How to display pdf offline in Xamarin.Forms apps?

[GoldenGlitterBug]

Using PDFJS for displaying PDF files in a Xamarin.Forms apps. Copied the PDFJS folder and PDF files to the android assets folder. I am able to view/display PDFs on Android and iOS when online (connected to internet or mobile service).

But when I am offline I get following error:
"Access to XMLHttpRequest at 'file:///android_asset/abcd.pdf' from origin 'null' has been blocked by CORS policy: Cross origin requests are only supported for protocol schemes: http, data, chrome, https.", source: file:///android_asset/pdfjs/web/viewer.js

My code:

page.xaml

<WebView
    x:Name="webView"
    BackgroundColor="White"
    HorizontalOptions="FillAndExpand"
    VerticalOptions="FillAndExpand"
    Margin="20">           
</WebView>

page.xaml.cs

if (Device.RuntimePlatform == Device.Android)
{
      string localPath = "file:///android_asset/abcd.pdf";
      webView.Source = $"file:///android_asset/pdfjs/web/viewer.html?file={WebUtility.UrlEncode(localPath)}";
}
else
     webView.Source = Path.Combine(DependencyService.Get<IBaseUrl>().Get(), "abcd.pdf"); 

PdfWebViewRenderer.cs

[assembly: ExportRenderer(typeof(PdfWebView), typeof(PdfWebViewRenderer))]
namespace MobileApp.Droid.Scripts
{
	public class PdfWebViewRenderer : WebViewRenderer
	{
		public PdfWebViewRenderer(Context context) : base(context)
		{
		}

		protected override void OnElementChanged(ElementChangedEventArgs<WebView> e)
		{
			base.OnElementChanged(e);

			if (e.NewElement != null)
			{
				Control.Settings.AllowFileAccess = true;
				Control.Settings.AllowFileAccessFromFileURLs = true;
				Control.Settings.AllowUniversalAccessFromFileURLs = true;
			}
		}

		// If you want to enable scrolling in WebView uncomment the following lines.
		//public override bool DispatchTouchEvent(MotionEvent e)
		//{
		//    Parent.RequestDisallowInterceptTouchEvent(true);
		//    return base.DispatchTouchEvent(e);
		//}
	}
}

I am using pdf.js (https://github.com/timvandermeij/pdf.js) October 2020 version. Does this work Offline when mobile not connected to internet? My requirement is to display PDF from asset folder 'file:///android_asset/abcd.pdf' when user is Offline..

Also when I try to download the latest stable version(v2.12.313) or any other previous version I get lots of errors.

How to resolve this error or display PDF Offline in Xamarin.Forms Android and iOS apps?

[jingliancui]

For Android you can use this https://www.nuget.org/packages/XamarinLibrary.Xamarin.Android.Github.Barteksc.AndroidPdfViewer/

For iOS you can use pdfkit.

[GoldenGlitterBug]

Thanks. From online reviews it's not very efficient. Namarata Chaturvedi Get Outlook for Android<https://aka.ms/AAb9ysg>

…

________________________________ From: jingliancui ***@***.***> Sent: Monday, February 7, 2022 10:01:19 AM To: xamarin/Xamarin.Forms ***@***.***> Cc: GGBG ***@***.***>; Author ***@***.***> Subject: Re: [xamarin/Xamarin.Forms] How to display pdf offline in Xamarin.Forms apps? (Discussion #15099) For Android you can use this https://www.nuget.org/packages/XamarinLibrary.Xamarin.Android.Github.Barteksc.AndroidPdfViewer/ For iOS you can use pdfkit. — Reply to this email directly, view it on GitHub<#15099 (comment)>, or unsubscribe<https://github.com/notifications/unsubscribe-auth/ANS6RO6JLN3MDYCWBZVW7RDUZ7UE7ANCNFSM5M3SO2CQ>. Triage notifications on the go with GitHub Mobile for iOS<https://apps.apple.com/app/apple-store/id1477376905?ct=notification-email&mt=8&pt=524675> or Android<https://play.google.com/store/apps/details?id=com.github.android&referrer=utm_campaign%3Dnotification-email%26utm_medium%3Demail%26utm_source%3Dgithub>. You are receiving this because you authored the thread.Message ID: ***@***.***>