I am kind of suprised noone has mentioned Mycelium (https://play.google.com/store/apps/details?id=com.mycelium.wallet) yet.

Mycelium was the best android wallet for quite some time.
Unfortunately they have decided to support some shady russian ICO and to develop a bcash module instead of integrating segwit.
But it still works flawlessly for me (even tho some users report they have connection issues with mycelium). Has a nice UI too.

Other options would be electrum for android and coinomi.