I'm writing an Android app. The core of its functionality is performing location checks to check if a user is near a certain location. For this question, let that be called home.
The first time it is opened, the user needs to fill out 2-3 pages of simple configurations (one or two clicks per page). I'm planning on making the pages swipeable, with the little circle indicators. One of the pages is the location of home. The user can change the home location in settings of the app.
The app doesn't really do anything without the home location, but it doesn't prevent me from showing the UI, maybe with a message that app is not configured. Should I let the user progress past the configuration page and pick later or prevent the user from swiping off until the location is picked?
Advantage I can think of letting the user go forward is that it allows him or her to see the UI of the app before investing 3-4 clicks in choosing a location. Disadvantage is that the app doesn't do anything without the config.
If yes, how should I inform the user of the consequences? In my day job, we have a product with this same situation and it shows a popupdialog when the user tries to swipe to inform them. I think it looks terrible because the popup shows up and freezes the page while it is halfway swiped, and it just looks unsmooth. I'd like to avoid that. Maybe a toast?