Checking authorization in the application?

Question

Android

Hello. I am creating an application in which the user must log in before getting to the main screen. How to check whether the user is logged in or not before launching the activity?

Answer 1

What is the question is the answer:
if (isUserAuthorized == true)
In fact: you would write how you authorize it, who checks the correctness of the login / password. Maybe you do it through some kind of Facebook ...

Answer 2

As an example: after entering the login/password pairing, the client receives a temporary API key. Got a key? So you can continue to work, send requests and receive responses.