MVI

Introduction and application of the reactive MVI architecture in the Android world.

Transcript

1. MVI Iveta Jurčíková, Android Developer at STRV
2. MVI Iveta Jurčíková, Android Developer at STRV
3. MVP/MVVM 2
4. WHAT IS THE “MODEL”? 3
5. WHAT IS THE “MODEL”? • Responsible for handling the business logic • It is where your business logic and application data is stored • It is an interface responsible for managing data • Represents the data and business logic of the app • Gateway to your domain layer or business logic 3
6. WHAT IS THE “MODEL”? • Responsible for handling the business logic • It is where your business logic and application data is stored • It is an interface responsible for managing data • Represents the data and business logic of the app • Gateway to your domain layer or business logic 3
7. MVC 4
8. MVC 5
9. • First defined by Trygve Reenskaug in 1979 MVC 5
10. • First defined by Trygve Reenskaug in 1979 • “Model is responsible for representing state, structure and behaviour of the user’s mental model.” MVC 5
11. • First defined by Trygve Reenskaug in 1979 • “Model is responsible for representing state, structure and behaviour of the user’s mental model.” • “A View presents information that it retrieves from one or more model objects.” MVC 5
12. • First defined by Trygve Reenskaug in 1979 • “Model is responsible for representing state, structure and behaviour of the user’s mental model.” • “A View presents information that it retrieves from one or more model objects.” • “Let the View register with the Model as being a dependent of the Model, and let the Model send appropriate messages to its dependents whenever it changes.” MVC 5
13. MVI 6
15. 7 Beer?
16. 7 Yes, sure!
17. 7 So, let’s go! I pay!
18. 7 Great! I am ready!
22. 9 Input Output Output Input
23. Input Output 10
24. 11 Input Output function()
25. 12 Input Output Output Input
26. 13 intent() model() view() user()
27. 14 user()
28. 15 intent(user())
29. 16 model(intent(user()))
30. 17 view(model(intent(user())))
31. 18 user(view(model(intent(user()))))
32. 19 intent(user(view(model(intent(user())))))
33. 20 view(model(intent(user())))
34. 21 view(model(intent()))
35. 22 PURE FUNCTION view(model(intent())))
36. PURE FUNCTION 23 view(model(intent())))
37. PURE FUNCTION 23 view(model(intent()))) fun sum(a: Int, b: Int): Int { return a + b }}
38. PURE FUNCTION 23 view(model(intent()))) fun sum(a: Int, b: Int): Int { return a + b }} fun sum(a: Int, b: Int): Int { println(a + b) return a + b }
39. PURE FUNCTION 24 view(model(intent()))) fun sum(a: Int, b: Int): Int { return a + b }} var b = 0 fun sum(a: Int): Int { return a + b }
40. PURE FUNCTION 24 view(model(intent()))) fun sum(a: Int, b: Int): Int { return a + b }} var b = 0 fun sum(a: Int): Int { return a + b }
41. 25 intent() model() view() user()
42. 26 intent() model() view() user()
43. 27 intent() model() view() user()
44. 28 intent() model() view() user()
45. STATE 29
46. STATE 29 • Immutable data structure
47. STATE 29 • Immutable data structure • Single source of truth
48. STATE 29 • Immutable data structure • Single source of truth • intent() for each change ➡ Clear understanding of what happens in the app
49. STATE 30
50. STATE 30 class CountryListViewState())
51. STATE 30 class CountryListViewState(( val isLoading = true))
52. STATE 31 class CountryListViewState(( val isLoading = true))
53. STATE 31 class CountryListViewState(( val isLoading = true))
54. STATE 31 class CountryListViewState(( val isLoading = false))
55. STATE 31 class CountryListViewState(( val isLoading = false,,, val countries = emptyList()))
