java - How to call a method only when the app has been launched? Please see details -

i have method in i'm fetching user's details , data firebase database.

the problem method getting called twice or thrice after launching app , again when i'm navigating other activity.

i have put method in oncreate method this:

@override     protected void oncreate(bundle savedinstancestate) {         super.oncreate(savedinstancestate);         setcontentview(r.layout.activity_main);         toolbar toolbar = (toolbar) findviewbyid(r.id.toolbar);         setsupportactionbar(toolbar);          checkauthstate();     } 

i sure haven't called checkauthstate() in onstart() or onresume() methods.

this how i'm navigating other activity:

@override     public boolean onoptionsitemselected(menuitem item) {         switch (item.getitemid()) {             case android.r.id.home:                 onbackpressed();                 return true;         }         return super.onoptionsitemselected(item);     } 

please let me know why checkauthstate() getting called thrice , why getting called again when navigating other activity , how call method once when app has been launched?

sorry if question seems badly formatted. i'm still beginner!

create launcher activity checkauthstatus. start new activity , kill launcher activity.