How do I use AndroidInjection class in custom views or other android classes?

Question

My issue with the Android-specific pattern is, if you use their AndroidInjection class, there is no way to members inject other objects besides Activities

Answer 1

The issue of whether the dagger-android classes like AndroidInjector should support injection inside Views or not has been discussed in the following Github issue:

https://github.com/google/dagger/issues/720

Quoting from one of the library authors:

There is both a philosophical point and logistical/implementation point to be made here.

First, it's not fully clear to us that injecting views is the right thing to do. View objects are meant to draw, and not much else. The controller (in a traditional MVC pattern) is the one which can coordinate and pass around the appropriate data to a view. Injecting a view blurs the lines between fragments and views (perhaps a child fragment is really the appropriate construct instead?)

From the implementation perspective, there is also a problem in that there isn't a canonical way to retrieve the View's parent Fragments (if any), or Activity to retrieve a parent component. There have been hacks suggested to build in that relationship, but so far we haven't seen anything that seems to suggest that we could do this correctly. We could just call View.getContext().getApplicationContext() and inject from there, but skipping the intermediate layers without any option for something in between is inconsistent with the rest of our design, and probably confusing to users even if it works.

This reinforces the opinion expressed in Vasily's answer.

To add further, people often seem to want to inject model-layer dependencies inside their custom views. This is a bad idea as it goes against the software engineering principle of separation of concerns.

The correct solution for associating a view and a model is to write an adapter like the adapters for RecyclerView and ListView. You can inject the model-layer dependency at the Fragment or Presenter level and set the adapter there.