在 @IBAction 裡

1. 令 vc 為 UIImagePickerController
   let vc = UIImagePickerController()
2. 新增相簿權限
   vc.sourceType = .photoLibrary // 相簿
3. 設定委任
   vc.delegate = self
4. 允許用戶編輯選定的圖像或影像
   vc.allowsEditing = true
5. 設定跳頁
   present(vc, animated: true)

到這邊會報錯是正常的，因為沒給它 UIImagePickerControllerDelegate
因此在專案裡用 extension 去寫委任

extension MainVC: UIImagePickerControllerDelegate, UINavigationControllerDelegate{
    func imagePickerController(_ picker: UIImagePickerController, didFinishPickingMediaWithInfo info: [UIImagePickerController.InfoKey : Any]) {
        if let image = info[UIImagePickerController.InfoKey(rawValue: "UIImagePickerControllerEditedImage") ] as? UIImage{
            imageView.image = image
        }
        picker.dismiss(animated: true, completion: nil)
    }
    func imagePickerControllerDidCancel(_ picker: UIImagePickerController) {
        picker.dismiss(animated: true, completion: nil)
    }
}

附上完整程式碼

import UIKit

class MainVC: UIViewController {

    @IBOutlet weak var imageView: UIImageView!
    
    override func viewDidLoad() {
        super.viewDidLoad()
        self.navigationController?.setNavigationBarHidden(true, animated: false)
    }
    @IBAction func didTapButton(_:UIButton) {
        let vc = UIImagePickerController()
        vc.sourceType = .photoLibrary
        vc.delegate = self
        vc.allowsEditing = true
        present(vc, animated: true)
    }
}

extension MainVC: UIImagePickerControllerDelegate, UINavigationControllerDelegate{
    func imagePickerController(_ picker: UIImagePickerController, didFinishPickingMediaWithInfo info: [UIImagePickerController.InfoKey : Any]) {
        if let image = info[UIImagePickerController.InfoKey(rawValue: "UIImagePickerControllerEditedImage") ] as? UIImage{
            imageView.image = image
        }
        picker.dismiss(animated: true, completion: nil)
    }
    func imagePickerControllerDidCancel(_ picker: UIImagePickerController) {
        picker.dismiss(animated: true, completion: nil)
    }
}

這樣就完成從相簿選取照片的實作了！

#完賽心得

13th鐵人賽到今天完賽了，終於完成連續30天的自我挑戰！透過鐵人賽，讓自己從最基本的說明介紹開始，更扎實地打好基本功，也更了解那些官方文件未提及的面向。這30天記錄了使用 swift 開發實作的過程，希望自己在完賽後，也能持續使用 swift 開發更多實作。感謝各位邦友收看!