Separate your concerns with clean MVI

It’s become a norm to architect our code bases with either of the most popular architecture patterns. It’s even become a thing to have a hard time making decision on which pattern to pick given a number of options are available out there nowadays.

MVI is one of the latest to join the MV* gang in android Community. It best solves the state management problem by making the data/business logic drives the app’s state and leveraging data immutability. We’ll dive into the nitty-gritty of managing states the MVI way.

Views in android are already complex in its nature. MVI makes the view as dump and passive as possible to the point where the only concern left for a view is rendering data and firing events. Nothing more.

We’ll also go through a technique for building complex UI using a single recycler view with the help of Epoxy library which works very well with MVI. And of course, some caveats of using this library along with MVI.

Not necessarily a requirement but MVI shines the brightest when used together with reactive framework like Rxjava. Here’s the thing, simply using Rxjava doesn’t make your app reactive. You might have heard or seen something similar to this a couple of times, I’m using Rxjava/LiveData but still have to refresh the calls to get the latest updates when come back from another screen ¯_(ツ)_/¯. We’ll go through the process of making our app fully reactive. No more refresh.

Needless to advocate much for the benefits clean architecture has to offer. It’s here to stay. It ensures that components with different purposes will sit at their respective places thus enable us to concern about only one thing at a place. It makes sure the more important business logic doesn’t depend on the less important implementation details. The list goes on and on. On the other hand, MVI is just a view layer pattern so it still needs something which is capable of all these cool things. Then comes the clean MVI.

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1. HELLO, WORLD! WE ARE CODIGO.
2. Speakers
3. MVI + CLEAN ARCHITECTURE
4. History Codigo Founded Codigo 2010 2012 Creative Director 2019 Best Agency Award Vietnam Dev Team Grow SG Dev Team Myanmar Dev Team 2015 2017 2017 2014 188 Apps
5. NEW GOALS & THE JOURNEY
6. Codigo
7. Codigo Better Apps Best Practices Good Coding Standards Proper Development Workflow Proper Framework
8. What’s before CLEAN MVI
9. No Architecture
10. 2900+ Journey – No Architecture Codigo
11. 29,000+ Journey – No Architecture Codigo
12. 2900+ Journey – No Architecture Codigo ctrl + F
13. 2900++ Journey – No Architecture Codigo
14. 2900+++ Journey – No Architecture Codigo
15. Codigo MVP model-view-presenter
16. No Arch MVP View Presenter Model Codigo
17. View Presenter Model Codigo
18. Activity / Fragment Presenter REST API / Database Codigo
19. Codigo But…
20. Accept input Get Data Presenter Task 1: Activity / Fragment Presenter REST API / Database Codigo
21. Codigo Codigo Render Output Prepare Presenter Task 2: Activity / Fragment Presenter REST API / Database
22. Codigo Codigo MVP Problems Faced: - Presenter can still be messy
23. MVP Problems Faced: - Presenter can still be messy - Different states in view layer and business logic layer Codigo
24. getList() getList() View To-Do List Activity / Fragment Presenter REST API / Database Codigo
25. Presenter REST API / Database Activity / Fragment Codigo Codigo List<ToDo> List<ToDo> View To-Do List
26. Presenter REST API / Database Activity / Fragment Codigo Codigo Different States Edit To-Do List
27. Presenter REST API / Database Activity / Fragment getList() getList() View To-Do List Codigo
