How to create an object using constructor injection?

Question

How would I create an instance of Dog with a component which provides Cat.

public final class Dog {
    private final Ca         


        

Answer 1

To create an object using the Dagger 2 constructor injection feature you need to add a method to a component which provides a Cat class.

@Component(
    dependencies = ApplicationComponent.class,
    modules = CatModule.class)
public interface ActivityComponent {
    void inject(final CatActivity a);
    // objects exposed to sub-components
    Cat cat();
    Dog dog();
}

An instance of Dog can then be retrived by calling [Component].dog().

final ActivityComponent comp = DaggerActivityComponent.builder()
            .applicationComponent(app.getApplicationComponent())
            .build();

final Dog d = comp.dog();