Android SSO (Single sign-on) for app

Question

Is there any free single-signon mechanism for Android that gracefully works with non-webapps? Say, something along the lines of...

1. You launch my app and use

Answer 1

Use Android Account Manager for SSO.

Providing references below just for knowledge. You have to dig into account manager.
Android developer: https://developer.android.com/training/id-auth
Blog with example: https://www.zoftino.com/android-account-manager-&-create-custom-account-type