28. Presenter REST API / Database Activity / Fragment List<ToDo> List<ToDo> View To-Do List Codigo
29. MVP Problems Faced: - Presenter can still be messy - Different states in view layer and business logic layer - Overlapping states Codigo
30. Codigo
31. Codigo
32. Oops! Something went wrong Error message OK Overlapping states Codigo
33. Codigo Unexpected states
34. MVI model-view-intent Codigo
35. Team’s Journey Codigo
36. WHAT CHANGED? Codigo
37. What has changed? MVI Ease of Maintenance Clean Style Security App Performance Best practices ProGuard Architecture Quicker Bug fix Features CI/ CD Code Quality Encryption Sensitive Data Codigo
38. Separate your concerns with CLEAN MVI Codigo
39. Well, what is concern actually? • User interface • Presentation • Business Logic • Network Request • Database Codigo
40. Clean Architecture cr: image from clean coder Codigo
41. • Independent of framework, UI, Database • Testable in isolation Use Case Codigo
42. SCREAMING ARCHITECTURE Codigo
43. Screaming Architecture cr: image from achildsplaceatmercy Codigo
44. Screaming Architecture cr: image from Litchfield public library Codigo
45. Screaming Architecture “A good architecture should scream the use case of the system.” Codigo
46. CLEAN ARCHITECTURE IN ANDROID Codigo
47. Codigo Clean Architecture Presenter Use Case Output Port Use Case Use Use Case Input Port Controller Flow of control <Interface> <Interface>
48. Codigo Clean Architecture Presenter Use Case Output Port Use Case Use Use Case Input Port Flow of control <Interface> <Interface>
49. Codigo Clean Architecture Presenter Use Case Output Port Use Case Flow of control <Interface>
50. Codigo Clean Architecture Presenter Use Case Flow of control
51. Layered Architecture Codigo
52. Layered Architecture Codigo
53. Codigo Layered Architecture View Layer
54. Codigo Layered Architecture View Layer Domain Layer
55. View Layer Domain Layer Codigo Layered Architecture Data Layer
56. Codigo Dependency Rule
57. View Layer Domain Layer Data Layer Dependency Rule Codigo
58. Dependency Direction Dependency Direction
59. Dependency Direction Dependency Direction Dependency Direction
60. Codigo Dependency Inversion
61. Domain Layer Data Layer Codigo Dependency Inversion Use Cases
62. Domain Layer Use Cases Data Layer Repository <I> Codigo Dependency Inversion
63. Domain Layer Data Layer Repository RepositoryImpl Codigo Dependency Inversion Use Cases <I>
64. Domain Layer Data Layer Repository RepositoryImpl File/ Pref Network DB Codigo Dependency Inversion <I> Use Cases
65. MVI Codigo
66. Model - View - Intent Codigo
67. Model View Intent Codigo MVI
68. How we work with model in MVP? Codigo
69. fun fetchHotels() { } Codigo
70. fun fetchHotels() { getView().showLoading() } Codigo
71. fun fetchHotels() { getView().showLoading() fetchHotelsFromServer(object: Callback { override fun onSuccess(hotels: List<Hotel>) { } override fun onError(error: Throwable) { } }) } Codigo
72. fun fetchHotels() { getView().showLoading() fetchHotelsFromServer(object: Callback { override fun onSuccess(hotels: List<Hotel>) { getView().stopLoading() getView().renderHotels(hotels) } override fun onError(error: Throwable) { } }) } Codigo
73. fun fetchHotels() { getView().showLoading() fetchHotelsFromServer(object: Callback { override fun onSuccess(hotels: List<Hotel>) { getView().stopLoading() getView().renderHotels(hotels) } override fun onError(error: Throwable) { getView().stopLoading() getView().showError(error) } }) } Codigo
74. fun fetchHotels() { getView().showLoading() fetchHotelsFromServer(object: Callback { override fun onSuccess(hotels: List<Hotel>) { getView().stopLoading() getView().renderHotels(hotels) } override fun onError(error: Throwable) { getView().stopLoading() getView().showError(error) } }) } Codigo