56. STATE 32 1 x 1 class CountryListViewState(( val isLoading = false,,, val countries = emptyList()))
57. STATE 32 1 x 1 class CountryListViewState(( val isLoading = false,,, val countries = emptyList()))
58. STATE 32 1 x 1 class CountryListViewState(( val isLoading = false,, , val countries = emptyList(), val isRefreshing = true))
59. STATE 33 class CountryListViewState(( val isLoading = false,, , val countries = emptyList(), val isRefreshing = true))
60. STATE 33 class CountryListViewState(( val isLoading = false,, , val countries = emptyList(), val isRefreshing = true))
61. class CountryListViewState(( val isLoading = false,, , val countries = emptyList(), val isRefreshing = true, val error = `UnknownHostException…`)) STATE 33
62. class CountryListViewState(( val isLoading = false,, , val countries = emptyList(), val isRefreshing = true, val error = `UnknownHostException…`)) STATE 33
63. 34 STATE PROBLEM
64. STATE PROBLEM class MyProfileViewModel {{ val progress = MutableLiveData() val myProfile = MutableLiveData() override fun loadProfile() {{ progress.value = true subscriptions.add( myProfileInteractor.getLoggedUser().subscribe(( object : Subscriber<UserEntity>() {{ override fun onCompleted() {{ progress.value = false }} override fun onError(e: Throwable) {{ handleError(e) }} override fun onNext(userEntity: UserEntity) {{ userInteractor.setUser(userEntity) myProfile.value = userEntity }} }} )) )) }} override fun handleEditProfileClick() {{ /***/ }} }} 35
65. STATE PROBLEM class MyProfileViewModel {{ val progress = MutableLiveData() val myProfile = MutableLiveData() override fun loadProfile() {{ progress.value = true subscriptions.add( myProfileInteractor.getLoggedUser().subscribe(( object : Subscriber<UserEntity>() {{ override fun onCompleted() {{ progress.value = false }} override fun onError(e: Throwable) {{ handleError(e) }} override fun onNext(userEntity: UserEntity) {{ userInteractor.setUser(userEntity) myProfile.value = userEntity }} }} )) )) }} override fun handleEditProfileClick() {{ /***/ }} }} 35 STATE PROBLEM
66. class MyProfileViewModel {{ val progress = MutableLiveData() val myProfile = MutableLiveData() override fun loadProfile() {{ progress.value = true subscriptions.add( myProfileInteractor.getLoggedUser().subscribe(( object : Subscriber<UserEntity>() {{ override fun onCompleted() {{ progress.value = false }} override fun onError(e: Throwable) {{ handleError(e) }} override fun onNext(userEntity: UserEntity) {{ userInteractor.setUser(userEntity) myProfile.value = userEntity }} }} )) )) }} override fun handleEditProfileClick() {{ /***/ }} }} 36 STATE PROBLEM
67. 37 STATE PROBLEM class MyProfileViewModel {{ val progress = MutableLiveData() val myProfile = MutableLiveData() override fun loadProfile() {{ progress.value = true subscriptions.add( myProfileInteractor.getLoggedUser().subscribe(( object : Subscriber<UserEntity>() {{ override fun onCompleted() {{ progress.value = false }} override fun onError(e: Throwable) {{ handleError(e) }} override fun onNext(userEntity: UserEntity) {{ userInteractor.setUser(userEntity) myProfile.value = userEntity }} }} )) )) }} override fun handleEditProfileClick() {{ /***/ }} }}
68. 38 STATE PROBLEM class MyProfileViewModel {{ val progress = MutableLiveData() val myProfile = MutableLiveData() override fun loadProfile() {{ progress.value = true subscriptions.add(( myProfileInteractor.getLoggedUser().subscribe(( object : Subscriber<UserEntity>() {{ override fun onCompleted() {{ progress.value = false }} override fun onError(e: Throwable) {{ handleError(e) }} override fun onNext(userEntity: UserEntity) {{ userInteractor.setUser(userEntity) myProfile.value = userEntity }} }} )) )) }} override fun handleEditProfileClick() {{ /***/ }} }}
