I have a pretty basic app that uses Firebase.io for user authorization. I've found some things on how to set up so you can recognize returning users and start them on a different screen as first time users by setting a Boolean value in getSharedPreferences.
I've seen apps that do this, like Discover (a banking app) allows you to set up a 4 digit pin to login with instead of always entering your username and password.
Does anyone know how this is achieved, where I can look for a tutorial or more info on it?
My first idea was that you would store the pin in getSharedPreferences but I couldn't find anything about that and I'm not sure how secure that would be.