75. fun fetchHotels() { getView().showLoading() fetchHotelsFromServer(object: Callback { override fun onSuccess(hotels: List<Hotel>) { getView().stopLoading() getView().renderHotels(hotels) } override fun onError(error: Throwable) { getView().stopLoading() getView().showError(error) } }) } Codigo
76. fun fetchHotels() { getView().showLoading() fetchHotelsFromServer(object: Callback { override fun onSuccess(hotels: List<Hotel>) { getView().stopLoading() getView().renderHotels(hotels) } override fun onError(error: Throwable) { getView().stopLoading() getView().showError(error) } }) } Codigo
77. How we work with model in MVVM? Codigo
78. fun fetchHotels() { loading.onNext(true) } Codigo
79. fun fetchHotels() { loading.onNext(true) fetchHotelsFromServer(object: Callback { override fun onSuccess(hotels: List<Hotel>) { loading.onNext(false) hotelList.onNext(hotels) } override fun onError(error: Throwable) { } }) } Codigo
80. fun fetchHotels() { loading.onNext(true) fetchHotelsFromServer(object: Callback { override fun onSuccess(hotels: List<Hotel>) { loading.onNext(false) hotelList.onNext(hotels) } override fun onError(error: Throwable) { loading.onNext(false) error.onNext(error) } }) } Codigo
81. Codigo Model in MVI
82. val hotels: List<Hotel>, Codigo
83. val hotels: List<Hotel>, val loading: Boolean, Codigo
84. val hotels: List<Hotel>, val loading: Boolean, val error: Throwable? Codigo
85. data class HotelViewState( val hotels: List<Hotel>, val loading: Boolean, val error: Throwable? ) Codigo
86. data class HotelViewState( val hotels: List<Hotel> = emptyList(), val loading: Boolean = false, val error: Throwable? = null ) Codigo
87. fun fetchHotels() { getView().render(HotelViewState(loading = true) } Codigo
88. fun fetchHotels() { getView().render(HotelViewState(loading = true) fetchHotelsFromServer(object: Callback { override fun onSuccess(hotels: List<Hotel>) { getView().render(HotelViewState(hotels = hotels) } override fun onError(error: Throwable) { } }) } Codigo
89. fun fetchHotels() { getView().render(HotelViewState(loading = true) fetchHotelsFromServer(object: Callback { override fun onSuccess(hotels: List<Hotel>) { getView().render(HotelViewState(hotels = hotels) } override fun onError(error: Throwable) { getView().render(HotelViewState(error = error) } }) } Codigo
90. Codigo Model should reflect the state
91. Then what? Basically, presenter still manipulates the state. Codigo
92. class HotelInteractor { fun fetchHotels() { } } Codigo
93. class HotelInteractor { fun fetchHotels() : Observable<HotelViewState> { } } Codigo
94. class HotelInteractor constructor ( private val hotelRepo: HotelRepository ) { fun fetchHotels() : Observable<HotelViewState> { } } Codigo
95. class HotelInteractor constructor ( private val hotelRepo: HotelRepository ) { fun fetchHotels() : Observable<HotelViewState> { return hotelRepo.fetchHotels() } } Codigo
96. class HotelInteractor constructor ( private val hotelRepo: HotelRepository ) { fun fetchHotels() : Observable<HotelViewState> { return hotelRepo.fetchHotels() .map { HotelViewState(hotels = it) } } } Codigo
97. class HotelInteractor constructor ( private val hotelRepo: HotelRepository ) { fun fetchHotels() : Observable<HotelViewState> { return hotelRepo.fetchHotels() .map { HotelViewState(hotels = it) } .startWith(HotelViewState(loading = true)) } } Codigo
98. class HotelInteractor constructor ( private val hotelRepo: HotelRepository ) { fun fetchHotels() : Observable<HotelViewState> { return hotelRepo.fetchHotels() .map { HotelViewState(hotels = it) } .startWith(HotelViewState(loading = true)) .onErrorReturn { HotelViewState(error = it) } } } Codigo
