BaseActivity.kt

abstract class BaseActivity(
    @LayoutRes private val layoutRes: Int? = null
): AppCompatActivity(), InterfaceOne, InterfaceTwo {

    @Inject // now all my children have to use dagger, YAY!
    lateinit var analytics: Analytics

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)

        if (layoutRes != null) {
            setContentView(layoutRes) 
            
            if (foundToolbarWithSomeSpecificId) { 
                init(toolbar)
            }
        }
        // hopefully it's injected by now!
        analytics.sendAnalytics(this, "onCreate")
    }

    override fun onStart() {
        super.onStart()
        analytics.sendAnalytics(this, "onStart")
    }
    
    override fun methodFromInterfaceOne() {
        if (onlyHalfOfTheTimeBasedOnGodKnowsWhat) {
            // do something that should have been in the child class to begin with
        } else {
            // do something that can be removed right now!
        }
    }

    override fun methodFromInterfaceTwo() {
        // I wished it wasn't accessible by child classes ;( 
    }

    open fun onWeirdCallbackOne() {
        // some weird logic that is irrelevant 99% of the time
    }

    abstract fun getSomeWeirdTypeNoOneKnowsWhy(): Int
}