I am currently using Titanium.Media.AudioPlayer to play audio in my app. I am using the following module to allow control of said audio from the lock screen / homescreen in iOS:
https://github.com/hoyo/TiRemoteControl
Is there an Android equivalent of this solution for Titanium? A module perhaps? Or has anyone managed to get this to work using Hyperloop?
As far as I know it is not possible with the native SDK and there is no (opensource) module. You can try it with Hyperloop (might work) or create a custom Android module yourself (better solution). Have a look at the RemoteControlClient (deprecated in 21) / MediaSession API and this thread: Media Control on Lock Screen like Google Play Music in android?
Another solution would be to ask in the tislack.org/ #job section to find a dev who can create the module for you