99. class HotelInteractor constructor ( private val hotelRepo: HotelRepository, private val backgroundThread: BackgroundThread ) { fun fetchHotels() : Observable<HotelViewState> { return hotelRepo.fetchHotels() .map { HotelViewState(hotels = it) } .startWith(HotelViewState(loading = true)) .onErrorReturn { HotelViewState(error = it) } } } Codigo
100. class HotelInteractor constructor ( private val hotelRepo: HotelRepository, private val backgroundThread: BackgroundThread, private val uiThread: UiThread ) { fun fetchHotels() : Observable<HotelViewState> { return hotelRepo.fetchHotels() .map { HotelViewState(hotels = it) } .startWith(HotelViewState(loading = true)) .onErrorReturn { HotelViewState(error = it) } } } Codigo
101. class HotelInteractor constructor ( private val hotelRepo: HotelRepository, private val backgroundThread: BackgroundThread, private val uiThread: UiThread ) { fun fetchHotels() : Observable<HotelViewState> { return hotelRepo.fetchHotels() .map { HotelViewState(hotels = it) } .startWith(HotelViewState(loading = true)) .onErrorReturn { HotelViewState(error = it) } .subscribeOn(backgroundThread.getScheduler()) } } Codigo
102. class HotelInteractor constructor ( private val hotelRepo: HotelRepository, private val backgroundThread: BackgroundThread, private val uiThread: UiThread ) { fun fetchHotels() : Observable<HotelViewState> { return hotelRepo.fetchHotels() .map { HotelViewState(hotels = it) } .startWith(HotelViewState(loading = true)) .onErrorReturn { HotelViewState(error = it) } .subscribeOn(backgroundThread.getScheduler()) .observeOn(uiThread.getScheduler()) } } Codigo
103. class HotelInteractor constructor ( private val hotelRepo: HotelRepository, private val backgroundThread: BackgroundThread, private val uiThread: UiThread ) { fun fetchHotels() : Observable<HotelViewState> { return hotelRepo.fetchHotels() .map { HotelViewState(hotels = it)} .startWith(HotelViewState(loading = true)) .onErrorReturn { HotelViewState(error = it)} .subscribeOn(backgroundThread.getScheduler()) .observeOn(uiThread.getScheduler()) } } Codigo
104. Model-View-Intent Codigo
105. Codigo interface HotelView { } Codigo
106. interface HotelView { fun fetchHotelsIntent() : Observable<Any> } Codigo
107. interface HotelView { fun fetchHotelsIntent() : Observable<Any> fun render(viewState: HotelViewState) } Codigo
108. class HotelActivity: HomeView { fun fetchHotelsIntent() : Observable<Any> { } fun render(viewState: HotelViewState) { } } Codigo
109. class HotelActivity: HomeView { private val fetchHotelsSubject = PublishSubject.create<Any>() fun fetchHotelsIntent() : Observable<Any> { } fun render(viewState: HotelViewState) { } } Codigo
110. class HotelActivity: HomeView { private val fetchHotelsSubject = PublishSubject.create<Any>() fun onResume() { super.onResume() fetchHotelsSubject.onNext(Any()) } fun fetchHotelsIntent() : Observable<Any> { } fun render(viewState: HotelViewState) { } } Codigo
111. class HotelActivity: HomeView { private val fetchHotelsSubject = PublishSubject.create<Any>() fun onResume() { super.onResume() fetchHotelsSubject.onNext(Any()) } fun fetchHotelsIntent() : Observable<Any> { return fetchHotelsSubject } fun render(viewState: HotelViewState) { } } Codigo
112. class HotelActivity: HomeView { private val fetchHotelsSubject = PublishSubject.create<Any>() fun onResume() { super.onResume() fetchHotelsSubject.onNext(Any()) } fun fetchHotelsIntent() : Observable<Any> { return fetchHotelsSubject } fun render(viewState: HotelViewState) { progressBar.visibility = if (viewState.loading) View.VISIBLE else View.GONE } } Codigo
