CODEWITHSUNDEEP
androiddagger-2android-mvp
Jegan Babu
Jegan Babu

Reputation: 1396

(Dagger 2) Provide same instance for different types in MVP

I'm following MVP pattern in my application. I have a view which extends another abstract view class, implements another interface (say A) and also implements View contract (say B) in MVP. I want to have a same instance in dependency graph when I ask for types A and B. How can I achieve that ?

In short:

class MyAbstractView implements MyInterface {

}

class MyView extends MyAbstractView implements MyViewContract {

}

@Module
class MyModule {
    @Provides
    MyInterface provideMyInterface() {
     return new MyView();
    }

    @Provides
    MyViewContract provideMyViewContract() {
       // I cannot call provideMyInterface() and return here
       // but I want to return the same MyView instance
       // ????
   }
}

Note: I dont want to have MyView and persist it in the @Module!!

Upvotes: 0

Views: 683

Answers (1)

Abhishek Jain
Abhishek Jain

Reputation: 3702

You can use constructor injection along with the @Binds annotation in your module to achieve this. Simply add a constructor and annotate it with @Inject in MyView. You can then mark MyView as @Singleton so that the same instance is used everywhere(assuming the component is also scoped with @Singleton).

@Singleton
class MyView extends MyAbstractView implements MyViewContract {
    @Inject
    public MyView() {}
}

@Module
abstract class MyModule {
    @Binds
    abstract MyInterface provideMyInterface(MyView myView);

    @Binds
    abstract MyViewContract provideMyViewContract(MyView myView);
}

Upvotes: 1

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