The Curious Case of Survival of Android ViewModel

If you are reading this article, then you must have some idea about ViewModels. ViewModels are the latest building blocks of an android app.

According to the official documentation:

The ViewModel class is designed to store and manage UI-related data in a lifecycle conscious way. The ViewModelclass allows data to survive configuration changes such as screen rotations.

Architecture Components provides ViewModel helper class for the UI controller that is responsible for preparing data for the UI. ViewModel objects are automatically retained during configuration changes so that data they hold is immediately available to the next activity or fragment instance.

FYI: You can use ViewModel to preserve UI state only during a configuration change, nothing else as explained perfectly in this official doc. This image summarizes this doc perfectly.

After reading all this I assumed that, OK, then this is how ViewModel works and preserve data during configuration change :

1. ViewModel is a separate class which has an instance of it in the activity and has no reference for view in it.