113. class HotelActivity: HomeView { private val fetchHotelsSubject = PublishSubject.create<Any>() fun onResume() { super.onResume() fetchHotelsSubject.onNext(Any()) } fun fetchHotelsIntent() : Observable<Any> { return fetchHotelsSubject } fun render(viewState: HotelViewState) { progressBar.visibility = if (viewState.loading) View.VISIBLE else View.GONE tvError.visibility = if (viewState.error != null) View.VISIBLE else View.GONE tvError.text = viewState.error?.localizedMessage } } Codigo
114. class HotelActivity: HomeView { private val fetchHotelsSubject = PublishSubject.create<Any>() fun onResume() { super.onResume() fetchHotelsSubject.onNext(Any()) } fun fetchHotelsIntent() : Observable<Any> { return fetchHotelsSubject } fun render(viewState: HotelViewState) { progressBar.visibility = if (viewState.loading) View.VISIBLE else View.GONE tvError.visibility = if (viewState.error != null) View.VISIBLE else View.GONE tvError.text = viewState.error?.localizedMessage adapter.setHotelList(viewState.hotels) } } Codigo
115. class HotelActivity: HomeView { private val fetchHotelsSubject = PublishSubject.create<Any>() fun onResume() { super.onResume() fetchHotelsSubject.onNext(Any()) } fun fetchHotelsIntent() : Observable<Any> { return fetchHotelsSubject } fun render(viewState: HotelViewState) { progressBar.visibility = if (viewState.loading) View.VISIBLE else View.GONE tvError.visibility = if (viewState.error != null) View.VISIBLE else View.GONE tvError.text = viewState.error?.localizedMessage adapter.setHotelList(viewState.hotels) } } Codigo
116. Codigo Connecting the dots with Mosby
117. Codigo
118. // Internally create PublishSubject that subscribes to intents from the view fun intent(binder) : Observable<I> Codigo
119. // Internally create PublishSubject that subscribes to intents from the view fun intent(binder) : Observable<I> // Internally create a BehaviorSubject that subscribes to viewStates emitted by the // business logic fun subscribeToViewState(viewStateObservable, consumer) Codigo
120. class HotelPresenter : MviBasePresenter<..> { } Codigo
121. class HotelPresenter : MviBasePresenter<..> { fun bindIntents() { } fun unbindIntents() { } } Codigo
122. class HotelPresenter constructor ( private val interactor: HotelInteractor ) : MviBasePresenter<..> { fun bindIntents() { } } Codigo
123. class HotelPresenter constructor ( private val interactor: HotelInteractor ) : MviBasePresenter<..> { fun bindIntents() { val fetchHotelsIntent = intent { hotelView -> hotelView.fetchHotelsIntent() } } } Codigo
124. class HotelPresenter constructor ( private val interactor: HotelInteractor ) : MviBasePresenter<..> { fun bindIntents() { val fetchHotelsIntent: Observable<Any> = intent { hotelView -> hotelView.fetchHotelsIntent() } } } Codigo
125. class HotelPresenter constructor ( private val interactor: HotelInteractor ) : MviBasePresenter<..> { fun bindIntents() { val fetchHotelsIntent: Observable<Any> = intent { hotelView -> hotelView.fetchHotelsIntent() } val fetchHotelsState = fetchHotelsIntent .switchMap { interactor.fetchHotels() } } } Codigo
126. class HotelPresenter constructor ( private val interactor: HotelInteractor ) : MviBasePresenter<..> { fun bindIntents() { val fetchHotelsIntent: Observable<Any> = intent { hotelView -> hotelView.fetchHotelsIntent() } val fetchHotelsState: Observable<HotelViewState> = fetchHotelsIntent .switchMap { interactor.fetchHotels() } } } Codigo
