Airbnb MvRx Early Look

SimpleDemo.kt

data class SimpleDemoState(val listing: Async<Listing> = Uninitialized)

class SimpleDemoViewModel(override val initialState: SimpleDemoState) : MvRxViewModel<SimpleDemoState>() {
    init {
        fetchListing()
    }

    private fun fetchListing() {
        // This automatically fires off a request and maps its response to Async<Listing>
        // which is a sealed class and can be: Unitialized, Loading, Success, and Fail.
        // No need for separate success and failure handlers!
        // This request is also lifecycle-aware. It will survive configuration changes and
        // will never be delivered after onStop.
        ListingRequest.forListingId(12345L).execute { copy(listing = it) }
    }
}

class SimpleDemoFragment : MvRxFragment() {
    // This will automatically subscribe to the ViewModel state and rebuild the epoxy models
    // any time anything changes. Similar to how React's render method runs for every change of
    // props or state.
    private val viewModel by fragmentViewModel(SimpleDemoViewModel::class)

    override fun EpoxyController.buildModels() {
        val (state) = withState(viewModel)
        if (state.listing is Loading) {
            loader()
            return
        }
        // These Epoxy models are not the views themself so calling buildModels is cheap. RecyclerView
        // diffing will be automaticaly done and only the models that changed will re-render.
        documentMarquee {
            title(state.listing().name)
        }
        // Put the rest of your Epoxy models here...
    }

    override fun EpoxyController.buildFooter() = fixedActionFooter {
        val (state) = withState(viewModel)
        buttonLoading(state is Loading)
        buttonText(state.listing().price)
        buttonOnClickListener { _ -> }
    }
}

Hopefully, we can see more soon. It would great to involve the Open Source community, so we can see if it's something we want to contribute to.

@cesards

https://github.com/airbnb/MvRx/wiki