Dagger: Proper Way To Define Injectable Class That Takes Context In Its Constructor

I want to use dagger (dagger v1 by Square) to create a singleton class whose constructor requires context as an argument. I then want to inject this singleton class into my MainAct

Solution 1:

You need to add the @ForApplication qualifier to your Context parameter in the SingletonClass constructor.

Dagger is now looking for a Context to inject, but only has a @ForApplication Context, which is a mismatch.

@Singleton
public class SingletonClass {

    @Inject
    SingletonClass(@ForApplication Context ctx) {
    }

}

Now you can also get rid of the library = true line in your AndroidModule, which you've probably added because Dagger warned you that @ForApplication Context was unused (Don't ignore these warnings!).

Also, and that might just be a copy-paste error, this SingletonClass should not have an @Module annotation.