Our team develops mobile applications using Xamarin, and recently one of our customers requested an SDK to create "white labeled" version of our app (with our core functionality, but their design, look and feel). Usually we would pack our core functionality in a library and give it to our partners. However they don't want to use Xamarin, they have no experience in C# and want to develop fully native Android application in Java.
Is there any possibility for us other than rewrite all our code in Java/C++? Is there a way to attach C# library to native Android app?
Or maybe they could use Xamarin app, but write UI code in Java?
I know that was asked before, but maybe something changed since then https://forums.xamarin.com/discussion/45884/using-xamarin-only-to-build-a-portable-library