如何从PHAsset中检索PHPicker？

Question

在WWDC20中，苹果推出了PHPicker -- UIImagePickerController的现代替代品。

我想知道是否可以使用新的照片选择器检索PHAsset？

这里是我的代码

private func presentPicker(filter: PHPickerFilter) {
    var configuration = PHPickerConfiguration()
    configuration.filter = filter
    configuration.selectionLimit = 0
    
    let picker = PHPickerViewController(configuration: configuration)
    picker.delegate = self
    present(picker, animated: true)
}


func picker(_ picker: PHPickerViewController, didFinishPicking results: [PHPickerResult]) {
    dismiss(animated: true)
}

Answer 1

我在苹果论坛上设法从这个框架的开发人员那里找到了答案。

是的，PHPickerResult具有assetIdentifier属性，该属性可以包含一个本地标识符，以便从库中获取PHAsset。要让PHPicker返回资产标识符，需要使用库初始化PHPickerConfiguration。 请注意，如果用户将应用程序置于有限照片库模式中，则PHPicker不会为所选项目扩展有限照片库访问权限。这将是一个很好的机会重新考虑，如果应用程序真的需要直接的照片库访问，或可以只处理图像和视频数据。但这真的取决于应用程序。 “满足新照片选择器”会话的相关部分从10米20开始。

用于访问的PhotoKit示例代码如下所示：

import UIKit
import PhotosUI
class PhotoKitPickerViewController: UIViewController, PHPickerViewControllerDelegate {
    @IBAction func presentPicker(_ sender: Any) {
            let photoLibrary = PHPhotoLibrary.shared()
            let configuration = PHPickerConfiguration(photoLibrary: photoLibrary)
            let picker = PHPickerViewController(configuration: configuration)
            picker.delegate = self
            present(picker, animated: true)
    }
    
    func picker(_ picker: PHPickerViewController, didFinishPicking results: [PHPickerResult]) {
            picker.dismiss(animated: true)
            
            let identifiers = results.compactMap(\.assetIdentifier)
            let fetchResult = PHAsset.fetchAssets(withLocalIdentifiers: identifiers, options: nil)
            
            // TODO: Do something with the fetch result if you have Photos Library access
    }
}