Why my WKWebview or PDFViewer only works in iPhone XR simulator

Question

I have local pdf files in a document directory. My code calls each one to display using WKWebview or PDFViewer , but it only shows on an iPhone XR simulator, but not on any other simulator devices.

Any devices which are older than XR, it shows an error:

libMobileGestalt MobileGestalt.c:890: MGIsDeviceOneOfType is not supported on this platform.

Devices with XS, XS Max, it shows the error:

failed to open pdf ...

as seen in the code.

Does anyone know why?

I use Xcode 10.2.

Here is the code that I use for WKWebviewer

    @IBOutlet weak var webView: WKWebView!
    //only work on XR, don't know why
    override func viewDidLoad() {
        super.viewDidLoad()

        let documentDir = FileManager.SearchPathDirectory.documentDirectory
        let userDir    = FileManager.SearchPathDomainMask.userDomainMask
        let paths      = NSSearchPathForDirectoriesInDomains(documentDir, userDir, true)
        if let dirPath = paths.first
        {

            let pdfURL = URL(fileURLWithPath: dirPath).appendingPathComponent("my file.pdf")
            do {
                //only work in Xr 
                let data = try Data(contentsOf: pdfURL)
                webView.load(data, mimeType: "application/pdf", characterEncodingName:"", baseURL: pdfURL.deletingPathExtension())
                //not working for Xs, Xs Max... later iphone
                //webView.loadFileURL(pdfURL, allowingReadAccessTo: pdfURL)
                //webView.load(URLRequest(url:pdfURL))

                //webView.loadFileURL(pdfURL, allowingReadAccessTo: pdfURL)
                print("open pdf file....")

            }
            catch {
                print("failed to open pdf \(dirPath)" )
            }
            return
        }

and for PDFViewer :

let documentDir = FileManager.SearchPathDirectory.documentDirectory
let userDir    = FileManager.SearchPathDomainMask.userDomainMask
let paths      = NSSearchPathForDirectoriesInDomains(documentDir, userDir, true)
if let dirPath = paths.first
{

    let pdfURL = URL(fileURLWithPath: dirPath).appendingPathComponent("myfile2.pdf")

    view.addSubview(pdfView)

    pdfView.autoresizesSubviews = true
    pdfView.autoresizingMask = [.flexibleWidth, .flexibleHeight, .flexibleTopMargin, .flexibleLeftMargin]
    pdfView.displayDirection = .vertical

    //pdfView.autoScales = true

    pdfView.displayMode = .singlePageContinuous
    pdfView.displaysPageBreaks = true

    if let document = PDFDocument(url: pdfURL) {
        pdfView.document = document
    }

    pdfView.maxScaleFactor = 4.0
    pdfView.minScaleFactor = pdfView.scaleFactorForSizeToFit

Answer 1

Matt helps me to find out the problem. Thank you Matt. Please see the comments. Each iOS device in simulator has different folder id. When you download to a device simulator document directory, do not expect it could find the same for another simulator device in the same document directory.