DAY 28『 使用相机拍照 』 ImagePicker - Part2

继昨天的实作练习，有相机，会执行以下的程序码：

1. 令 vc 为 UIImagePickerController
   let vc = UIImagePickerController()
2. 新增相机权限
   vc.sourceType = .camera // 相簿
3. 设定委任
   vc.delegate = self
4. 允许用户编辑选定的图像或影像
   vc.allowsEditing = true
5. 设定跳页
   present(vc, animated: true)

到这边会报错是正常的，因为没给它 UIImagePickerControllerDelegate
因此在专案里用 extension 去写委任

extension MainVC: UIImagePickerControllerDelegate, UINavigationControllerDelegate{
    func imagePickerController(_ picker: UIImagePickerController, didFinishPickingMediaWithInfo info: [UIImagePickerController.InfoKey : Any]) {
        // 显示 photo
        guard let image = info[UIImagePickerController.InfoKey.originalImage] as? UIImage else {return}
        imageView.image = image
        picker.dismiss(animated: true, completion: nil)
    }
    func imagePickerControllerDidCancel(_ picker: UIImagePickerController) {
        picker.dismiss(animated: true, completion: nil)
    }
}

附上完整程序码

import UIKit

class MainVC: UIViewController {

    @IBOutlet weak var imageView: UIImageView!
    @IBOutlet weak var takePhoto: UIButton!
    
    override func viewDidLoad() {
        super.viewDidLoad()
        self.navigationController?.setNavigationBarHidden(true, animated: false) // 隐藏指示条
    }
    
    @IBAction func didTapButton(btn: UIButton) {
        let vc = UIImagePickerController()
        if !UIImagePickerController.isSourceTypeAvailable(.camera) {
            let alertController = UIAlertController(title: "ERROR", message: "Device has no camera.", preferredStyle: .alert)
            let okAction = UIAlertAction(title: "Alright", style: .default, handler: { (alert: UIAlertAction!) in
            })
            alertController.addAction(okAction)
            self.present(alertController, animated: true, completion: nil)
            print("ERROR：没有相机功能！")
        }
        else { vc.sourceType = .camera }
        vc.delegate = self
        present(vc, animated: true)
    }
}

extension MainVC: UIImagePickerControllerDelegate, UINavigationControllerDelegate{
    func imagePickerController(_ picker: UIImagePickerController, didFinishPickingMediaWithInfo info: [UIImagePickerController.InfoKey : Any]) {
        picker.dismiss(animated: true, completion: nil)
        // 显示 photo
        guard let image = info[UIImagePickerController.InfoKey.originalImage] as? UIImage else {return}
        imageView.image = image
    }
    func imagePickerControllerDidCancel(_ picker: UIImagePickerController) {
        picker.dismiss(animated: true, completion: nil)
    }
}

为了测试和使用相机，您必须使用真正的连接设备，若烧在模拟器，会报错：Source type 1 not available

这样就完成从相簿选取照片的实作了！明天会分享从相簿选取照片（ 有裁剪照片功能 ），敬请期待！