ios - 画像ピッカーを使用した後、ImageView に画像が表示されない

Question

写真ライブラリの写真で ImageView を更新する簡単なアプリを作成しようとしています。写真ライブラリを開いて写真を選択できますが、その後、ImageViewer のデフォルトの画像が表示されません。理由はありますか？

import UIKit

class ViewController: UIViewController, UITextFieldDelegate, UIImagePickerControllerDelegate, UINavigationControllerDelegate {


    override func viewDidLoad() {
        super.viewDidLoad()
        // Do any additional setup after loading the view.
    }

    @IBOutlet weak var photoView: UIImageView!
    @IBAction func testGesture(_ sender: UITapGestureRecognizer) {

       let imagePickerController = UIImagePickerController()
        imagePickerController.sourceType = .photoLibrary
        imagePickerController.delegate = self
        present(imagePickerController, animated: true, completion: nil)
    }

    func imagePickerControllerDidCancel(_ picker: UIImagePickerController) {
        dismiss(animated: true, completion: nil)

    }

    private func imagePickerController(_ picker: UIImagePickerController, didFinishPickingMediaWithInfo info: [String : Any]) {

        guard let selectedImage = info[UIImagePickerController.InfoKey.originalImage.rawValue] as? UIImage else {
            fatalError("Expected a dictionary containing an image, but was provided the following: \(info)")
        }

        photoView.image = selectedImage
        dismiss(animated: true, completion: nil)
    }

}