从 UIImagePickerController 获取 PHAsset

Question

I am tring to get PHAsset from UIImagePickerController and using following code:

- (void)imagePickerController:(UIImagePickerController *)picker didFinishPickingMediaWithInfo:(NSDictionary<NSString *,id> *)info {
    dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{

     //   NSURL *imageURL = [info valueForKey:UIImagePickerControllerReferenceURL];
        PHAsset *phAsset = [info valueForKey:UIImagePickerControllerPHAsset];
        if (phAsset) {
            [assetsArr addObject:phAsset];
            [galleryArr addObject:[info valueForKey:UIImagePickerControllerOriginalImage]];
        }

        dispatch_async(dispatch_get_main_queue(), ^(void) {
            [self.galleryCollectionView reloadData];
            [picker dismissViewControllerAnimated:YES completion:nil];
        });
    });


}

If source type is UIImagePickerControllerSourceTypePhotoLibrary then I am able to get PHAsset by above code. But if source type is UIImagePickerControllerSourceTypeCamera then PHAsset is nil.

How can i get PHAsset in that case?

Answer 1

If UIImagePickerControllerReferenceURL have some value then you can get asset using following code:

PHFetchResult<PHAsset *> *result = [PHAsset fetchAssetsWithALAssetURLs:[NSArray arrayWithObject:imageURL] options:nil];

It may have more than one asset select according to your requirement.

Answer 2

if you get the image from taking photo, you can get the origin image by Info Dictionary

then save the image at album

and get the PHAsset object.

the code was shown as below:

  /// Save image to album.
  static func saveImageToAlbum(image: UIImage, completion: ( (Bool, PHAsset?) -> Void )? ) {
  let status = PHPhotoLibrary.authorizationStatus()
  
  if status == .denied || status == .restricted {
      completion?(false, nil)
      return
  }
  
  var placeholderAsset: PHObjectPlaceholder? = nil
  PHPhotoLibrary.shared().performChanges({
      let newAssetRequest = PHAssetChangeRequest.creationRequestForAsset(from: image)
      placeholderAsset = newAssetRequest.placeholderForCreatedAsset
  }) { (suc, error) in
      DispatchQueue.main.async {
          if suc {
              let asset = self.getAsset(from: placeholderAsset?.localIdentifier)
              completion?(suc, asset)
          } else {
              completion?(false, nil)
          }
      }
  }
}

  private static func getAsset(from localIdentifier: String?) -> PHAsset? {
  guard let id = localIdentifier else {
      return nil
  }
  let result = PHAsset.fetchAssets(withLocalIdentifiers: [id], options: nil)
  if result.count > 0{
      return result[0]
  }
  return nil

}