Send file to webviewer with .apk

I am preparing an app to visualize .gpx files.
I send the .gpx files to the webviewer over the map.
I have no problems with AI Companion, with these blocks it works perfectly.

But when I generate the .apk, I can't open the file.
I have tried with file:///android_asset
But I have not been able to send the file.
Any idea?