swift5如何在用户授予有限访问权限以选择某些照片后仅显示有限的照片库

Posted 2023-03-10

【中文标题】swift5如何在用户授予有限访问权限以选择某些照片后仅显示有限的照片库

【英文标题】：swift5 how to only display limited photo library after user has granted limited access to select some photos

【发布时间】：2020-11-07 05:56:08

【问题描述】：

在 WWDC2020 中，引入了新的 phpickerViewController 和新的 PHPhotoLibrary.authorizationStatus(limited)。但我遇到了以下问题：

当用户点击一个按钮以显示苹果的多个图像选择器并将 requestAuthorization 显示为代码时：

 let requiredAccessLevel: PHAccessLevel = .readWrite
 PHPhotoLibrary.requestAuthorization(for: requiredAccessLevel)  (authorizationStatus) in
       switch authorizationStatus 
       case .authorized:
           DispatchQueue.main.async 
               self.presentImagePicker()
            
       case .limited:
           DispatchQueue.main.async 
               self.presentImagePicker()
            
       default:
           break
       

self.presentImagePicker() 函数：

 func presentImagePicker() 
 var configuration = PHPickerConfiguration(photoLibrary: .shared())
 configuration.filter = .images
 configuration.selectionLimit = self.imageCountMax - self.images.count
 let picker = PHPickerViewController(configuration: configuration)
 picker.delegate = self

 let accessLevel: PHAccessLevel = .readWrite
 let authorizationStatus = PHPhotoLibrary.authorizationStatus(for: accessLevel)

 switch authorizationStatus 
 case .authorized:
     DispatchQueue.main.async 

         self.present(picker, animated: true)
     
 case .limited:
     DispatchQueue.main.async 
         // Here I don't know how to display only limited photo library to users (after user has selected some photos through the limited access)
     
 default:
     break
 

我的问题：请看代码2，case .limited: DispatchQueue.main.async ，我想我应该把有限的照片库放在这个块中，但我不知道如何只显示有限的照片库用户。

【参考方案1】：

您可以将这个PHPhotoLibrary.shared().presentLimitedLibraryPicker(from: self) 方法用于.limited

DispatchQueue.main.async 
         // Here I don't know how to display only limited photo library to users (after user has selected some photos through the limited access)
        PHPhotoLibrary.shared().register(self)
        PHPhotoLibrary.shared().presentLimitedLibraryPicker(from: self)
     

然后你必须使用委托方法来获取更新的图像。

func photoLibraryDidChange(_ changeInstance: PHChange) 
        let fetchOptions = PHFetchOptions()
        self.allPhotos = PHAsset.fetchAssets(with: .image, options: fetchOptions)
    

【讨论】：

我遇到了同样的问题。您能否解释一下您是如何声明 allPhotos 的？

@Quailcreek : var allPhotos: PHFetchResult!