MVI approach for android

Transcript

1. YET ANOTHER M… TOPIC PAVEL SHCHAHELSKI
2. DISCLAIMER
4. CONTEXT
5. MACHINE OVERVIEW
6. MODEL VIEW INTENT
7. user()
8. intent(user())
9. model(intent(user()))
10. view(model(intent(user())))
11. user(view(model(intent(user()))))
13. UI
14. intent(user())
15. MVI INTENT sealed class BrowseIntent : MviBaseIntent { } interface MviBaseIntent
16. sealed class BrowseIntent : MviBaseIntent { object InitialIntent : BrowseIntent() object RefreshIntent : BrowseIntent() } MVI INTENT
17. MVI INTENT override fun intents(): Observable<BrowseIntent> { return initialIntent() }
18. MVI INTENT private fun initialIntent(): Observable<BrowseIntent.InitialIntent> { return Observable.just(BrowseIntent.InitialIntent) } override fun intents(): Observable<BrowseIntent> { return initialIntent() }
19. MVI INTENT override fun intents(): Observable<BrowseIntent> { return refreshIntent() } private fun initialIntent(): Observable<BrowseIntent.InitialIntent> { return Observable.just(BrowseIntent.InitialIntent) } override fun intents(): Observable<BrowseIntent> { return initialIntent() } private fun refreshIntent(): Observable<BrowseIntent.RefreshIntent> { return RxSwipeRefreshLayout.refreshes(refresh_layout) .map { BrowseIntent.RefreshIntent } }
20. MVI INTENT private fun initialIntent(): Observable<BrowseIntent.InitialIntent> { return Observable.just(BrowseIntent.InitialIntent) } private fun refreshIntent(): Observable<BrowseIntent.RefreshIntent> { return RxSwipeRefreshLayout.refreshes(refresh_layout) .map { BrowseIntent.RefreshIntent } } override fun intents(): Observable<BrowseIntent> { return Observable.merge(initialIntent(), refreshIntent()) }
21. MVI INTENT INITIAL INTENT MERGE INTENTS() REFRESH INTENT
22. MODEL
23. model(intent(user()))
24. MVI MODEL intents //Observable<BrowseIntent> .map(this::actionFromIntent) //Observable<BrowseAction>
25. MVI MODEL private fun actionFromIntent(intent: MviBaseIntent): BrowseAction { return when (intent) { is BrowseIntent.RefreshIntent -> BrowseAction.RefreshAction is BrowseIntent.InitialIntent -> BrowseAction.LoadAction else -> throw UnsupportedOperationException("Oops, that looks like an unknown intent: " + intent) } }
26. MVI MODEL interface MviBaseAction sealed class BrowseAction : MviBaseAction { object LoadAction : BrowseAction() object RefreshAction : BrowseAction() }
27. MVI MODEL MAP TO ACTIONS ACTIONS() INTENTS
28. DATA
29. MVI DATA var actionProcessor: ObservableTransformer<BrowseAction, BrowseResult> = ObservableTransformer { actions -> }
30. MVI DATA var actionProcessor: ObservableTransformer<BrowseAction, BrowseResult> = ObservableTransformer { actions -> actions.publish { shared -> } }
31. MVI DATA var actionProcessor: ObservableTransformer<BrowseAction, BrowseResult> = ObservableTransformer { actions -> actions.publish { shared -> Observable.merge( shared.ofType(LoadAction::class.java).compose(loadProcessor), shared.ofType(RefreshAction::class.java).compose(refreshProcessor) ) } }
32. MVI DATA PUBLISH RESULTS() MERGE ACTIONS ACTION #1 ACTION #2 ACTION #N
33. MVI DATA val loadProcessor: ObservableTransformer<LoadAction, BrowseResult> = ObservableTransformer { actions -> actions.flatMap { getContactList.execute() } }
34. MVI DATA val loadProcessor: ObservableTransformer<LoadAction, BrowseResult> = ObservableTransformer { actions -> actions.flatMap { getContactList.execute() .map { list -> LoadTasksResult.Success(list) } } }
