block1.kotlin

class MyFragmentFactory (
    private val requestService: RequestService
) : FragmentFactory() {

    override fun instantiate(classLoader: ClassLoader, className: String): Fragment { ... }

}

// Your Activity
class MainActivity : AppCompatActivity() {

    @Inject
    lateinit var fragmentFactory: MyFragmentFactory

    override fun onCreate(savedInstanceState: Bundle?) {
        supportFragmentManager.fragmentFactory = fragmentFactory
        super.onCreate(savedInstanceState)
        ...
    }
}