Subscreens not working in example app

[joserebelo]

Just a head's up that subscreens are not working in the example app:

• It is not possible to navigate to them by clicking the PreferenceScreen
• The preferences are found, but clicking them does not navigate to them

I did manage to fix them on my side following a similar approach to #30. I tried to fix them on the example app as well, but couldn't manage to get the screens to open, and ran out of time. I might revisit this sometime.

[ByteHamster]

Hmm, sounds like Google broke the subscreens in some library update. I remember them working at some point at least.