37.5 Summary

A well designed app should always present the user with the same state when brought forward from the background, regardless of whether the process containing the app was terminated by the operating system in the interim. When working with ViewModels this can be achieved by taking advantage of the ViewModel Saved State module. This involves modifying the ViewModel constructor to accept a SavedStateHandle instance which, in turn, can be used to save and restore data values via a range of method calls. When the ViewModel instance is created, it must be passed a SavedStateViewModelFactory instance. Once these steps have been implemented, the app will automatically save and restore state during a background termination.