How to detect scrolling to another page in PDF using PDFkit - swift

Question

I'm trying to add current page number
so when the user scrolling to another page it will display
for example
2 of 3 (if the pdf have 3 pages)
for now, I use this code
it will display always 1 of 3
I think PDFkit using UIScrollView
so I need to reach to the ScrollView that way I could detect when scrolling to another page and then increase the current page number
I didn't find any way to reach to scrollview in PDFkit
func showCurrentPageIndex(){
guard let totalPages = pdfContainerView.document?.pageCount else {return}
guard let currentPage = pdfContainerView.currentPage else {return}
guard let currentPageRef = currentPage.pageRef else {return}
let pageIndex = currentPageRef.pageNumber
totalPageNumbers.text = "\(totalPages)"
currentPageIndex.text = "\(pageIndex)"
}

Answer 1

Use a notification (PDFViewPageChanged).
import UIKit
import PDFKit
class ViewController: UIViewController, PDFViewDelegate {
// MARK: - Variables
var totalCount = Int()
// MARK: - IBOutlet
#IBOutlet weak var pdfView: PDFView!
// MARK: - Life cycle
override func viewDidLoad() {
super.viewDidLoad()
let filePath = "Some file document path"
pdfView.document = getDocument(path: filePath)
if let total = pdfView.document?.pageCount {
totalCount = total
}
pdfView.backgroundColor = .lightGray
pdfView.autoScales = true
pdfView.displayMode = .singlePageContinuous
pdfView.usePageViewController(true, withViewOptions: nil)
}
override func viewDidAppear(_ animated: Bool) {
super.viewDidAppear(animated)
/* notification */
NotificationCenter.default.addObserver (self, selector: #selector(handlePageChange), name: Notification.Name.PDFViewPageChanged, object: nil)
}
func getDocument(path: String) -> PDFDocument? {
let pdfURL = URL(fileURLWithPath: filePath)
let document = PDFDocument(url: pdfURL)
return document
}
}