I have an iOS App that uses an UIActivityViewController to share files. It works perfectly on iPad, iPhone and on Mac using (Made for iPad). But when I test the Mac Catalyst app it works perfectly except "Save" and "Copy" are missing from the Share Panel. I think it must be an issue with entitlements and the sandbox. I have tried every folder location available from FileManager.default. If I send the file content as Data rather than a URL that only works on iPad/iPhone while Mac Catalyst share panel shows no options at all.

I tried using url.startAccessingSecurityScopedResource() but that always returned false and made no difference.

I have set the App Sandbox entitlements to Read/Write for User Selected File.

There must be a location where I can save the temporary file and the Share Panel can access it for file Save and Copy actions? Any ideas on the file path? Thanks

Here is the code.

// dataToShare is initialised with the actual data for the file to export, 
// before the UIActivityViewController is called
// data is presented to the UIActivityViewController using UIActivityItemSource
    var dataToShare = Data()

func proceedToShare(sender: UIViewController, anchorButton: UIView) {
// activityController is a retained var
    activityController = UIActivityViewController(activityItems: [self], applicationActivities: nil)
    activityControllerpletionWithItemsHandler = {_,_,_,_ in sender.navigationController?.popViewController(animated: true) }
    if UIDevice.current.userInterfaceIdiom == .pad {
        // also MacCatalyst and madeForIpad
        activityController.popoverPresentationController?.sourceView = anchorButton
        activityController.modalPresentationStyle = .popover
    } else {
        activityController.isModalInPresentation = true
    }
    sender.present(activityController, animated: true)
}


func activityViewController(_ activityViewController: UIActivityViewController, itemForActivityType activityType: UIActivity.ActivityType?) -> Any? {
    return fileContentForExport()
}

func fileContentForExport() -> Any {
    if  ProcessInfo().isMacCatalystApp {
    /* This is called for both MacCatalyst and iOS (designed For iPad apps) */
        let directoryURL = FileManager.default.temporaryDirectory
        let filename = "ExportFile.txt"
        let fileURL = directoryURL.appendingPathComponent(filename))
        do {
            try dataToShare.write(to: fileURL)
            return fileURL
        } catch let error { print(error.localizedDescription) }
    }
    /* iPhone and iPad on iOS handle data directly */
    return dataToShare
}