35. MVI DATA val loadProcessor: ObservableTransformer<LoadAction, BrowseResult> = ObservableTransformer { actions -> actions.flatMap { getContactList.execute() .map { list -> LoadTasksResult.Success(list) } .startWith(LoadTasksResult.InFlight) .onErrorReturn(LoadTasksResult::Failure) } }
36. MVI DATA sealed class LoadTasksResult : BrowseResult() { data class Success(val contacts: List<Contact>) : LoadTasksResult() data class Failure(val error: Throwable) : LoadTasksResult() object InFlight : LoadTasksResult() }
37. MVI intents //Observable<BrowseIntent> .map(this::actionFromIntent) //Observable<BrowseAction> .compose(processor.actionProcessor) //Observable<BrowseResult> DATA
38. MVI DATA MAP INTENTS PROCESSOR ACTIONS RESULTS
39. VIEW
40. view(model(intent(user())))
41. MVI interface MviBaseViewState data class BrowseUiViewState : MviBaseViewState VIEW
42. MVI data class BrowseUiViewState(val isLoading: Boolean, val isRefreshing: Boolean, val contacts: List<ContactDisplayObject>, val error: Throwable?) : MviBaseViewState VIEW
43. MVI val reducer: BiFunction<BrowseUiViewState, BrowseResult, BrowseUiViewState> = BiFunction { previousState, result -> } VIEW
44. MVI VIEW intents //Observable<BrowseIntent> .map(this::actionFromIntent) //Observable<BrowseAction> .compose(processor.actionProcessor) //Observable<BrowseResult> .scan(BrowseUiViewState.idle(), reducer) //Observable<BrowseResult>
45. MVI val reducer: BiFunction<BrowseUiViewState, BrowseResult, BrowseUiViewState> = BiFunction { previousState, result -> when (result) { is LoadTasksResult -> { } is RefreshTasksResult -> { } } } VIEW
46. MVI val reducer: BiFunction<BrowseUiViewState, BrowseResult, BrowseUiViewState> = BiFunction { previousState, result -> when (result) { is LoadTasksResult -> { when (result) { is Success -> previousState.copy(isLoading = false, contacts = result.contacts.map { mapper.mapToDisplayObject(it) }) is Failure -> previousState.copy(isLoading = false, error = result.error) is InFlight -> previousState.copy(isLoading = true) } } } } VIEW
47. MVI DATA MAP INTENTS PROCESSOR ACTIONS RESULTS REDUCER UISTATE
48. MVI VIEW intents //Observable<BrowseIntent> .map(this::actionFromIntent) //Observable<BrowseAction> .compose(processor.actionProcessor) //Observable<BrowseResult> .scan(BrowseUiViewState.idle(), reducer) //Observable<BrowseResult> .subscribe { state -> render(state) }
49. MVI VIEW override fun render(state: BrowseUiViewState) { refresh_layout.isRefreshing = state.isRefreshing }
50. MVI VIEW override fun render(state: BrowseUiViewState) { refresh_layout.isRefreshing = state.isRefreshing if (state.isLoading) { progress.visibility = View.VISIBLE list.visibility = View.GONE } }
51. MVI VIEW override fun render(state: BrowseUiViewState) { refresh_layout.isRefreshing = state.isRefreshing if (state.isLoading) { progress.visibility = View.VISIBLE list.visibility = View.GONE } val contacts = state.contacts if (contacts != null) { progress.visibility = View.GONE if (contacts.isNotEmpty()) { browseAdapter.apply { this.contacts = contacts notifyDataSetChanged() } list.visibility = View.VISIBLE } } }
52. USER INTERFACE Intents
53. USER INTERFACE Intents VIEW MODEL Intent Processor To Actions Processor To Result Reducer To State
54. USER INTERFACE Render USER INTERFACE Intents VIEW MODEL Intent Processor To Actions Processor To Result Reducer To State
55. MVI IMPLEMENTATION interface MviBaseView<I : MviBaseIntent, in S : MviBaseViewState> { fun intents(): Observable<I> fun render(state: S) } interface MviBaseViewModel<I : MviBaseIntent, S : MviBaseViewState> { fun processIntents(intents: Observable<I>) fun states(): Observable<S> }
