允许用户从相机、照片库或相册中选择图像并遇到我无法解决的错误

Posted 2023-05-07

【中文标题】允许用户从相机、照片库或相册中选择图像并遇到我无法解决的错误

【英文标题】：Allowing user to select image from Camera, Photo Library or Photo Albums and hit an error I cannot solve

【发布时间】：2020-04-29 14:11:04

【问题描述】：

我一直在关注 David Thorn 的视频，以允许用户使用他们的相机拍摄图像或从他们的照片库或相册中导入图像。

https://www.youtube.com/watch?v=wDzk5KDe6Uw

我一个字一个字地按照指南进行操作，但遇到了下图中的错误。我已将我的代码与本教程的 Github 中的代码进行了比较，但找不到解决方法。

Here is a screen shot of the errors(not enough reputation to embed in post)

错误是

1！ “ViewController”类型的值没有成员“selectedImage”

2！ nil 不能分配给类型 '(UIImagePickerController, [UIImagePickerController.InfoKey : Any]) -> ()'

2！ 'nil' 不能分配给类型 '(UIImagePickerController, [UIImagePickerController.InfoKey : Any]) -> ()'

.swift 文件的类型为 UIViewController。

这是我输入的代码；

public var imagePickerController: UIImagePickerController?

public var defaultImageUrl: URL?

   internal var selectedImage: UIImage? 
       get 
           return self.selectedImageView.image
       

       set 
           switch newValue 
           case nil:
               self.selectedImageView.image = nil
               self.selectImageButton.isEnabled = true
               self.selectImageButton.alpha = 1

               self.removeImageButton.isEnabled = false
               self.removeImageButton.alpha = 0.5
           default:
               self.selectedImageView.image = newValue
               self.selectImageButton.isEnabled = false
               self.selectImageButton.alpha = 0.5

               self.removeImageButton.isEnabled = true
               self.removeImageButton.alpha = 1
           
       
   
//This outlet, 'selectedImageContainer' was guessed from observing the tutorial stacked their UIImageView in a UIView.

@IBOutlet weak var selectedImageContainer: UIView!
@IBOutlet weak var selectedImageView: UIImageView!


@IBOutlet weak var selectImageButton: UIButton! 
    didSet 
        guard let button = self.selectImageButton else  return 
        button.isEnabled = true
        button.alpha = 1
    


@IBOutlet weak var removeImageButton: UIButton! 
    didSet 
        guard let button = self.removeImageButton else  return 
        button.isEnabled = false
        button.alpha = 0.5
    

override func viewDidLoad() 
super.viewDidLoad()
self.selectedImageView.contentMode = .scaleAspectFit
self.selectImageButton.isEnabled = self.selectedImage == nil
self.selectImageButton.alpha = 1




@IBAction func selectImageButtonAction(_ sender: Any) 


    if self.imagePickerController != nil 
        self.imagePickerController?.delegate = nil
        self.imagePickerController = nil
    
    self.imagePickerController = UIImagePickerController.init()

    let alert = UIAlertController.init(title: "Select Source Type", message: nil, preferredStyle: .actionSheet)

    if UIImagePickerController.isSourceTypeAvailable(.camera) 
        alert.addAction(UIAlertAction.init(title: "Camera", style: .default, handler:  (_) in
            self.presentImagePicker(controller: self.imagePickerController!, source: .camera)
        ))
    

    if UIImagePickerController.isSourceTypeAvailable(.photoLibrary) 
        alert.addAction(UIAlertAction.init(title: "Photo Library", style: .default, handler:  (_) in
            self.presentImagePicker(controller: self.imagePickerController!, source: .photoLibrary)
        ))
    

    if UIImagePickerController.isSourceTypeAvailable(.savedPhotosAlbum) 
        alert.addAction(UIAlertAction.init(title: "Saved Albums", style: .default, handler:  (_) in
            self.presentImagePicker(controller: self.imagePickerController!, source: .savedPhotosAlbum)
        ))
    

    alert.addAction(UIAlertAction.init(title: "Cancel", style: .cancel))

    self.present(alert, animated: true)


internal func presentImagePicker(controller: UIImagePickerController , source: UIImagePickerController.SourceType) 
    controller.delegate = self
    controller.sourceType = source
    self.present (controller, animated: true)


@IBAction func removeImageButtonAction(_ sender: UIButton) 
    self.selectedImage = nil





extension ViewController: UIImagePickerControllerDelegate, UINavigationControllerDelegate 


func imagePickerController(_ picker: UIImagePickerController, didFinishPickingMediaWithInfo info: [UIImagePickerController.InfoKey : Any]) 

    guard let image = info[UIImagePickerController.InfoKey.originalImage] as? UIImage else 
        return self.imagePickerControllerDidCancel(picker)
    

    self.selectedImage = image

    picker.dismiss(animated: true) 
        picker.delegate = nil
        self.imagePickerController = nil
    


func imagePickerControllerDidCancel(_ picker: UIImagePickerController) 
     picker.dismiss(animated: true) 
        picker.delegate = nil
        self.imagePickerController = nil
    

【参考方案1】：

我已经回答了我自己的问题！

扩展类 ViewController 命名不正确。我的 .swift 文件被命名为其他名称。

我还从代码顶部的原始类中移动了 UIImageViewControllerDelegate 和 UINavigatonControllerDeletage，因此它只出现在扩展中！