127. class HotelPresenter constructor ( private val interactor: HotelInteractor ) : MviBasePresenter<..> { fun bindIntents() { val fetchHotelsIntent: Observable<Any> = intent { hotelView -> hotelView.fetchHotelsIntent() } val fetchHotelsState: Observable<HotelViewState> = fetchHotelsIntent .switchMap { interactor.fetchHotels() } subscribeViewState() } fun unbindIntents() { } } Codigo
128. class HotelPresenter constructor ( private val interactor: HotelInteractor ) : MviBasePresenter<..> { fun bindIntents() { val fetchHotelsIntent: Observable<Any> = intent { hotelView -> hotelView.fetchHotelsIntent() } val fetchHotelsState: Observable<HotelViewState> = fetchHotelsIntent .switchMap { interactor.fetchHotels() } subscribeViewState(fetchHotelsState) } fun unbindIntents() { } } Codigo
129. class HotelPresenter constructor ( private val interactor: HotelInteractor ) : MviBasePresenter<..> { fun bindIntents() { val fetchHotelsIntent: Observable<Any> = intent { hotelView -> hotelView.fetchHotelsIntent() } val fetchHotelsState: Observable<HotelViewState> = fetchHotelsIntent .switchMap { interactor.fetchHotels() } subscribeViewState(fetchHotelsState, { hotelView, viewState -> hotelView.render(viewState) }) } fun unbindIntents() { } } Codigo
130. class HotelPresenter constructor ( private val interactor: HotelInteractor ) : MviBasePresenter<..> { fun bindIntents() { val fetchHotelsIntent: Observable<Any> = intent { hotelView -> hotelView.fetchHotelsIntent() } val fetchHotelsState: Observable<HotelViewState> = fetchHotelsIntent .switchMap { interactor.fetchHotels() } subscribeViewState(fetchHotelsState, { hotelView, viewState -> hotelView.render(viewState) }) } fun unbindIntents() { } } Codigo
131. class HotelPresenter constructor ( private val interactor: HotelInteractor ) : MviBasePresenter<..> { fun bindIntents() { val fetchHotelsState: Observable<HotelViewState> = intent { hotelView -> hotelView.fetchHotelsIntent() } .switchMap { interactor.fetchHotels() } subscribeViewState(fetchHotelsState, { hotelView, viewState -> hotelView.render(viewState) }) } fun unbindIntents() { } } Codigo
132. class HotelPresenter constructor ( private val interactor: HotelInteractor ) : MviBasePresenter<..> { fun bindIntents() { val fetchHotelsState = intent { it.fetchHotelsIntent() } .switchMap { interactor.fetchHotels() } subscribeViewState(fetchHotelsState, { hotelView, viewState -> hotelView.render(viewState) }) } fun unbindIntents() { } } Codigo
133. interface HotelView { fun fetchHotelsIntent() : Observable<Any> fun fetchAirportsIntent() : Observable<Any> fun render(viewState: HotelViewState) } Codigo
134. data class HotelViewState( val hotels: List<Hotel> = emptyList(), val loading: Boolean = false, val error: Throwable? = null ) Codigo
135. data class HotelViewState( val hotels: List<Hotel> = emptyList(), val loading: Boolean = false, val error: Throwable? = null, val airports: List<Airport> = emptyList(), val loadingAirport: Boolean = false, val loadAirportError: Throwable? = null ) Codigo
136. data class HotelViewState( val hotels: List<Hotel> = emptyList(), val loadingHotels: Boolean = false, val loadHotelError: Throwable? = null, val airports: List<Airport> = emptyList(), val loadingAirports: Boolean = false, val loadAirportsError: Throwable? = null ) Codigo
137. class HotelPresenter constructor ( private val interactor: HotelInteractor ) : MviBasePresenter<..> { fun bindIntents() { val fetchHotelsState = intent { it.fetchHotelsIntent() } .switchMap { interactor.fetchHotels() } val fetchAirportsState = intent { it.fetchAirportsIntent() } .switchMap { interactor.fetchAirports() } subscribeViewState(fetchHotelsState, { hotelView, viewState -> hotelView.render(viewState) }) } } Codigo
138. class HotelInteractor constructor (...) { fun fetchHotels() : Observable<HotelViewState> { ... } fun fetchAirports() : Observable<HotelViewState> { } } Codigo
