How to inject nested classes using Dagger2

Question

I am working on Android application. I am using Dagger2 for dependency injection. I am able to use this library but I don't know how to inject nested classes.

        public class Parent {

            @Inject
            public Parent()
           {}

            public String getParent() {

                return "fifth";
            }

            class ParentSubClass{

             @Inject
             public ParentSubClass(){
             }

                public String getParentSubClass(){
                    return "subfifth";
                }

            }
    }


  class SomeTest{

  @Inject
  Parent.ParentSubClass subclass;


}

I know injecting parent class but how to create object for parentsubclass

Answer 1

@Inject constructors are not supported on inner classes as Dagger tells us in the logcat:

error: @Inject constructors are invalid on inner classes public ParentSubClass()

If you'd like to provide your inner class, you should provide it using a @Provides method:

@Provides
internal fun provideSubclass() : ParentSubClass {
    return Parent().ParentSubClass()
}

Answer 2

该示例中的嵌套类可以访问其所有父级属性，因此您可以在父级中注入所需的所有依赖项，然后在子类中使用它们。