How to retrieve PHAsset from PHPicker? - ios

Question

In WWDC20 apple introduced PHPicker - the modern replacement for UIImagePickerController.
I'm wondering if it's possible to retrieve PHAsset using the new photo picker?
Here is my code:
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

I managed to find an answer from the developers of this framework on the apple forum:
Yes, PHPickerResult has the assetIdentifier property which can contain
a local identifier to fetch the PHAsset from the library. To have
PHPicker return asset identifiers, you need to initialize
PHPickerConfiguration with the library.
Please note that PHPicker does not extend the Limited Photos Library
access for the selected items if the user put your app in Limited
Photos Library mode. It would be a good opportunity to reconsider if
the app really needs direct Photos Library access or can work with
just the image and video data. But that really depend on the app.
The relevant section of the "Meet the new Photos picker" session
begins at 10m 20s.
Sample code for PhotoKit access looks like this:
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
}
}