69. 39 STATE PROBLEM class MyProfileViewModel {{ val progress = MutableLiveData() val myProfile = MutableLiveData() override fun loadProfile() {{ progress.value = true subscriptions.add( myProfileInteractor.getLoggedUser().subscribe(( object : Subscriber<UserEntity>() {{ override fun onCompleted() {{ progress.value = false }} override fun onError(e: Throwable) {{ handleError(e) }} override fun onNext(userEntity: UserEntity) {{ userInteractor.setUser(userEntity) myProfile.value = userEntity }} }} )) )) }} override fun handleEditProfileClick() {{ /***/ }} }}
70. 40 STATE PROBLEM
71. 40 STATE PROBLEM
72. 41 intent() model() view() user()
73. 42 intent() model() view() user()
74. 42 side effects intent() model() view() user()
75. 43 16 x 9 / 1 x 1
76. DEMO 44
77. 358px x 640px
78. 358px x 640px
80. 47 INTENTS
81. 47 • Start the screen INTENTS
82. 47 • Start the screen • Refresh the screen INTENTS
83. 47 • Start the screen • Refresh the screen • Add country to the favourite list INTENTS
84. 47 • Start the screen • Refresh the screen • Add country to the favourite list • Remove country from the favourite list INTENTS
85. 47 • Start the screen • Refresh the screen • Add country to the favourite list • Remove country from the favourite list • Apply filters INTENTS
86. 48 INTENTS sealed class CountryListIntent {{ object InitialIntent : CountryListIntent() object SwipeToRefreshIntent : CountryListIntent() data class AddToFavoriteIntent( val countryName: String) : CountryListIntent() data class RemoveFromFavoriteIntent( val countryName: String) : CountryListIntent() data class ChangeFilterIntent( val filterType: FilterType) : CountryListIntent() }}
87. 48 INTENTS sealed class CountryListIntent {{ object InitialIntent : CountryListIntent() object SwipeToRefreshIntent : CountryListIntent() data class AddToFavoriteIntent( val countryName: String) : CountryListIntent() data class RemoveFromFavoriteIntent( val countryName: String) : CountryListIntent() data class ChangeFilterIntent( val filterType: FilterType) : CountryListIntent() }}
90. 50 ACTIVITY/FRAGMENT intent()
91. class CountryListFragment {{ fun intents() = initialIntent private val initialIntent by lazy {{ Observable.just(CountryListIntent.InitialIntent)) }} }} 51
92. class CountryListFragment {{ fun intents() = Observable.merge(( initialIntent, swipeToRefreshIntent )) private val swipeToRefreshIntent by lazy { binding.swiperefresh.refreshes() .map { SwipeToRefreshIntent } }} }} 52
93. 53 class CountryListFragment {{ fun intents() = Observable.merge(( initialIntent, swipeToRefreshIntent, addToFavoriteIntent, removeFromFavoriteIntent ).mergeWith(changeFilterIntent)} }}}
94. 54 intent() ACTIVITY/FRAGMENT
95. 54 intent() ACTIVITY/FRAGMENT
96. 55 16 x 9 / 1 x 1 Intent Action USER INTERFACE VIEW MODEL intent() actionFromIntent()
97. 56 ACTIONS
98. • Load countries • Add country to the favorite list • Remove country from the favorite list 57 ACTIONS
99. sealed class { data class ( val isRefreshing: Boolean, val filterType: FilterType? ) : CountryListAction() data class ( val countryName: String ) : CountryListAction() data class ( val countryName: String ) : CountryListAction() } RemoveFromFavoriteAction AddToFavoriteAction 58 LoadCountriesAction CountryListAction ACTIONS