139. class HotelInteractor constructor (...) { fun fetchHotels() : Observable<HotelViewState> { ... } fun fetchAirports() : Observable<HotelViewState> { return hotelRepo.fetchAirports() .map { HotelViewState(airports = it)} } } Codigo
140. class HotelInteractor constructor (...) { fun fetchHotels() : Observable<HotelViewState> { ... } fun fetchAirports() : Observable<HotelViewState> { return hotelRepo.fetchAirports() .map { HotelViewState(airports = it)} .startWith(HotelViewState(loadingAirport = true)) } } Codigo
141. class HotelInteractor constructor (...) { fun fetchHotels() : Observable<HotelViewState> { ... } fun fetchAirports() : Observable<HotelViewState> { return hotelRepo.fetchAirports() .map { HotelViewState(airports = it)} .startWith(HotelViewState(loadingAirport = true)) .onErrorReturn { HotelViewState(loadAirportError = it)} } } Codigo
142. class HotelInteractor constructor (...) { fun fetchHotels() : Observable<HotelViewState> { ... } fun fetchAirports() : Observable<HotelViewState> { return hotelRepo.fetchAirports() .map { HotelViewState(airports = it)} .startWith(HotelViewState(loadingAirport = true)) .onErrorReturn { HotelViewState(loadAirportError = it)} .subscribeOn(backgroundThread.getScheduler()) .observeOn(uiThread.getScheduler()) } } Codigo
143. Codigo
144. class HotelInteractor constructor (...) { fun fetchHotels() : Observable<HotelViewState> { ... } fun fetchAirports() : Observable<HotelViewState> { return hotelRepo.fetchAirports() .map { HotelViewState(airports = it)} .startWith(HotelViewState(loadingAirport = true)) .onErrorReturn { HotelViewState(loadAirportError = it)} .subscribeOn(backgroundThread.getScheduler()) .observeOn(uiThread.getScheduler()) } } Codigo
145. Codigo State Reducer
146. Codigo
147. Codigo
148. Codigo
149. Old state Partial state
150. Old state Partial state New state
151. Old state
152. Old state Partial state
153. Old state Partial state New state
154. Old state
155. Old state Partial state
156. Old state Partial state New state
157. seal class HotelPartialState { abstract fun reduce(oldState: HotelViewState) : HotelViewState } Codigo
158. seal class HotelPartialState { abstract fun reduce(oldState: HotelViewState) : HotelViewState object LoadingHotels : HotelPartialState() { override fun reduce(oldState: HotelViewState) : HotelViewState { } } } Codigo
159. seal class HotelPartialState { abstract fun reduce(oldState: HotelViewState) : HotelViewState object LoadingHotels : HotelPartialState() { override fun reduce(oldState: HotelViewState) : HotelViewState { oldState.copy( loadingHotels = true, loadHotelsError = null ) } } } Codigo
160. seal class HotelPartialState { abstract fun reduce(oldState: HotelViewState) : HotelViewState data class HotelsResult( val hotels: List<Hotel> ) : HotelPartialState() { override fun reduce(oldState: HotelViewState) : HotelViewState { } } } Codigo
161. seal class HotelPartialState { abstract fun reduce(oldState: HotelViewState) : HotelViewState data class HotelsResult( val hotels: List<Hotel> ) : HotelPartialState() { override fun reduce(oldState: HotelViewState) : HotelViewState { oldState.copy( hotels = hotels, loadingHotels = false, loadHotelsError = null ) } } } Codigo
162. seal class HotelPartialState { abstract fun reduce(oldState: HotelViewState) : HotelViewState data class AirportsResult( val airports: List<Airport> ) : HotelPartialState() { override fun reduce(oldState: HotelViewState) : HotelViewState { } } } Codigo
