Is it a good design pattern, in this case for Android, to persist the application state for wherever the user is, or should this be done just for the first level of depth?
Generally its not good to save the state because the user can get confused easily. But for a shopping list app, it might be a good idea.
When I go out for shopping, I want to see my list quickly. I'm overwhelmed at the store and my hands are already busy picking things. I'd appreciate if the saved state can save me a button press or two.
Btw I can't imagine a deep hierarchy for a shopping list app. There could be categories of lists and that's all; even sub-categories would be too much in my opinion. I'd reckon you save the state. But do keep a button to go back to the top level.