100. class CountryListViewModel {{ val actions: Observable<CountryListViewState> = intentsSubject .map(this::actionFromIntent) fun actionFromIntent(intent: CountryListIntent): = when (intent) {{ is InitialIntent -> (false) is SwipeToRefreshIntent -> (true) is ChangeFilterIntent -> (intent.filterType) is AddToFavoriteIntent -> (intent.countryName) is RemoveFromFavoriteIntent -> (intent.countryName) }} }} RemoveFromFavoriteAction AddToFavoriteAction 59 LoadCountriesAction LoadCountriesAction LoadCountriesAction CountryListAction ACTIONS
101. class CountryListViewModel {{ val actions: Observable<CountryListViewState> = intentsSubject .map(this::actionFromIntent) fun actionFromIntent(intent: CountryListIntent): = when (intent) {{ is InitialIntent -> (false) is SwipeToRefreshIntent -> (true) is ChangeFilterIntent -> (intent.filterType) is AddToFavoriteIntent -> (intent.countryName) is RemoveFromFavoriteIntent -> (intent.countryName) }} }} RemoveFromFavoriteAction AddToFavoriteAction 60 LoadCountriesAction LoadCountriesAction LoadCountriesAction CountryListAction ACTIONS
102. class CountryListViewModel {{ val actions: Observable<CountryListViewState> = intentsSubject .map(this::actionFromIntent) fun actionFromIntent(intent: CountryListIntent): = when (intent) {{ is InitialIntent -> (false) is SwipeToRefreshIntent -> (true) is ChangeFilterIntent -> (intent.filterType) is AddToFavoriteIntent -> (intent.countryName) is RemoveFromFavoriteIntent -> (intent.countryName) }} }} RemoveFromFavoriteAction AddToFavoriteAction 61 LoadCountriesAction LoadCountriesAction LoadCountriesAction CountryListAction ACTIONS
103. class CountryListViewModel {{ val actions: Observable<CountryListViewState> = intentsSubject .map(this::actionFromIntent) fun actionFromIntent(intent: CountryListIntent): = when (intent) {{ is InitialIntent -> (false) is SwipeToRefreshIntent -> (true) is ChangeFilterIntent -> (intent.filterType) is AddToFavoriteIntent -> (intent.countryName) is RemoveFromFavoriteIntent -> (intent.countryName) }} }} RemoveFromFavoriteAction AddToFavoriteAction 61 LoadCountriesAction LoadCountriesAction LoadCountriesAction CountryListAction ACTIONS
104. 62 sealed class CountryListIntent { object InitialIntent : CountryListIntent() object SwipeToRefresh : CountryListIntent() data class ChangeFilterIntent( val filterType: FilterType): CountryListIntent() data class AddToFavoriteIntent( val countryName: String): CountryListIntent() data class RemoveFromFavoriteIntent( val countryName: String): CountryListIntent() } sealed class CountryListAction { data class LoadCountriesAction( val isRefreshing: Boolean, val filterType: FilterType) : CountryListAction() data class AddToFavoriteAction( val countryName: String) : CountryListAction() data class RemoveFromFavoriteAction( val countryName: String) : CountryListAction() } 5 3
105. 63 16 x 9 / 1 x 1 Intent Action USER INTERFACE VIEW MODEL intent() actionFromIntent()
106. 64 intent() model() view() user()
107. 65 intent() model() user() view()
108. 66 16 x 9 / 1 x 1 Intent Action USER INTERFACE VIEW MODEL intent() actionFromIntent()
109. 66 16 x 9 / 1 x 1 Intent Action USER INTERFACE VIEW MODEL intent() actionFromIntent()
110. 67 16 x 9 / 1 x 1 Intent Action Result USER INTERFACE VIEW MODEL DATABASE/API intent() actionFromIntent() actionProcessor()
111. 68 Action Result
112. 68 Action Result LOAD COUNTRIES ADD TO FAVORITE REMOVE FROM FAVORITE
113. 69 class CountryListInteractor { val actionProcessor = ObservableTransformer<CountryListAction, CountryListResult> { actions -> actions.publish { selector -> Observable.merge(( )) }} }} }}
