ios - Can I get a NSURL from an XCAssets bundle?

Question

I'm in a situation where I am listing attachments from a message. Each attachment has a NSURL associated with it that represents a path to the attachment data. In the case of non-image attachments I want to load pre-generated icon thumbnails in the place of a preview (i.e. excel documents, PDF, word, etc).

I currently have these images in my project, within an XCAssets bundle. I can get at them using [UIImage imageNamed:@"someName"]. I cannot seem to get at them via NSBundle's various resource lookup methods. Does the XCAssets bundle somehow change the filenames of the icon images I'm looking for?

Here's the code I'm currently working with. Path is nil every time. Do I need to not use XCAssets in this case?

+ (NSURL *)mediaURLWithMessage:(SRMediaMessage*)message
{
  NSURL *url = message.mediaURL;

  // if this is an image URL or non-existant, there is no work left to do, return it.
  if (!url || (message.secureFile.secureFileMimeType & SRSecureFileMimeTypeImage))
    return url;

  NSString *filename = @"unknown";

  switch (message.secureFile.secureFileMimeType)
  {
    case SRSecureFileMimeTypeDOC:
      filename = @"doc";
      break;

    case SRSecureFileMimeTypePPT:
      filename = @"ppt";
      break;

    case SRSecureFileMimeTypePDF:
      filename = @"pdf";
      break;

    case SRSecureFileMimeTypeXLS:
      filename = @"exl";
      break;

    case SRSecureFileMimeTypeCSV:
      filename = @"csv";
      break;

    case SRSecureFileMimeTypeTXT:
      filename = @"txt";
      break;

    case SRSecureFileMimeTypeRTX:
      filename = @"rtf";
      break;

    default:
    case SRSecureFileMimeTypeMP4:
      // unknown icon for now.
      break;

      // unused but available:
//      @"ilife"

  }

  NSString *path = [[NSBundle mainBundle] pathForResource:filename ofType:nil];
  if (path)
    url = [NSURL fileURLWithPath:path];

  return url;
}

Answer 1

I wanted to access some vector assets for creating UNNotificationAttachment with local resources so I came up with this helper class. It basically just gets image from assets, saves its data to disk and return file URL. I hope that helps someone.

import UIKit

class AssetExtractor {

    static func createLocalUrl(forImageNamed name: String) -> URL? {

        let fileManager = FileManager.default
        let cacheDirectory = fileManager.urls(for: .cachesDirectory, in: .userDomainMask)[0]
        let url = cacheDirectory.appendingPathComponent("(name).png")

        guard fileManager.fileExists(atPath: url.path) else {
            guard
                let image = UIImage(named: name),
                let data = UIImagePNGRepresentation(image)
            else { return nil }

            fileManager.createFile(atPath: url.path, contents: data, attributes: nil)
            return url
        }

        return url
    }

}