Communicating between components in Android

So I have an Activity. The Activity hosts a ViewPager with tabs, each tab holding a Fragment in it. The Fragments themselves have a RecyclerView each. I need to communicate changes from the RecyclerView's adapter to the activity.

Currently, I am using the listener pattern and communicating using interface between each of the components. i.e I have an interface between the RecyclerView's adapter and the Fragment holding it. Then an interface from the Fragment to the ViewPager's FragmentStatePagerAdapter which is creating all the Fragments. And 1 more interface between the ViewPager's adapter and the Activity hosting the ViewPager. I feel that there are too many interfaces for all the components because of how they are structured.

Currently I am not facing issues as such but I think the listener pattern is acting like an anti-pattern due to all the nested components. Instead of creating independent components I think the hierarchy will make it difficult for making code changes in future.

Am I doing it correctly or is there a better way to do it? Is this a case where I should use an Event Bus or Observer Pattern (If yes can you point me to some examples where someone overcame a similar problems using it)?

NOTE : If it matters, I need it to maintain a global object in the activity, something like a shopping cart where I can add or remove items and these items are present in RecyclerView's adapter from where I can add it to the cart and also increment or decrement the count for a particular item. The ViewPager and Tabs help segregate these items in various categories.