prongbang / mvi-rx

MVI = Rx3 + Relay Android

mvi-rx

Setup

• build.gradle

buildscript {
    repositories {
        maven { url 'https://jitpack.io' }
    }
}

• settings.gradle

dependencyResolutionManagement {
    repositories {
        maven { url 'https://jitpack.io' }
    }
}

• app/build.gradle

implementation 'com.github.prongbang:mvi-rx:1.0.5'

How to use

• MainIntent.kt

import com.prongbang.mvirx.RxIntent

sealed class MainIntent : RxIntent {
	object GetData : MainIntent()
}

• MainSate.kt

import com.prongbang.mvirx.RxState

sealed class MainState : RxState {
	object Idle : MainState()
	data class Result(val data: String) : MainState()
}

• MainEffect.kt

import com.prongbang.mvirx.RxEffect

sealed class MainEffect : RxEffect {
	object Idle : MainEffect()
	data class Error(val data: String) : MainEffect()
}

• GetMessageUseCase.kt

import com.prongbang.mvirx.RxUseCase
import io.reactivex.rxjava3.core.Observable

class GetMessageUseCase : RxUseCase<Unit, String> {
	override fun execute(params: Unit): Observable<String> {
		return Observable.fromCallable {
			"Hello MVI Rx"
		}
	}
}

• MainViewModel.kt

import com.prongbang.mvirx.RxViewModel

class MainViewModel(
		private val getMessageUseCase: GetMessageUseCase
) : RxViewModel<MainIntent, MainState, MainEffect>() {

	override fun process(intent: MainIntent) {
		when (intent) {
			MainIntent.GetData -> processGetData()
		}
	}

	private fun processGetData() {
		getMessageUseCase.execute(Unit)
				.subscribeOn(Schedulers.io())
				.observeOn(AndroidSchedulers.mainThread())
				.subscribeBy(onNext = { result ->
					setState(MainState.Result(result))
				}, onError = {
					setEffect(MainEffect.Error("${it.message}"))
				})
				.addTo(compositeDisposable)
	}
}

• MainActivity.kt

import com.prongbang.mvirx.RxViewRenderer

class MainActivity : AppCompatActivity(), RxViewRenderer<MainState, MainEffect> {

	private val mainViewModel: MainViewModel by viewModels()
    
	override fun onCreate(savedInstanceState: Bundle?) {
		super.onCreate(savedInstanceState)
		setContentView(binding.root)

		mainViewModel.subscribe(::render, ::renderEffect)

		mainViewModel.process(MainIntent.GetData)
	}

	override fun initObserve() {
		mainViewModel.subscribe(::render, ::renderEffect)
	}

	private fun initLoad() {
		mainViewModel.process(MainIntent.GetData)
	}

	override fun render(state: MainState) {
		when (state) {
			is MainState.Result -> {
				findViewById<TextView>(R.id.messageText).text = state.data
			}
		}
	}

	override fun renderEffect(effect: MainEffect) {
		when (effect) {
			is MainEffect.Error -> {
				findViewById<TextView>(R.id.messageText).text = effect.data
			}
		}
	}
}

Unit Test

import io.reactivex.rxjava3.core.Observable
import io.reactivex.rxjava3.observers.TestObserver
import org.junit.Test

class MainViewModelTest : CoreTest() {

	@MockK
	private lateinit var getMessageUseCase: GetMessageUseCase

	private val viewModel by lazy { MainViewModel(getMessageUseCase) }

	@Test
	fun `Should return message when get message success`() {
		// Given
		val result = "Hello MVI Rx"
		val testObserverState = TestObserver.create<MainState>()
		every { getMessageUseCase.execute(Unit) } returns Observable.just(result)

		// When
		viewModel.stateSubscribe(testObserverState)
		viewModel.process(MainIntent.GetData)

		// Then
		testObserverState.assertValues(
				MainState.Result(result)
		)
	}
}