163. seal class HotelPartialState { abstract fun reduce(oldState: HotelViewState) : HotelViewState data class AirportsResult( val airports: List<Airport> ) : HotelPartialState() { override fun reduce(oldState: HotelViewState) : HotelViewState { oldState.copy( airports = airports, loadingAirports = false, loadAirportsError = null ) } } } Codigo
164. class HotelInteractor constructor (...) { fun fetchHotels() : Observable<HotelPartialState> { ... } fun fetchAirports() : Observable<HotelPartialState> { ... } } Codigo
165. class HotelInteractor constructor (...) { fun fetchHotels() : Observable<HotelPartialState> { return hotelRepo.fetchHotels() .map { HotelPartialState.HotelsResult(it) } } fun fetchAirports() : Observable<HotelPartialState> { ... } } Codigo
166. class HotelInteractor constructor (...) { fun fetchHotels() : Observable<HotelPartialState> { return hotelRepo.fetchHotels() .map { HotelPartialState.HotelsResult(it) } .startWith(HotelPartialState.LoadingHotels) } fun fetchAirports() : Observable<HotelPartialState> { ... } } Codigo
167. class HotelInteractor constructor (...) { fun fetchHotels() : Observable<HotelPartialState> { return hotelRepo.fetchHotels() .map { HotelPartialState.HotelsResult(it) } .startWith(HotelPartialState.LoadingHotels) .onErrorReturn { HotelPartialState.LoadHotelsError(it) } } fun fetchAirports() : Observable<HotelPartialState> { ... } } Codigo
168. class HotelInteractor constructor (...) { fun fetchHotels() : Observable<HotelPartialState> { return hotelRepo.fetchHotels() .map { HotelPartialState.HotelsResult(it) } .startWith(HotelPartialState.LoadingHotels) .onErrorReturn { HotelPartialState.LoadHotelsError(it) } .subscribeOn(backgroundThread.getScheduler()) .observeOn(uiThread.getScheduler()) } fun fetchAirports() : Observable<HotelPartialState> { ... } } Codigo
169. class HotelPresenter constructor ( private val interactor: HotelInteractor ) : MviBasePresenter<..> { fun bindIntents() { val fetchHotelsState = intent { it.fetchHotelsIntent() } .switchMap { interactor.fetchHotels() } val fetchAirportsState = intent { it.fetchAirportsIntent() } .switchMap { interactor.fetchAirports() } } } Codigo
170. class HotelPresenter constructor ( ...) : MviBasePresenter<..> { fun bindIntents() { val fetchHotelsState = ... val fetchAirportsState = ... val states: Observable<HotelPartialState> = Observable.merge( fetchHotelsState, fetchAirportsState ) } } Codigo
171. class HotelPresenter constructor ( ...) : MviBasePresenter<..> { fun bindIntents() { val fetchHotelsState = ... val fetchAirportsState = ... val states: Observable<HotelPartialState> = Observable.merge( fetchHotelsState, fetchAirportsState ) val reducedStates : Observable<HotelViewState> = states.scan(HotelViewState(), { oldState, partialState -> partialState.reduce(oldState) } } } Codigo
172. class HotelPresenter constructor ( ...) : MviBasePresenter<..> { fun bindIntents() { val fetchHotelsState = ... val fetchAirportsState = ... val states: Observable<HotelPartialState> = Observable.merge( fetchHotelsState, fetchAirportsState ) val reducedStates : Observable<HotelViewState> = states.scan(HotelViewState(), { oldState, partialState -> partialState.reduce(oldState) } subscribeViewState(reducedStates) { hotelView, viewState -> hotelView.render(viewState) } } } Codigo
173. Codigo • Use DiffUtil to render RecyclerView efficiently. • Use Epoxy RecyclerView lib to build complex UI.
174. Codigo
175. Codigo
176. Codigo
177. Codigo
178. Codigo 1. Clean architecture by Uncle Bob 2. Architecting Android the clean way (Repository + Articles) by Fernando Cejas 3. MVI articles series by Hannes Dorfmann 4. Mosby library for mvi by Hannes Dorfmann 5. Using DiffUtil in android RecyclerView 6. Epoxy: Airbnb's View Architecture on Android Some useful links
179. Codigo Thank you