How to instantiate an instance of our dependency graph in Dagger2

Question

I am learning dagger2 dependency injection framework. I loved it how it injects dependency. I read this article https://github.com/codepath/android_guides/wiki/Dependency-Injection-with-Dagger-2 I see there they explained this with the help of two Modules .

AppModule & NetModule are the two Modules . Both has constructors, so they instantiate an instance of our dependency graph like this

 mNetComponent = DaggerNetComponent.builder()
                // list of modules that are part of this component need to be created here too
                .appModule(new AppModule(this)) // This also corresponds to the name of your module: %component_name%Module
                .netModule(new NetModule("https://api.github.com"))
                .build();

Suppose I have one more Modules which do not have a constructor then how would I initialize it, as other 2 modules need values in the constructor ?

Thanks

Answer 1

If your third module doesn't need a constructor Dagger2 will automatically add it to component if you list it in @Component 's modules like this:

 @Component(modules = {
     AppModule.class,
     NetModule.class,
     ThirdModule.class // module without constructor
 })
 public interface NetComponent{
     // ...
 }

Answer 2

Let's say your third module is TestModule:

you can simply do this:

 mNetComponent = DaggerNetComponent.builder()        
                .appModule(new AppModule(this)) 
                .netModule(new NetModule("https://api.github.com"))
                .testModule(new TestModule())
                .build();

Note: here .testModule will give you deprecated warning which means that you don't even have to define modules that have no constructors. They are implicitly added to the graph.