Android Programming: The Big Nerd Ranch Guide, 2nd Edition

Application Architecture with Fragments

Designing your app with fragments the right way is supremely important. Many developers, after first learning about fragments, try to use them for every reusable component in their application. This is the wrong way to use fragments.

Fragments are intended to encapsulate major components in a reusable way. A major component in this case would be on the level of an entire screen of your application. If you have a significant number of fragments on screen at once, your code will be littered with fragment transactions and unclear responsibility. A better architectural solution for reuse with smaller components is to extract them into a custom view (a class that subclasses View or one of its subclasses). ...