FBSDKShareVideo不首先保存到用户的相机胶卷

Question

尝试分享在Facebook上下载到应用中的视频。但我能找到的唯一方法是：

ALAssetsLibrary *library = [[ALAssetsLibrary alloc] init];
            ALAssetsLibraryWriteVideoCompletionBlock videoWriteCompletionBlock =
            ^(NSURL *newURL, NSError *error) {
                if (error) {
                    NSLog( @"Error writing image with metadata to Photo Library: %@", error );
                } else {
                    NSLog( @"Wrote image with metadata to Photo Library %@", newURL.absoluteString);

                    FBSDKShareDialog *dialog = [[FBSDKShareDialog alloc] init];

                    if ([[UIApplication sharedApplication] canOpenURL:[NSURL URLWithString:@"fbauth2://"]]){
                        dialog.mode = FBSDKShareDialogModeNative;
                    }
                    else {
                        dialog.mode = FBSDKShareDialogModeAutomatic;
                    }

                    dialog.fromViewController = self;

                    FBSDKShareVideo *video = [[FBSDKShareVideo alloc] init];
                    video.videoURL = newURL;

                    FBSDKShareVideoContent *content = [[FBSDKShareVideoContent alloc] init];
                    content.video = video;

                    dialog.shareContent = content;
                    dialog.delegate = self;
                    [dialog show];
                }
            };

            if ([library videoAtPathIsCompatibleWithSavedPhotosAlbum:tempURL])
            {
                [library writeVideoAtPathToSavedPhotosAlbum:tempURL
                                            completionBlock:videoWriteCompletionBlock];
            }

我不想将视频保存到相册中。有没有办法避免这个??