UIKit: Create a UIImage snapshot and use it as thumbnail in a shareSheet

Question

I'm implementing snapshot sharing in iOS app, so the UIImage is created from the View and it is in the sharesheet and works fine, but I can't get to show this UIImage as a thumbnail is ShareSheet.

func actionSheet(image: UIImage) {
        let urlShare = image
        let activityVC = UIActivityViewController(activityItems: [urlShare], applicationActivities: nil)
        UIApplication.shared.windows.first?.rootViewController?.present(activityVC, animated: true, completion: nil)
    }

the UIImage is created on the fly, so there's no url for it in the app

How can I make it show it anyway?

Answer 1

got a great answer to my question from: Jake Bloom: Using Share Sheets on iOS and Android

import Foundation
import SwiftUI
import LinkPresentation

class ShareImage: UIActivityItemProvider {
  var image: UIImage

  override var item: Any {
    get {
      return self.image
    }
  }

  override init(placeholderItem: Any) {
    guard let image = placeholderItem as? UIImage else {
      fatalError("Couldn't create image from provided item")
    }

    self.image = image
    super.init(placeholderItem: placeholderItem)
  }

  @available(iOS 13.0, *)
  override func activityViewControllerLinkMetadata(_ activityViewController: UIActivityViewController) -> LPLinkMetadata? {

    let metadata = LPLinkMetadata()
    metadata.title = "Result Image"

    var thumbnail: NSSecureCoding = NSNull()
    if let imageData = self.image.pngData() {
      thumbnail = NSData(data: imageData)
    }

    metadata.imageProvider = NSItemProvider(item: thumbnail, typeIdentifier: "public.png")

    return metadata
  }

}

and then:

func actionSheet(image: UIImage?) {
        guard let data = image else { return }
        let item = ShareImage(placeholderItem: data)
        let activityViewController = UIActivityViewController(activityItems: [item], applicationActivities: nil)
        
        UIApplication.shared.windows.first?.rootViewController?.present(activityViewController, animated: true, completion: nil)
    }