android - Show Google Play Games Welcome Dialog on all app launches - Stack Overflow

The best example of what I am trying to attempt can be described by the behavior of the simcity app (and I'm sure many others that I may be unaware of also using the google sign in for Google play

Building an Awesome Login Screen with NativeScript

android - Google Play in-app purchase app icon not shown - Stack Overflow

android - When opening dialog activity, the launcher activity always shows below if in the stack - Stack Overflow

Planet Mozilla

java - Overlay Android AlertDialog with a View (Button) - Stack Overflow

In-App Purchases with Flutter: A Comprehensive Step-by-Step tutorial, by M4trix Dev, Flutter Community

Why do people install the 3rd party app market in Android if there is a Play Store in Android? - Quora

android-6-for-programmers-3rd

Per-app language preferences

android - How to launch the Google Play Store as a popup - Stack Overflow