really nice helped me a lot for my presentation about Dagger 2 thx :) but i have a question what…
Dia Mamadou

The purpose of this is to pass an injectable object, in this case, MainActivity to Dagger, which then will inject it via Method/Field injection. If you look at MainActivity, it has fields marked with the @Inject annotation. So this means that Dagger 2 will search it graph, and if it can, it will set that field/call an injectable method.