How to ensure the preservation of ViewModel state during screen transitions?

To preserve the state of a ViewModel during screen transitions in Android, it is recommended to use SavedStateHandle. This is a special object that allows saving and restoring ViewModel data upon recreation, such as during screen rotation or navigation.

Example of usage:

class MyViewModel(private val savedStateHandle: SavedStateHandle) : ViewModel() {
    var userName: String?
        get() = savedStateHandle["userName"]
        set(value) {
            savedStateHandle["userName"] = value
        }
}

When navigating via the Navigation Component, you can pass arguments that are automatically saved in SavedStateHandle. This way, the ViewModel's state is preserved and restored without additional code.

If the ViewModel is created manually, you can use ViewModelProvider with SavedStateViewModelFactory to support state preservation.