hi,
you are so lucky, I just survey some interesting mobile GIS app and share my ideas for your reference. there are many mapping apps on Google playstore, such as: SuperSurv, WolfGIS, ArcGIS, PDF Maps...and so on.
I will suggest to use SuperSurv which i love it.. it's great. this app could be an extremely convenient tool. I tested this on Forest field and i found it to be very accurate and easily use, reliable GPS, stable signal, multitude of great features built into the app as well.
it's excellent tool.