Module per Fragment / Activity in Dagger

Question

I'm wondering if it is better to have a Module per Activity than a Module per Fragment ? In one of my projects, I have an architecture to have a Module per Fragment because I use Activity just to hold and swap Fragments and nothing more. I only create Presenters and Interactors when I need them, ie when Fragment.onCreate() is being called.

But I can see guys are creating Module per Activity in their examples . While the idea to have an independent Module for Activity sounds perfectly reasonable as for me from a modularity perspective, but I still believe creating and keeping all objects ( Presenters , Interactors ) before you actually need them is not a best idea. You can't also release resources when you don't need them, which you could easily do for Module per Fragment when you just release a scoped graph in Fragment.onDestroy() event.

Answer 1

The examples assume you're working with several activities, each with their own clear purpose and scope. There exists a scope A for the application wide dependencies, and scopes B , C and D for each of the Activity dependencies.

You're basically adding an extra layer to the hierarchy: Application-Activity-Fragment. In that case, since you're working with a single Activity, scope A is roughly the scope for the application and activity dependencies, and B , C and D become Fragment scopes.

So yes, it makes sense to create a module for each Fragment.