.NET MAUI app throws Java.Lang.RuntimeException with Font asset not found /data/user/0/app.xyz/cache/telerikfont.ttf

[Patrick]

We recently discovered that our .NET MAUI APP (8.0.92) throws a Java.Lang.RuntimeException with Font asset not found /data/user/0/app.xyz/cache/telerikfont.ttf.

Here's the full exception detail:

Java.Lang.RuntimeException:
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw (System.Private.CoreLib, Version=8.0.0.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e)
   at Java.Interop.JniEnvironment+StaticMethods.CallStaticObjectMethod (Java.Interop, Version=7.0.0.0, Culture=neutral, PublicKeyToken=84e04ff9cfb79065)
   at Java.Interop.JniPeerMembers+JniStaticMethods.InvokeObjectMethod (Java.Interop, Version=7.0.0.0, Culture=neutral, PublicKeyToken=84e04ff9cfb79065)
   at Android.Graphics.Typeface.CreateFromAsset (Mono.Android, Version=0.0.0.0, Culture=neutral, PublicKeyToken=84e04ff9cfb79065)
   at Microsoft.Maui.FontManager.LoadTypefaceFromAsset (Microsoft.Maui, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null)

 

We do have a "Font" folder in our Application, but in our understanding this shouldn't be a problem anymore.

We register those fonts, which are in the Fonts folder:

.ConfigureFonts(fonts =>
{
	fonts.AddFont("OpenSans-Regular.ttf", "OpenSansRegular");
	fonts.AddFont("OpenSans-Semibold.ttf", "OpenSansSemibold");
	fonts.AddFont("FontAwesomePro-Light-300.otf", "FontAwesomeLight");
	fonts.AddFont("FontAwesomePro-Regular-400.otf", "FontAwesomeRegular");
	fonts.AddFont("FontAwesomePro-Solid-900.otf", "FontAwesomeSolid");
});

In addition to that, we have a custom CustomFontsProvider for the fonts we use in the RadPdfProcessing lib for .NET MAUI. Those fonts are however in the RAW.

public class CustomFontsProvider : Telerik.Windows.Documents.Extensibility.FontsProviderBase
{
    public override byte[] GetFontData(Telerik.Windows.Documents.Core.Fonts.FontProperties fontProperties)
    {
        string fontFileName = fontProperties.FontFamilyName + ".ttf";

        if (fontProperties.FontFamilyName == "Verdana")
        {
            if (fontProperties.FontStyle == FontStyles.Normal && fontProperties.FontWeight == FontWeights.Normal)
            {
                fontFileName = $"Verdana.ttf";
            }
            elseif (fontProperties.FontWeight == FontWeights.Bold)
            {
                fontFileName = $"Verdana-Bold.ttf";
            }
        }

        var fileStream = FileSystem.Current.OpenAppPackageFileAsync(fontFileName).GetAwaiter().GetResult();

        var memoryStream = new MemoryStream();
        fileStream.CopyTo(memoryStream);

        return memoryStream.ToArray();
    }
}
 
How can we resolve this issue? Any support is appreciated. 
 

[Didi]

Hi Patrick,

I tested the scenario in a sample app and cannot reproduce the exception. Could you please send a sample in which the issue happens? 

Check whether you use the Telerik MAUI 8.0.0 version and let me know whether the issue happens in release or debug mode? Also delete bin and obj folders then build the app and test.

Regards,
Didi
Progress Telerik

[Andrey]

Hi Didi, happening with the following config in RELEASE:

<PackageReference Include="Telerik.UI.for.Maui" Version="10.1.0" />

 <RuntimeIdentifier>android-arm</RuntimeIdentifier>
 <PublishTrimmed>true</PublishTrimmed>
 <TrimMode>full</TrimMode>
 <AndroidEnableProfiledAot>false</AndroidEnableProfiledAot>
 <EnableLLVM>true</EnableLLVM>
 <RunAOTCompilation>true</RunAOTCompilation>

[Didi]

Hi Andrey,

We have our Controls Samples app in the stores and such issue does not observe. 

As a next steps: open a support ticket and attach a sample app there, so I can research the case further.

[Jones]

Hi Didi,

I'm also getting the same error when debugging using an Android simulator in a MAUI net9 app, with different versions of Telerik, including the latest one.

Would you please provide a link from which to download it?

Microsoft.Maui.FontManager: Warning: Unable to load font '/data/user/0/com.officecore.officetrackplus/cache/telerikfont.ttf' from assets.

Java.Lang.RuntimeException: Font asset not found /data/user/0/com.officecore.officetrackplus/cache/telerikfont.ttf
   at Java.Interop.JniEnvironment.StaticMethods.CallStaticObjectMethod(JniObjectReference type, JniMethodInfo method, JniArgumentValue* args) in /Users/runner/work/1/s/xamarin-android/external/Java.Interop/src/Java.Interop/obj/Release/net8.0/JniEnvironment.g.cs:line 21453
   at Java.Interop.JniPeerMembers.JniStaticMethods.InvokeObjectMethod(String encodedMember, JniArgumentValue* parameters) in /Users/runner/work/1/s/xamarin-android/external/Java.Interop/src/Java.Interop/Java.Interop/JniPeerMembers.JniStaticMethods.cs:line 165
   at Android.Graphics.Typeface.CreateFromAsset(AssetManager mgr, String path) in /Users/runner/work/1/s/xamarin-android/src/Mono.Android/obj/Release/net9.0/android-35/mcw/Android.Graphics.Typeface.cs:line 637
   at Microsoft.Maui.FontManager.LoadTypefaceFromAsset(String fontfamily, Boolean warning) in /_/src/Core/src/Fonts/FontManager.Android.cs:line 133
  --- End of managed Java.Lang.RuntimeException stack trace ---
java.lang.RuntimeException: Font asset not found /data/user/0/com.officecore.officetrackplus/cache/telerikfont.ttf

[Didi]

Hi Jones,

Could you please open a support ticket and attach a sample app in which the issue happens, so I can further research the behavior. As on my side such exception does not occur. The font mentioned in the exception is our internal font used in the controls, so this font is not shared in the sample apps we have. I can send it via a support ticket, however I want to research why such error occurs on android.

Lets continue the communication in a support ticket.