AngularJS basics from W3School
Android Firebase - How to allow user to sign in with their google account?
Please find the steps for integrating Firebase-google-sign-in using Android studio.
Android Basics - How to show back button on an Activity?
You should have at-least two activities.
Android Basics - How to use Timer to show splash screen?
Here, I’ve created an example of a splash creen just like
LaunchScreen.storyboard for iOS.
It stays on screen for 3 seconds & it shows login screen. One can refer following example to implement similar spash screen in his/her/their android application.