Why should you use the @Binds annotation instead of the @Provides annotation?

The @Binds annotation is used to tell Dagger which specific implementation of an interface it should provide when the interface itself is requested.

Advantages of using @Binds instead of @Provides in this case:

• Performance: @Binds is more efficient because Dagger generates less code. It simply binds the interface to a specific type without creating a new instance of a module.
• Readability: The code becomes more readable because it is clear which class implements which interface.
• Reducing boilerplate code: When using @Binds, there is no need to write an additional @Provides method that just returns an instance of the implementation.

Example:

Instead of:

@Module
class MyModule {

    @Provides
    fun provideMyInterface(implementation: MyInterfaceImpl): MyInterface {
        return implementation;
    }
}

interface MyInterface {
    // ...
}

class MyInterfaceImpl : MyInterface {
    // ...
}

It is better to use:

@Module
abstract class MyModule { // The module must be abstract

    @Binds
    abstract fun bindMyInterface(implementation: MyInterfaceImpl): MyInterface; // The method must be abstract

}

interface MyInterface {
    // ...
}

class MyInterfaceImpl : MyInterface {
    // ...
}

The @Provides annotation remains necessary for providing objects that are not implementations of interfaces or require more complex instantiation logic (for example, creating objects via builders, providing objects from third-party libraries, providing dependencies that cannot be injected through the constructor).