114. 70 class CountryListInteractor { val actionProcessor = ObservableTransformer<CountryListAction, CountryListResult> { actions -> actions.publish { selector -> Observable.merge(( selector.ofType(LoadCountriesAction::class.java).compose( ), selector.ofType(AddToFavoriteAction::class.java).compose(addToFavorite), selector.ofType(RemoveFromFavoriteAction::class.java).compose(removeFromFavorite) )) }} }}} }} loadCountries
115. 71 val = ObservableTransformer<LoadCountriesAction, CountryListResult> { actions -> actions.flatMap { action -> }} }}} loadCountries
116. 72 val loadCountries = ObservableTransformer<LoadCountriesAction, CountryListResult> { actions -> actions.flatMap { action -> countryRepository.getAllCountries() }} }}}
117. 73 val loadCountries = ObservableTransformer<LoadCountriesAction, CountryListResult> { actions -> actions.flatMap { action -> countryRepository.getAllCountries() .map { countries -> LoadCountriesResult.Success(countries) } }} }}}
118. 74 val loadCountries = ObservableTransformer<LoadCountriesAction, CountryListResult> { actions -> actions.flatMap { action -> countryRepository.getAllCountries() .map { countries -> LoadCountriesResult.Success(countries) } .onErrorReturn { LoadCountriesResult.Failure(it) } }} }}}
119. 75 val loadCountries = ObservableTransformer<LoadCountriesAction, CountryListResult> { actions -> actions.flatMap { action -> countryRepository.getAllCountries() .map { countries -> LoadCountriesResult.Success(countries) } .onErrorReturn { LoadCountriesResult.Failure(it) } .subscribeOn(Schedulers.io()) .observeOn(AndroidSchedulers.mainThread()) }} }}}
120. 76 val loadCountries = ObservableTransformer<LoadCountriesAction, CountryListResult> { actions -> actions.flatMap { action -> countryRepository.getAllCountries() .map { countries -> LoadCountriesResult.Success(countries) } .onErrorReturn { LoadCountriesResult.Failure(it) } .subscribeOn(Schedulers.io()) .observeOn(AndroidSchedulers.mainThread()) .startWith(LoadCountriesResult.InProgress(action.isRefreshing)) }} }}}
121. 77 16 x 9 / 1 x 1 Intent Action Result USER INTERFACE VIEW MODEL DATABASE/API intent() actionFromIntent() actionProcessor()
122. 77 16 x 9 / 1 x 1 Intent Action Result USER INTERFACE VIEW MODEL DATABASE/API intent() actionFromIntent() actionProcessor()
123. 78 16 x 9 / 1 x 1 Intent Action Result State USER INTERFACE VIEW MODEL DATABASE/API intent() actionFromIntent() actionProcessor() reducer()
124. REDUX 79
125. REDUX • A predicable state container 79
126. REDUX • A predicable state container • Basics 79
127. REDUX • A predicable state container • Basics • State 79
128. REDUX • A predicable state container • Basics • State • Action 79
129. REDUX • A predicable state container • Basics • State • Action • Reducer 79
130. REDUX • A predicable state container • Basics • State • Action • Reducer 79 Result Old State New State f(previousState, action) = newState
131. REDUX • A predicable state container • Basics • State • Action • Reducer • Advanced 79 Result Old State New State f(previousState, action) = newState
132. REDUX • A predicable state container • Basics • State • Action • Reducer • Advanced • Middleware 79 Result Old State New State f(previousState, action) = newState
133. REDUX • A predicable state container • Basics • State • Action • Reducer • Advanced • Middleware 79 Result Old State New State f(previousState, action) = newState
134. class CountryListViewModel { val reducer = BiFunction { previousState: CountryListViewState, result: CountryListResult -> when (result) {{ is LoadCountriesResult -> when (result) {{ is LoadCountriesResult.Success -> /***/ is LoadCountriesResult.Failure -> 80 /***/ /***/ is LoadCountriesResult.InProgress -> }} is AddToFavoriteResult -> /***/ is RemoveFromFavoriteResult -> /***/ }} }} }}
