UIDocumentPickerViewController - didPickdocumentsAt

Question

Hey,

I have been working with the UIDocumenPickerViewController in the last few days.

This is my current code:

let documentPicker = UIDocumentPickerViewController(documentTypes: [kUTTypePlainText as String], in: .open) 
documentPicker.delegate = self
     
if #available(iOS 11.0, *) 
{
   documentPicker.allowsMultipleSelection = false
} 
else { }
present(documentPicker, animated: true, completion: nil)

Now my question: After this code I call the didPickDocumentAt Methode

documentPicker(, didPickDocumentsAt: )

But I have no idea what I should put in it, I tried it like this

documentPicker(documentPicker, didPickDocumentsAt: [UIDocumentPickerMode.open])

I tried it like this but then I always get the Error: Cannot call value of non-function type 'UIDocumentPickerViewController'

And my second question is: I want to acces the content of the selected File and found this in the documentation https://developer.apple.com/documentation/uikit/view_controllers/providing_access_to_directories

If you go to Access the Directory´s content you find this code

// Start accessing a security-scoped resource.
guard url.startAccessingSecurityScopedResource() else {
  // Handle the failure here.
  return
}

// Make sure you release the security-scoped resource when you are done.
defer { url.stopAccessingSecurityScopedResource() }

// Use file coordination for reading and writing any of the URL’s content.
var error: NSError? = nil
NSFileCoordinator().coordinate(readingItemAt: url, error: &error) { (url) in
   
  let keys : [URLResourceKey] = [.nameKey, .isDirectoryKey]
   
  // Get an enumerator for the directory's content.
  guard let fileList =
  FileManager.default.enumerator(at: url, includingPropertiesForKeys: keys) else {
  output.append("*** Unable to access the contents of \(url.path) ***\n")
  return
  }
   
  for case let file as URL in fileList {
  // Also start accessing the content's security-scoped URL.
  guard url.startAccessingSecurityScopedResource() else {
  // Handle the failure here.
  continue
  }
   
  // Make sure you release the security-scoped resource when you are done.
  defer { url.stopAccessingSecurityScopedResource() }

  // Do something with the file here.
  }
}

Where do they get the url from in the beginning? The documentation never explains where the url got created.

Thank you for your help

Regards,

Tell

Swift

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Answer 1

Have you noticed this line?

documentPicker.delegate = self

This means your `UIViewController` needs to conform to `UIDocumentPickerDelegate`.

And the method `documentPicker(_:didPickDocumentsAt:)` defined in the protocol `UIDocumentPickerDelegate`,

it is not a method you call, but iOS calls it when user did pick a document (documents) with the picker.

You need to define the method and write code describing what to do when user picked documents, the method receives `urls` from iOS.

    func documentPicker(_ controller: UIDocumentPickerViewController, didPickDocumentsAt urls: [URL]) {
        //An example...
        for url in urls {
            //`url` holds the url of an actual document chosen, which may be a file: url.
            //...
        }
    }

You may need to replace line 05. of my code with the code Access the Directory´s content.

(Some modification may be needed as the original code shown is written for a single `url`.)

Posted by

OOPer

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Answer 2

Have you noticed this line?

documentPicker.delegate = self

This means your `UIViewController` needs to conform to `UIDocumentPickerDelegate`.

And the method `documentPicker(_:didPickDocumentsAt:)` defined in the protocol `UIDocumentPickerDelegate`,

it is not a method you call, but iOS calls it when user did pick a document (documents) with the picker.

You need to define the method and write code describing what to do when user picked documents, the method receives `urls` from iOS.

    func documentPicker(_ controller: UIDocumentPickerViewController, didPickDocumentsAt urls: [URL]) {
        //An example...
        for url in urls {
            //`url` holds the url of an actual document chosen, which may be a file: url.
            //...
        }
    }

You may need to replace line 05. of my code with the code Access the Directory´s content.

(Some modification may be needed as the original code shown is written for a single `url`.)

Posted by

OOPer

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UIDocumentPickerViewController - didPickdocumentsAt

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