覆盖现有的AVAsset

Question

我可以从相机胶卷中选择图像，然后将其保存到自定义相册中。 由于重复保存，这会增加计数

我该怎么做才能删除资产或其他任何方式？

  __block  UIImage *imTransfer=nil;
            PHImageRequestOptions * imageRequestOp = [[PHImageRequestOptions alloc] init];
            imageRequestOp.synchronous = YES;



            [[PHImageManager defaultManager] requestImageDataForAsset:photoAssety options:imageRequestOp resultHandler:^(NSData *imageData, NSString *dataUTI, UIImageOrientation orientation, NSDictionary *info) {

                 imTransfer=[UIImage imageWithData:imageData];
                   NSLog(@"info = %@", imTransfer);
            }];


            __block PHFetchResult *photosAsset;
            __block PHAssetCollection *collection;
            __block PHObjectPlaceholder *placeholder;

            // Find the album
            PHFetchOptions *fetchOptions = [[PHFetchOptions alloc] init];
            fetchOptions.predicate = [NSPredicate predicateWithFormat:@"title = %@", BottomAlbumName_string];
            collection = [PHAssetCollection fetchAssetCollectionsWithType:PHAssetCollectionTypeAlbum
                                                                  subtype:PHAssetCollectionSubtypeAny
                                                                  options:fetchOptions].firstObject;
            // Create the album
            if (!collection)
            {
                [[PHPhotoLibrary sharedPhotoLibrary] performChanges:^{
                    PHAssetCollectionChangeRequest *createAlbum = [PHAssetCollectionChangeRequest creationRequestForAssetCollectionWithTitle:BottomAlbumName_string];
                    placeholder = [createAlbum placeholderForCreatedAssetCollection];
                } completionHandler:^(BOOL success, NSError *error) {
                    if (success)
                    {
                        PHFetchResult *collectionFetchResult = [PHAssetCollection fetchAssetCollectionsWithLocalIdentifiers:@[placeholder.localIdentifier]
                                                                                                                    options:nil];
                        collection = collectionFetchResult.firstObject;
                    }
                }];
            }

            // Save to the album
            [[PHPhotoLibrary sharedPhotoLibrary] performChanges:^{
                PHAssetChangeRequest *assetRequest = [PHAssetChangeRequest changeRequestForAsset:photoAssety];
                placeholder = [assetRequest placeholderForCreatedAsset];
                photosAsset = [PHAsset fetchAssetsInAssetCollection:collection options:nil];
                PHAssetCollectionChangeRequest *albumChangeRequest = [PHAssetCollectionChangeRequest changeRequestForAssetCollection:collection
                                                                                                                              assets:photosAsset];

               // [albumChangeRequest removeAssets:@[placeholder].firstObject];
                [albumChangeRequest addAssets:@[placeholder]];

                  [self toggleFavoriteForAsset:photoAssety];





            } completionHandler:^(BOOL success, NSError *error) {
                if (success)
                {


//                        NSString *UUID = [placeholder.localIdentifier substringToIndex:36];
//                        self.photo.assetURL = [NSString stringWithFormat:@"assets-library://asset/asset.PNG?id=%@&ext=JPG", UUID];
//                        [self savePhoto];
                    }
                    else
                    {
                        NSLog(@"%@", error);
                    }
                }];