android - Where to put Firebase.setAndroidContext() function

Question

I'm trying to play a bit with Firebase and Android.
I have one RegisterActivity, and one MainActivity. My current flow is - start with MainActivity - check if user is registered, if not, call RegisterActivity - after registeration call MainActivity.

I'm having trouble with where to put the Firebase.setAndroidContext() call.
I have 2 questions:

1. Should I only call this function once in Application or once in each Activty?
2. If the answer for question 1 is only once, then where should I put it ?

Thank you all, Giora.

Answer 1

Waitting for answers