SimpleActivity.kt

class SimpleActivity : AppCompatActivity() {

    private var store = Store(0)
    private val subscriptions = CompositeSubscription()

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_counter)
        setTitle(R.string.simple_activity_name)

        subscriptions.add(states(store).observeOn(mainThread())
                .subscribe({ it -> counterText.text = it.toString() }, this::onError))

        subscriptions.add(RxView.clicks(incrementButton)
                .flatMap { IncrementCounterCommand().actions() as Observable<Action<Int>> }
                .subscribe(store::dispatch, this::onError))

        subscriptions.add(RxView.clicks(decrementButton)
                .flatMap { DecrementCounterCommand().actions() as Observable<Action<Int>> }
                .subscribe(store::dispatch, this::onError))
    }

    override fun onDestroy() {
        subscriptions.unsubscribe();
        super.onDestroy()
    }

    private fun onError(throwable: Throwable) = Unit
}