56. MVI IMPLEMENTATION interface MviBaseView<I : MviBaseIntent, in S : MviBaseViewState> { fun intents(): Observable<I> fun render(state: S) } interface MviBaseViewModel<I : MviBaseIntent, S : MviBaseViewState> { fun processIntents(intents: Observable<I>) fun states(): Observable<S> }
57. MVI IMPLEMENTATION interface MviBaseView<I : MviBaseIntent, in S : MviBaseViewState> { fun intents(): Observable<I> fun render(state: S) } interface MviBaseViewModel<I : MviBaseIntent, S : MviBaseViewState> { fun processIntents(intents: Observable<I>) fun states(): Observable<S> }
58. CONFIG CHANGES
60. MVI VIEW MODEL class BrowseContactListViewModel @Inject internal constructor( private val processor: BrowseListProcessor, private val mapper: ContactMapper) : ViewModel(), MviBaseViewModel<BrowseIntent, BrowseUiViewState> { override fun processIntents(intents: Observable<BrowseIntent>) { } override fun states(): Observable<BrowseUiViewState> { } }
61. MVI VIEW MODEL class BrowseContactListViewModel @Inject internal constructor() : ViewModel(), MviBaseViewModel<BrowseIntent, BrowseUiViewState> { private var intentsSubject: PublishSubject<BrowseIntent> = PublishSubject.create() override fun processIntents(intents: Observable<BrowseIntent>) { intents.subscribe(intentsSubject) } override fun states(): Observable<BrowseUiViewState> { } }
62. MVI VIEW MODEL class BrowseContactListViewModel @Inject internal constructor() : ViewModel(), MviBaseViewModel<BrowseIntent, BrowseUiViewState> { private var intentsSubject: PublishSubject<BrowseIntent> = PublishSubject.create() private val statesSubject: BehaviorSubject<BrowseUiViewState> = BehaviorSubject.create() override fun processIntents(intents: Observable<BrowseIntent>) { intents.subscribe(intentsSubject) } override fun states(): Observable<BrowseUiViewState> { return statesSubject } }
63. MVI VIEW MODEL class BrowseContactListViewModel @Inject internal constructor() : ViewModel(), MviBaseViewModel<BrowseIntent, BrowseUiViewState> { private var intentsSubject: PublishSubject<BrowseIntent> = PublishSubject.create() private val statesSubject: BehaviorSubject<BrowseUiViewState> = BehaviorSubject.create() init { intentsSubject .map(this::actionFromIntent) .compose(processor.actionProcessor) .scan<BrowseUiViewState>(BrowseUiViewState.idle(), reducer) .subscribe(statesSubject) } override fun processIntents(intents: Observable<BrowseIntent>) { intents.subscribe(intentsSubject) } override fun states(): Observable<BrowseUiViewState> { return statesSubject } }
64. MVI FRAGMENT override fun onCreate(savedInstanceState: Bundle?) { super.onCreate(savedInstanceState) setContentView(R.layout.a_main) viewModel = ViewModelProviders.of(this, viewModelFactory) .get(BrowseContactListViewModel::class.java) compositeDisposable += viewModel.states().subscribe(this::render) viewModel.processIntents(intents()) } override fun onDestroy() { compositeDisposable.dispose() super.onDestroy() }
65. MVI FRAGMENT override fun onCreate(savedInstanceState: Bundle?) { super.onCreate(savedInstanceState) setContentView(R.layout.a_main) viewModel = ViewModelProviders.of(this, viewModelFactory) .get(BrowseContactListViewModel::class.java) compositeDisposable += viewModel.states().subscribe(this::render) viewModel.processIntents(intents()) } override fun onDestroy() { compositeDisposable.dispose() super.onDestroy() }
66. PShchahelski/MviTestProject
67. PROS & CONS
68. THANK YOU QA?
69. SUMMARY