Is it possible to create turn-by-turn GPS navigation app on Android iOS using Google Maps

Question

Today I've talked to a client and he wants to build a simple navigation APP on Android!

Basically we could use Google maps, place some of "our" markers to show some locations (restaurants, hotels etc.) .. also we need to show user's friends near by!

Everything of that is possible in Google Maps API on Android, except I can not find any useful information about Turn-by-turn navigation implementation inside my own app (without switching to Google Maps App) ..

Can someone simply clarify - is it possible to use Google Maps inside an Android app to create turn-by-turn GPS based app?

thanks