135. /***/ /***/ is LoadCountriesResult.Failure -> is LoadCountriesResult.InProgress -> }} is AddToFavoriteResult -> /***/ is RemoveFromFavoriteResult -> /***/ }} }} }} class CountryListViewModel { val reducer = BiFunction { previousState: CountryListViewState, result: CountryListResult -> when (result) {{ is LoadCountriesResult -> when (result) {{ is LoadCountriesResult.Success -> {1 previousState.copy(1 isLoading = false, isRefreshing = false, countries = result.countries, error = null )1 }} 81
136. /***/ /***/ is LoadCountriesResult.Failure -> is LoadCountriesResult.InProgress -> }} is AddToFavoriteResult -> /***/ is RemoveFromFavoriteResult -> /***/ }} }} }} class CountryListViewModel { val reducer = BiFunction { previousState: CountryListViewState, result: CountryListResult -> when (result) {{ is LoadCountriesResult -> when (result) {{ is LoadCountriesResult.Success -> {1 previousState.copy(1 isLoading = false, isRefreshing = false, countries = result.countries, error = null )1 }} 81
137. class CountryListViewModel { val reducer = BiFunction { previousState: CountryListViewState, result: CountryListResult -> when (result) {{ is LoadCountriesResult -> when (result) {{ is LoadCountriesResult.Success -> {1 previousState.copy(1 isLoading = false, isRefreshing = false, countries = result.countries, error = null )1 }} {2 2previousState.copy(2 2isLoading = false, error = result.error )2 }} /***/ is LoadCountriesResult.InProgress -> }} is AddToFavoriteResult -> /***/ is RemoveFromFavoriteResult -> /***/ }} }} }} 82 is LoadCountriesResult.Failure ->
138. class CountryListViewModel { val reducer = BiFunction { previousState: CountryListViewState, result: CountryListResult -> when (result) {{ is LoadCountriesResult -> when (result) {{ is LoadCountriesResult.Success -> {1 previousState.copy(1 isLoading = false, isRefreshing = false, countries = result.countries, error = null )1 }} {2 2previousState.copy(2 2isLoading = false, error = result.error )2 }} /***/ is LoadCountriesResult.InProgress -> }} is AddToFavoriteResult -> /***/ is RemoveFromFavoriteResult -> /***/ }} }} }} 82 is LoadCountriesResult.Failure ->
139. {3 if (result.isRefreshing) {3 3previousState.copy(3 3isLoading = false, isRefreshing = true )31 } else {3 previousState.copy(3 isLoading = true, isRefreshing = false )32 }3 }3 83 is LoadCountriesResult.InProgress -> val reducer = BiFunction { previousState: CountryListViewState, result: CountryListResult -> when (result) {{ is LoadCountriesResult -> when (result) {{ is LoadCountriesResult.Success -> {2 2previousState.copy(2 2isLoading = false, error = result.error )2 }} is LoadCountriesResult.Failure -> }} is AddToFavoriteResult -> /***/ is RemoveFromFavoriteResult -> /***/ }} }} }} {1 previousState.copy(1 isLoading = false, isRefreshing = false, countries = result.countries, error = null )1 }}
140. {3 if (result.isRefreshing) {3 3previousState.copy(3 3isLoading = false, isRefreshing = true )31 } else {3 previousState.copy(3 isLoading = true, isRefreshing = false )32 }3 }3 83 is LoadCountriesResult.InProgress -> val reducer = BiFunction { previousState: CountryListViewState, result: CountryListResult -> when (result) {{ is LoadCountriesResult -> when (result) {{ is LoadCountriesResult.Success -> {2 2previousState.copy(2 2isLoading = false, error = result.error )2 }} is LoadCountriesResult.Failure -> }} is AddToFavoriteResult -> /***/ is RemoveFromFavoriteResult -> /***/ }} }} }} {1 previousState.copy(1 isLoading = false, isRefreshing = false, countries = result.countries, error = null )1 }}
