May i please have advise on how to add an audio file in a custom activity.
@user_#443444 maybe this will help https://www.w3schools.com/html/html5_audio.asp
or you can use Audio Player activity
I used to include audio in custom activities by adding HTML5 code. But from one moment to another, my users couldn't play more than two times the audio files (they were on an external server). I think the problem was on one Android update (not Andromo). So I decided to use the audio player activity and rebuild all my apps. At the moment I have no more problems with audio. My advice, use the audio player activity, it's better.