Can the same instance of ViewModel be used in different parts of an application implementing the MVVM pattern?

In the Android MVVM pattern, usually each screen or fragment has its own instance of ViewModel to manage the state and logic of that specific UI component. However, if needed, the same ViewModel instance can be used across different parts of the application, for example, when using a ViewModel associated with the Activity's lifecycle, and sharing data between multiple fragments within that Activity.

This is done using ViewModelProvider with the Activity as the owner:

val sharedViewModel = ViewModelProvider(requireActivity()).get(SharedViewModel::class.java)

Thus, the ViewModel will be shared among all fragments within the Activity, allowing data and state exchange.

However, using the same ViewModel across unrelated parts of the application (e.g., different Activities) is not recommended, as it can lead to memory leaks and lifecycle management issues.