如何使用 Swift 通过 PHAsset 访问 UIImage 的元数据
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【中文标题】如何使用 Swift 通过 PHAsset 访问 UIImage 的元数据【英文标题】:How to get access to metadata for UIImage via PHAsset using Swift 【发布时间】:2019-10-17 20:11:32 【问题描述】:我正在尝试获取此工作代码,该代码通过从 ImagePicker 中的 selectedImage 检索 UIImage 并通过 savePhoto 方法保存它,以获取 UImage 的元数据:
原始代码:
func imagePickerController(_ picker: UIImagePickerController, didFinishPickingMediaWithInfo info: [UIImagePickerController.InfoKey : Any])
if let selectedImage = info[UIImagePickerController.InfoKey.originalImage] as? UIImage
//Successfully got the image, now upload it
//Get a reference to the camera view controller and call the savePhoto method
let cameraVC = self.selectedViewController as? CameraViewController
if let cameraVC = cameraVC
cameraVC.savePhoto(image: selectedImage)
//Dismiss the picker
picker.dismiss(animated: true, completion: nil)
这是我尝试过的,但是 thisAsset 总是返回 nil 所以它基本上跳过了整个方法。
我试过的代码:
func imagePickerController(_ picker: UIImagePickerController, didFinishPickingMediaWithInfo info: [UIImagePickerController.InfoKey : Any])
var arrImageIdentifiers = String()
if let thisAsset:PHAsset = info[UIImagePickerController.InfoKey.phAsset] as? PHAsset
arrImageIdentifiers.append(thisAsset.localIdentifier)
//Get a reference to the camera view controller and call the savePhoto method
let cameraVC = self.selectedViewController as? CameraViewController
let manager = PHImageManager.default()
manager.requestImage(for: thisAsset, targetSize: CGSize(width: 300.0, height: 300.0), contentMode: .aspectFit, options: nil, resultHandler: (thisImage, _) in
if let cameraVC = cameraVC
cameraVC.savePhoto(image: thisImage!)
)
self.dismiss(animated: true, completion: nil)
从上面的原始代码中获取照片元数据(创建日期、位置等)的最简单方法是什么?
【问题讨论】:
【参考方案1】:您从第一个代码中获得的图像不包含元数据。您的第二个代码更接近正确;您需要返回 PHAsset 并从照片库中获取元数据。
这是我尝试过的,但
thisAsset
总是返回 nil
因为您忘记获得照片库的用户授权。否则,您将无法访问 PHAsset。
【讨论】:
【参考方案2】:extension PHAsset
func metadata(_ completion: @escaping (Metadata?) -> Void)
let options = PHContentEditingInputRequestOptions()
options.isNetworkAccessAllowed = true
requestContentEditingInput(with: options) input, _ in
guard let url = input?.fullSizeImageURL,
let image = CIImage(contentsOf: url) else
completion(nil)
return
let properties = image.properties
let tiffDict = properties["TIFF"] as? [String: Any]
let make = tiffDict?["Make"] as? String ?? ""
completion(make)
asset.metadata metadata in
guard let metadata = metadata else
return
// You can explore all available metadata values here.
【讨论】:
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