我想要在我的应用程序中访问用户照片库中的照片,我正在查看UIImagePickerController来执行此操作。然而,我想知道是否有可能访问和查看照片库中的照片,而不是真正将这些照片存储在应用程序中?因此,基本上应用程序会存储对所选照片的引用,而不是存储照片本身。这是为了防止应用程序占用大量空间来存储每张照片。
谢谢!
发布于 2017-05-13 02:56:47
这不是那么简单,但正如Rob提到的,你可以保存照片资源的url,然后使用Photos框架获取它。您可以使用PHImageManager方法requestImageData获取它们。
import UIKit
import Photos
class ViewController: UIViewController, UINavigationControllerDelegate, UIImagePickerControllerDelegate {
@IBOutlet weak var imageView: UIImageView!
let galleryPicker = UIImagePickerController()
// create a method to fetch your photo asset and return an UIImage on completion
override func viewDidLoad() {
super.viewDidLoad()
// lets add a selector to when the user taps the image
imageView.isUserInteractionEnabled = true
imageView.addGestureRecognizer(UITapGestureRecognizer(target: self, action: #selector(openPicker)))
// request authorization
switch PHPhotoLibrary.authorizationStatus() {
case .authorized:
print("The user has explicitly granted your app access to the photo library.")
return
case .denied:
print("The user has explicitly denied your app access to the photo library.")
case .notDetermined:
PHPhotoLibrary.requestAuthorization { status in
print("status", status)
}
case .restricted:
print("Your app is not authorized to access the photo library, and the user cannot grant such permission.")
default: break
}
}
// opens the image picker for photo library
@objc func openPicker(_ gesture: UITapGestureRecognizer) {
galleryPicker.sourceType = .photoLibrary
galleryPicker.delegate = self
present(galleryPicker, animated: true)
}
override func viewDidAppear(_ animated: Bool) {
super.viewDidAppear(animated)
self.imageView.contentMode = .scaleAspectFit
// check if there is an url saved in the user defaults
// and fetch its first object (PHAsset)
if let assetURL = UserDefaults.standard.url(forKey: "assetURL") {
if let asset = PHAsset.fetchAssets(withALAssetURLs: [assetURL], options: nil).firstObject {
asset.asyncImageData { data, _, _, _ in
print("fetched")
guard let data = data else { return }
self.imageView.image = UIImage(data: data)
}
} else {
print("assetURL:", assetURL)
self.imageView.image = UIImage(contentsOfFile: assetURL.path)
}
} else {
print("no assetURL found")
}
}
func imagePickerControllerDidCancel(_ picker: UIImagePickerController) {
dismiss(animated: true)
print("canceled")
}
func imagePickerController(_ picker: UIImagePickerController, didFinishPickingMediaWithInfo info: [UIImagePickerController.InfoKey : Any]) {
self.imageView.image = info[.originalImage] as? UIImage
if let phAsset = info[.phAsset] as? PHAsset {
phAsset.asyncURL { url in
guard let url = url else { return }
UserDefaults.standard.set(url, forKey: "assetURL")
print("assetURL saved")
}
}
dismiss(animated: true)
}
}
extension PHAsset {
func asyncURL(_ completion: @escaping ((URL?) -> Void)) {
switch mediaType {
case .image:
let options: PHContentEditingInputRequestOptions = .init()
options.canHandleAdjustmentData = { _ in true }
requestContentEditingInput(with: options) { editingInput, _ in
completion(editingInput?.fullSizeImageURL)
}
case .video:
let options: PHVideoRequestOptions = .init()
options.version = .original
PHImageManager.default()
.requestAVAsset(forVideo: self, options: options) { asset, _, _ in
completion((asset as? AVURLAsset)?.url)
}
default:
completion(nil)
}
}
func asyncImageData(version: PHImageRequestOptionsVersion = .original, completion: @escaping (Data?, String?, UIImage.Orientation, [AnyHashable : Any]?) -> ()) {
let options = PHImageRequestOptions()
options.version = version
PHImageManager.default()
.requestImageData(for: self, options: options, resultHandler: completion)
}
}
extension URL {
var phAsset: PHAsset? {
PHAsset.fetchAssets(withALAssetURLs: [self], options: nil).firstObject
}
}
注意:不要忘记编辑您的信息列表,并添加“隐私-图片库使用说明”
https://stackoverflow.com/questions/43943629
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