bluetooth AR gun with android

hello all, i was wondering if anyone can shed light on how i might go by assigning buttons on a bluetooth gun controller to work with an android device? the phone recognises the bluetooth device, but unity regular controller inputs dont work., such as jump, space, joystick button # etc. Im having no luck assigning the fire trigger to be recognised in a unity app i'm building. I was putting feelers out to see if anyone has a line of code that works on generic bluetooth buttons?