would xbox controller work

[FatFingerz]

The controller DOESN'T need to be recognized by PPSSPP, as long as you're using an IME app that maps the inputs to the device's native inputs.
I suggest you try "USB/BT Joystick Center Gold" out, one of the best IME app on the Android market which support a wide range of controllers. (You need to pay for it though, like 6-7 bucks)