.instantiateViewController(withIdentifier: "PhotoView") as? DetailViewController {
                    vc.selectedImage = photo.name
                    self?.navigationController?.pushViewController(vc, animated: true)
                }
            })

            present(ac, animated: true)

    }

    func save() {
        let jsonEncoder = JSONEncoder()
        if let savedData = try? jsonEncoder.encode(photos) {
            let defaults = UserDefaults.standard
            defaults.set(savedData, forKey: "photos")
        } else {
            print("Failed to save photos.")
        }
    }

}

Answer 1

我实际上将您的代码压缩了很多，以便在本地进行测试，并在此处发现一个可能的问题：

guard let image = info[.editedImage] as? UIImage else { return }

如果您的用户尚未编辑照片，则返回提示，并且不再发生任何事情。

但是，如果我这样将其更改为.originalImage，则只需选择一张图像即可继续进行操作：

guard let image = info[.originalImage] as? UIImage else { return }

话虽如此，您可能要考虑使用switch语句，或者使用if / else语句来根据适合您的应用的各种类型来提供不同类型的图像。

Answer 2

您是否已在info.plist文件中添加了“照片库使用”权限？如果没有，请在info.plist中添加“隐私-照片库使用说明”。

UIImagePickerController不选择图像

2 个答案: