How do you achieve dependency injection in Android with Dagger?

Dependency injection in Android with Dagger is achieved primarily through the use of annotations such as @Inject, along with the establishment of components and modules. This approach allows for the automatic resolution of dependencies and management of their lifecycle.

When you annotate a field with @Inject, Dagger understands that it needs to provide an instance of that field’s type. Components are responsible for managing the lifecycle of the objects and defining the common interfaces for the modules, which are the building blocks that provide the dependencies. Each module contains methods annotated with @Provides that specify how to create instances of the required types. This setup promotes loose coupling and more manageable code, as dependencies are provided rather than manually instantiated throughout your application.

This method contrasts with the other options that do not align with the principles and mechanisms Dagger employs. For instance, inheritance and interfaces do not inherently facilitate dependency injection in the way Dagger structures it. Static methods for instance creation do not leverage the powerful features of Dagger and can lead to more rigid code. Configuration files are typically not used within Dagger for managing dependencies, making this option less relevant as well.