Connect and Send Midi messages to multiple connected midi device (USB/bluetooth).

Build you own Midi controler on your phone.

Chain action: each midi button can trigger any other action...

Multiples controlers types: momentary switch, rotary encoders, note,...
Rotary encoders are specials, you can turn them as a pot but also click it, it can then work with multiple midi command, so you can put an infinity of settings on one single controler, clicking it to go to next setting...

Check my other Audio app :

https://play.google.com/store/apps/details?id=com.audio2notes.audio2notes_app&pcampaignid=web_share