Using ViewModel and LiveData

I’m made a project for school very similar to the Criminal Activity. I’m adding the MasterDetail feature and using the techniques in this chapter.

Question do I still need a callback interface to talk between the fragments if I’m using ViewModel and LiveData?

I’m going to experiment a bit more but was curious on this. My detail fragment already communicates with my main fragment without implementing the callback interface on the detail fragment.

Thank you.

Okay tried without using the interface but got a null pointer exception I suspect is because I’m not assigning the Main Activity’s Context on onAttached. So it seems I should still use the interface just to connect the hosting activity with main fragment?