Choosing Photo with UIImagePickerController

First of all, in the file ViewController.swift, image view, label and button clicked function are defined.

@IBOutlet weak var imageView: UIImageView!
@IBOutlet weak var resultLabel: UILabel!

override func viewDidLoad() {
        super.viewDidLoad()
        // ...
}

@IBAction func selectBtnTapped(_ sender: Any) {
        // ...
}

Before implementing the selectBtnTapped method, you need to declare UIImagePickerControllerDelegate and UINavigationControllerDelegate next to UIViewController to use Picker View.

class ViewController: UIViewController, UIImagePickerControllerDelegate, UINavigationControllerDelegate {
...

It's ready to implement picker view now.

@IBAction func selectBtnTapped(_ sender: Any) {
        let picker = UIImagePickerController()
        picker.delegate = self
        picker.allowsEditing = true
        picker.sourceType = .photoLibrary
        self.present(picker, animated: true, completion: nil)
}

And thaen, implement the didFinishPickingMediaWithInfo function to complete the photo selection.

func imagePickerController(_ picker: UIImagePickerController, didFinishPickingMediaWithInfo info: [String : Any]) {
        imageView.image = info[UIImagePickerControllerEditedImage] as? UIImage
        self.dismiss(animated: true, completion: nil)
}

Finally, in the Info.plist file we create a row named "Privacy - Photo Library Usage Description". In section "Value" you can write the message you want.