如何使用 Swift 通过 PHAsset 访问 UIImage 的元数据

Question

我正在尝试获取此工作代码，该代码通过 ImagePicker 中的 selectedImage 检索 UIImage 并通过 savePhoto 方法保存它，同时获取 UImage 的元数据：

原码：

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？

Answer 1

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. 
}

Answer 2

您从第一个代码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。

This is what I tried but thisAsset always comes back nil

因为您忘记为照片库获取用户授权。否则，您将无法访问 PHAsset。

如何使用 Swift 通过 PHAsset 访问 UIImage 的元数据

How to get access to metadata for UIImage via PHAsset using Swift

ios

swift

phasset