Implement Document Picker in swift (iOS)

Update for iOS 14: You do not need any capabilities. Just create a UIDocumentPickerViewController with the appropriate types, implement the delegate, and you are done.

More info in this answer. Code from there:

import UIKit
import MobileCoreServices
import UniformTypeIdentifiers

func selectFiles() {
    let types = UTType.types(tag: "json", 
                             tagClass: UTTagClass.filenameExtension, 
                             conformingTo: nil)
    let documentPickerController = UIDocumentPickerViewController(
            forOpeningContentTypes: types)
    documentPickerController.delegate = self
    self.present(documentPickerController, animated: true, completion: nil)
}

---

From your project’s capabilities, enable both the iCloud and the Key-Sharing.

Import MobileCoreServices in your class and then extend the following three classes inside your UIViewController:

UIDocumentMenuDelegate,UIDocumentPickerDelegate,UINavigationControllerDelegate

Implement the following functions:

public func documentPicker(_ controller: UIDocumentPickerViewController, didPickDocumentsAt urls: [URL]) {
    guard let myURL = urls.first else {
        return
    }
    print("import result : \(myURL)")
}
      

public func documentMenu(_ documentMenu:UIDocumentMenuViewController, didPickDocumentPicker documentPicker: UIDocumentPickerViewController) {
    documentPicker.delegate = self
    present(documentPicker, animated: true, completion: nil)
}


func documentPickerWasCancelled(_ controller: UIDocumentPickerViewController) {
    print("view was cancelled")
    dismiss(animated: true, completion: nil)
}

How do you call all of this? Add the following bit of code to your click function:

func clickFunction(){

let importMenu = UIDocumentMenuViewController(documentTypes: [String(kUTTypePDF)], in: .import)
    importMenu.delegate = self
    importMenu.modalPresentationStyle = .formSheet       
    self.present(importMenu, animated: true, completion: nil)
}

Click your button. The following menu will pop up ..

In the case of Dropbox. Upon clicking on any item. You will be redirected back to your app and the URL will be logged in your terminal.

Manipulate the documentTypes to your need. In my app, Users permitted to Pdf only. So, suit yourself.

kUTTypePDF
kUTTypePNG
kUTTypeJPEG
…

Also if you feel like customizing your own menu bar. Add the following code and customize your own function inside the handler

importMenu.addOption(withTitle: "Create New Document", image: nil, order: .first, handler: { print("New Doc Requested") })

Enjoy it.