Well... That was interesting. I have a 5 gamepads, but none of them are bluetooth, so I've connected them to my phone through the USB->MicroUSB adapter.
1. X360 controller. No response at all. It looks like GM for android isn't supporting xinput at all.
2-3. Two different cheap dinput-only gamepads. No response. Looks like those models aren't supported by GM, because Windows version can't detect them too.
4. PS2 Dualshock. I've connected it through the PS2->USB->MicroUSB chain... No response. I wasn't surprised.
5. PS3 Dualshock. ONE. FUCKING. BUTTON. Only one button (L3) worked as the "Start" button. Nothing more... I don't know how to react to it. My game using 11 out of 16 available gamepad buttons (UDLR,ABX,SL,ST,LB,RB) so the problem isn't with the mapping.
At the end, I've connected my USB keyboard through the same adapter. That was fucked-up experience, only arrow keys worked as they should, everything else was remapped randomly through the whole keyboard.
I've lack of any bluetooth devices, so I can't say where the problem is. But for now I haven't any wish to get into it, so I will leave the controls as they are.