How do I give screenshot file a filename when sharing via UIActivityView - swift

Question

I have created a VC with a print and share friendly version of a bunch of calculations. When I press "share" there appears the little icon and all the share options which is great. I cannot figure out how to add a filename of some kind beside the little icon. I think this would look much more professional if I could get this accomplished.
Hope there is a simple solution someone could help with :)
Here is my code:
import UIKit
class EvenPrintableViewController: UIViewController {
#IBOutlet weak var widthSizeTransfer: UILabel!
#IBOutlet weak var heightSizeTransfer: UILabel!
#IBOutlet weak var lengthTransfer: UILabel!
#IBOutlet weak var calcOutput: UILabel!
// Instantiate variables for Even transfer
var largeSizeRelay: String?
var lengthSizeRelay: String?
var heightRelay: String?
var calcOutputRelay: String?
override func viewDidLoad() {
super.viewDidLoad()
// Sets share icon to share/print view
navigationItem.rightBarButtonItem = UIBarButtonItem(barButtonSystemItem: .action, target: self, action: #selector(shareTapped))
// Assign labels to Metric Even VC values via instances above
widthSizeTransfer.text = witdhSizeRelay
heightSizeTransfer.text = heightSizeRelay
heightTransfer.text = heightRelay
calcOutput.text = calcOutputRelay
}
// Share function for share button
#objc func shareTapped() {
let renderer = UIGraphicsImageRenderer(size: view.bounds.size)
let image = renderer.image { ctx in
view.drawHierarchy(in: view.bounds, afterScreenUpdates: true)
}
let vc = UIActivityViewController(activityItems: [image], applicationActivities: [])
vc.excludedActivityTypes = [.assignToContact, .addToReadingList]
vc.popoverPresentationController?.barButtonItem = navigationItem.rightBarButtonItem
present(vc, animated: true)
}
}

Answer 1

First save the UIImage as a temporary png/jpg file:
guard let imageData = image.pngData() else { return }
Then save it as a temporary file, which lets you to choose a file name:
let tempDir = FileManager.default.temporaryDirectory
let imgFileName = "YOUR_IMG_FILE_NAME.png"
let tempImgDir = tempDir.appendingPathComponent(imgFileName)
try? imageData.write(to: tempImgDir)
Then you can share the URL instead:
// Your code
let vc = UIActivityViewController(activityItems: [tempImgDir], applicationActivities: [])
P.S. the file is only temporary.