141. 84 16 x 9 / 1 x 1 Intent Action Result State USER INTERFACE VIEW MODEL DATABASE/API intent() actionFromIntent() actionProcessor() reducer()
142. 84 16 x 9 / 1 x 1 Intent Action Result State USER INTERFACE VIEW MODEL DATABASE/API intent() actionFromIntent() actionProcessor() reducer()
143. 85 16 x 9 / 1 x 1 Intent Action Result State USER INTERFACE VIEW MODEL DATABASE/API intent() actionFromIntent() actionProcessor() render() reducer()
144. 86 } } } class CountryListFragment { fun render(state: CountryListViewState) { if (state.message != null) { showMessage(state.message) }} if (state.error != null) { showErrorMessage(state.error) binding.progress.visibility = if (state.isLoading) View.VISIBLE else View.GONE binding.tvEmpty.visibility = if (!state.isLoading && state.countries.isEmpty()) View.VISIBLE else View.GONE binding.swiperefresh.isRefreshing = state.isRefreshing (binding.rvCountries.adapter as ListAdapter<Country, CountryViewHolder>) .submitList(state.countries)
145. if (state.message != null) { showMessage(state.message) }} if (state.error != null) { showErrorMessage(state.error) 87 } } } class CountryListFragment { fun render(state: CountryListViewState) { binding.model = state
146. 88 16 x 9 / 1 x 1 Intent Action Result State USER INTERFACE VIEW MODEL DATABASE/API intent() actionFromIntent() actionProcessor() render() reducer()
147. 88 16 x 9 / 1 x 1 Intent Action Result State USER INTERFACE VIEW MODEL DATABASE/API intent() actionFromIntent() actionProcessor() render() reducer()
148. 89 Intent Action Result State DATABASE/API
149. 90 Intent Action Result State DATABASE/API intents()
150. 90 Intent Action Result State DATABASE/API intents()
151. 91 Intent Action Result State DATABASE/API intents() .map { intent -> actionFromIntent(intent) }
152. 92 Intent Action Result State DATABASE/API intents() .map { intent -> actionFromIntent(intent) } .compose(countryListInteractor.actionProcessor)
153. 92 Intent Action Result State DATABASE/API intents() .map { intent -> actionFromIntent(intent) } .compose(countryListInteractor.actionProcessor)
154. 93 Intent Action Result State DATABASE/API intents() .map { intent -> actionFromIntent(intent) } .compose(countryListInteractor.actionProcessor) .scan(CountryListViewState.idle(), reducer)
155. 93 Intent Action Result State DATABASE/API intents() .map { intent -> actionFromIntent(intent) } .compose(countryListInteractor.actionProcessor) .scan(CountryListViewState.idle(), reducer)
156. 94 Intent Action Result State DATABASE/API intents() .map { intent -> actionFromIntent(intent) } .compose(countryListInteractor.actionProcessor) .scan(CountryListViewState.idle(), reducer) .subscribe { viewState -> render(viewState) }
157. 94 Intent Action Result State DATABASE/API intents() .map { intent -> actionFromIntent(intent) } .compose(countryListInteractor.actionProcessor) .scan(CountryListViewState.idle(), reducer) .subscribe { viewState -> render(viewState) } Unidirectional data flow
158. 94 Intent Action Result State DATABASE/API intents() .map { intent -> actionFromIntent(intent) } .compose(countryListInteractor.actionProcessor) .scan(CountryListViewState.idle(), reducer) .subscribe { viewState -> render(viewState) } Unidirectional data flow More predictable Easier to understand
159. CONFIG CHANGE 95
160. CONFIG CHANGE • Just display the latest state 95
161. NAVIGATION • Is there a state change or not? 96
