How to set maximum files to select in UIDocumentPickerViewController - ios

Question

I need to set a number of files that can be selected by enabling the UIDocumentPickerViewController allowsMultipleSelection, but I didn't find any properties that I could use to set this.
It is possible?

Answer 1

In order to do this, you'll need to implement UIDocumentPickerDelegate's didPickDocumentsAt. It would look something like this:
class YourViewController: UIDocumentPickerViewController {
let maxDocs = 3
override func viewDidLoad() {
super.viewDidLoad()
delegate = self
}
}
extension YourViewController: UIDocumentPickerDelegate {
func documentPicker(_ controller: UIDocumentPickerViewController, didPickDocumentsAt urls: [URL]) {
// check to make sure you haven't hit your document cap specified above
guard urls.count < maxDocs else { return }
// if you pass the guard, business as usual
}
}
I haven't worked with this class before, so there may be some rough edges, but that's the physics for poets way of how you'd do it. You may need to refine it a bit, as I'm not sure where the URLs for the delegate method come from. You could throw in a breakpoint when this method is called and do po urls to see what's in there.
In looking at the delegate methods available for this class, I don't see one for selecting an individual document, so you'll need to tinker around to see what happens with the array of URLs that's a parameter in the delegate method and figure out how much bookkeeping you need to do to handle state toggling between selected and !selected.

Answer 2

You'll need to use :
UIDocumentBrowserViewController
instead of UIDocumentPickerViewController. It will allow you to select multiple items :
let document = UIDocumentBrowserViewController(forOpeningFilesWithContentTypes: ["public.text", "com.apple.iwork.pages.pages", "public.data"])
func documentBrowser(_ controller: UIDocumentBrowserViewController, didPickDocumentsAt documentURLs: [URL]) {
print("result.........\(documentURLs)")
}
override func viewDidLoad() {
super.viewDidLoad()
document.delegate = self
document.allowsPickingMultipleItems = true
}
And don't forget to add UIDocumentBrowserViewControllerDelegate to your VC.