How to control page display to PDF loaded in UIWebView for iOS (go to page)

Question

I'm developing an app which displays a PDF embedded in a WebView this is my code:

- (void)viewDidLoad
{
    [super viewDidLoad];

    NSURL *urlremoto = [NSURL URLWithString:@"https://developer.apple.com/library/ios/documentation/userexperience/conceptual/TransitionGuide/TransitionGuide.pdf"];

    request = [NSURLRequest requestWithURL:urlremoto];

    [self.webView loadRequest:request];
    [self.webView setScalesPageToFit:YES];
}

-(void)webViewDidStartLoad:(UIWebView *)webView{

    [self.activityIndicator startAnimating];
}

-(void)webView:(UIWebView *)webView didFailLoadWithError:(NSError *)error{
    //TODO: describir el error
    [self.activityIndicator stopAnimating];        
}

-(void)webViewDidFinishLoad:(UIWebView *)webView{

    [self.activityIndicator stopAnimating];
}

Now I want to touch a button and change my loaded PDF to certain page, I'm looking for something to achieve this but still got nothing working

thanks in advance for the support

Answer 1

Its late but may be helpful,

For iOS less than 11.0

func webViewDidFinishLoad(_ webView: UIWebView)
    {

        var pdfPageHeight:CGFloat = 0

        let a = webView.scrollView.subviews

        for var view in a
        {
            if view.isKind(of: NSClassFromString("UIWebPDFView")!)
            {
                let b = view.subviews

                for var iview in b
                {
                    if iview.isKind(of: NSClassFromString("UIPDFPageView")!)
                    {
                        pdfPageHeight = iview.bounds.size.height

                        break
                    }
                }
            }
        }

        webView.scrollView.setContentOffset(CGPoint(x: 0, y: CGFloat((pagenumber - 1)   + 1 )*pdfPageHeight), animated: true)

    }

For iOS 11 and greater

var pdfdocumentURL: URL?

    @IBOutlet weak var titleLbl: UILabel!
    @IBOutlet weak var pdfview: PDFView!
    var pagenumber = 1



    override func viewDidLoad()
    {
        super.viewDidLoad()
        self.titleLbl.text = titleStr

       let pdfdocument = PDFDocument(url: pdfdocumentURL!)

        pdfview.document = pdfdocument
        pdfview.displayMode = PDFDisplayMode.singlePageContinuous
        pdfview.autoScales = true

        pagenumber = pagenumber - 1
        if let page = pdfdocument?.page(at: pagenumber) {
            pdfview.go(to: page)
        }


    }

Answer 2

At this moment I think you can use two approaches:

1. Use scrollView to 'navigate, through PDF:

   [[webView scrollView] setContentOffset:CGPointMake(0,y) animated:YES];

   // For example, jumping to page 5 in a PDF document with 1000 px page height:

   int selectedPag = 5; // i.e. Go to page 5
   
   float pageHeight = 1000.0; // i.e. Height of PDF page = 1000 px;
   
   float y = pageHeight * selectedPag;
   
   [[webView scrollView] setContentOffset:CGPointMake(0,y) animated:YES];
   

2. Split PDF individual pages.

Answer 3

As far as I know, Safari Kit does not support named destinations (RFC 3778). In other words, if you try this:

<a href="http://www.domain.com/file.pdf#page=3">Link text</a>

in Safari, it will not work.

The only chance for you to jump to a PDF page, as far as I can see, is using a framework like Reader, or other equivalent.