162. LIBRARIES • Mobius - Spotify • MvRx - Airbnb • StateMachine - Tinder • MVICore - Badoo • RxRedux - Freeletics • Elmdroid - Inventi 97
163. 98 SUMMARY
164. 98 PROS SUMMARY
165. 98 PROS ✅ No state problem SUMMARY
166. 98 PROS ✅ No state problem ✅ Unidirectional data flow SUMMARY
167. 98 PROS ✅ No state problem ✅ Unidirectional data flow ✅ Immutability SUMMARY
168. 98 PROS ✅ No state problem ✅ Unidirectional data flow ✅ Immutability ✅ Thread safety SUMMARY
169. 98 PROS ✅ No state problem ✅ Unidirectional data flow ✅ Immutability ✅ Thread safety ✅ Share-ability SUMMARY
170. 98 PROS ✅ No state problem ✅ Unidirectional data flow ✅ Immutability ✅ Thread safety ✅ Share-ability ✅ Debuggability SUMMARY
171. 98 PROS ✅ No state problem ✅ Unidirectional data flow ✅ Immutability ✅ Thread safety ✅ Share-ability ✅ Debuggability ✅ Decoupled logic SUMMARY
172. 98 PROS ✅ No state problem ✅ Unidirectional data flow ✅ Immutability ✅ Thread safety ✅ Share-ability ✅ Debuggability ✅ Decoupled logic ✅ Testability SUMMARY
173. 98 PROS ✅ No state problem ✅ Unidirectional data flow ✅ Immutability ✅ Thread safety ✅ Share-ability ✅ Debuggability ✅ Decoupled logic ✅ Testability CONS SUMMARY
174. 98 PROS ✅ No state problem ✅ Unidirectional data flow ✅ Immutability ✅ Thread safety ✅ Share-ability ✅ Debuggability ✅ Decoupled logic ✅ Testability CONS ❌ Lot of boilerplate SUMMARY
175. 98 PROS ✅ No state problem ✅ Unidirectional data flow ✅ Immutability ✅ Thread safety ✅ Share-ability ✅ Debuggability ✅ Decoupled logic ✅ Testability CONS ❌ Lot of boilerplate ❌ Complexity SUMMARY
176. 98 PROS ✅ No state problem ✅ Unidirectional data flow ✅ Immutability ✅ Thread safety ✅ Share-ability ✅ Debuggability ✅ Decoupled logic ✅ Testability CONS ❌ Lot of boilerplate ❌ Complexity ❌ Objects creation SUMMARY
177. 98 PROS ✅ No state problem ✅ Unidirectional data flow ✅ Immutability ✅ Thread safety ✅ Share-ability ✅ Debuggability ✅ Decoupled logic ✅ Testability CONS ❌ Lot of boilerplate ❌ Complexity ❌ Objects creation ❌ SingleLiveEvents SUMMARY
178. 98 PROS ✅ No state problem ✅ Unidirectional data flow ✅ Immutability ✅ Thread safety ✅ Share-ability ✅ Debuggability ✅ Decoupled logic ✅ Testability CONS ❌ Lot of boilerplate ❌ Complexity ❌ Objects creation ❌ SingleLiveEvents ❌ No google supported SUMMARY
181. “If you like the code you have written a year ago, you haven’t learned enough this year.“ 101 Someone really smart
182. DEMO • https://github.com/ywett02/CountriesMVI 102
183. AND WHAT ABOUT COROUTINES…? 103
184. 104 Coroutines RxJava
186. COROUTINES 106
187. COROUTINES • Asynchronous programming 106
188. COROUTINES • Asynchronous programming • No functional by default 106
189. RXJAVA • Reactive programming • Funcional programming • Backpressure 107
190. RXJAVA VS COROUTINES 108
192. THAT’S IT iveta.jurcikova@strv.com / @/IJurcikova
193. QUESTIONS
194. THANK YOU www.strv.com / @strvcom
195. REFERENCES • Benoît Quenaudon. Model-View-Intent for Android • Garima Jain. Why MVI? Model View Intent -- The curious case of yet another pattern • Hannes Dorfmann. Reactive apps with Model-View-Intent • Kausik Gopal. RxJava by Example - Volume 3, the Multicast Edition • Jake Wharton. Managing State with RxJava • Hannes Dorfmann. Android Software Architecture by Example • Andre Staltz. What if the user was a function? • Dan Lew. Don't break the chain: use RxJava's compose() operator. • kotlinx.coroutines • Christina Lee. Coroutines By Example • Andrea Bresolin. Kotlin coroutines vs RxJava: an initial performance test • Redux documentation 113