How can I write a file in a folder located at Apple's Files App in SwiftUI?

Question

I followed the Swift project UsingFiles github and its video to write files in my SwiftUI project. The project UsingFiles can write files to Files APP and then the writing files

Answer 1

I used UIActivityViewController to save a file on my phone. It's simple and works.

import SwiftUI

struct ContentView: View {

    var body: some View {
        Button(action: wirtieFile) {
            Image(systemName: "square.and.arrow.up")
        }
    }

    func wirtieFile() -> Void{
        let file = "test.txt"
        let dir = NSURL(fileURLWithPath: NSTemporaryDirectory()).appendingPathComponent(file)
        let contents = "test..."
        do {
           try contents.write(to: dir!, atomically: true, encoding: .utf8)
        } catch {
           print(error.localizedDescription)
        }
        var filesToShare = [Any]()
        filesToShare.append(dir!)
        let av = UIActivityViewController(activityItems: filesToShare, applicationActivities: nil)
        UIApplication.shared.windows.first?.rootViewController?.present(av, animated: true, completion: nil)
    }
}