When should you use an application class?

Question

Android

Here I have ViewModel() and Application(). The UI has onClickListener, it contains a function call that saves key-value data. The function that saves key-value data ( fun saveData(data: Boolean) { }) should be in the ViewModel or in the Application?

Answer 1

Very rarely is it needed. For example, a DI root should grow from it. Also there can be all sorts of specific things, such as initializing the multidex, initializing the crash logging libraries, and loading native libraries.
The saveData function should definitely not be in it.