Android における Model-View-Intent アーキテクチャ

Video: https://youtu.be/MIV7Mi9zko8

Android上の開発は非同期の扱いを避ける事はできないです。ネットワーク、フレームワーク、ユーザの操作などから非同期処理が発生してます。油断してしまうとアプリが複雑化してメンテナンスが難しくなります。皆様はネットワークからレスポンスを待っている途中、ユーザが画面をローテーションしても問題ないですか？並行してユーザがいろんな操作しても大丈夫でしょうか？

Model-View-Intent アーキテクチャは非同期処理が発生する前提で考えられたため、すべてがストリームとして扱ってデータの流れを一方通行にするかつ不変オブジェクトを使うのが MVI アーキテクチャの方針です。マルチスレッディングやAndroidのライフサイクルの対応から生じる問題がアーキテクチャによって解決されるおかげでアプリのロジックに集中できるようになり、コードが書きやすく、今後の保守も楽になります！

皆様が MVI アーキテクチャの強みを理解し自分で実現できるようにする目標で Kotlin と RxJava を使って並行処理、画面ローテーション、スナックバーを含んだ画面をどうやって作っていくかを語るつもりです！

Transcript

1. Android ʹ͓͚Δ
   ʊModel-View-Intentʊ
   ΞʔΩςΫνϟ
   Benoît Quenaudon @oldergod
   

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3. “What if the user was a function?” by Andre Staltz
   

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4. “What if the user was a function?” by Andre Staltz
   

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5. user()
   

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6. intent(user())
   

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7. model(intent(user()))
   

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8. view(model(intent(user())))
   

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9. user(view(model(intent(user()))))
   

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10. view(model(intent()))
    

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12. USER
    

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13. sealed class TasksIntent {
    }@
    

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14. sealed class TasksIntent {
    object InitialIntent : TasksIntent()
    }@
    

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16. sealed class TasksIntent {
    object InitialIntent : TasksIntent()
    object RefreshIntent : TasksIntent()
    }@
    

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18. sealed class TasksIntent {
    object InitialIntent : TasksIntent()
    object RefreshIntent : TasksIntent()
    data class ActivateTaskIntent(val task: Task) : TasksIntent()
    data class CompleteTaskIntent(val task: Task) : TasksIntent()
    }@
    

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20. sealed class TasksIntent {
    object InitialIntent : TasksIntent()
    object RefreshIntent : TasksIntent()
    data class ActivateTaskIntent(val task: Task) : TasksIntent()
    data class CompleteTaskIntent(val task: Task) : TasksIntent()
    object ClearCompletedTasksIntent : TasksIntent()
    }@
    

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22. sealed class TasksIntent {
    object InitialIntent : TasksIntent()
    object RefreshIntent : TasksIntent()
    data class ActivateTaskIntent(val task: Task) : TasksIntent()
    data class CompleteTaskIntent(val task: Task) : TasksIntent()
    object ClearCompletedTasksIntent : TasksIntent()
    data class ChangeFilterIntent(val filterType: TasksFilterType) : TasksIntent()
    }@
    

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23. sealed class TasksIntent {
    object InitialIntent : TasksIntent()
    object RefreshIntent : TasksIntent()
    data class ActivateTaskIntent(val task: Task) : TasksIntent()
    data class CompleteTaskIntent(val task: Task) : TasksIntent()
    object ClearCompletedTasksIntent : TasksIntent()
    data class ChangeFilterIntent(val filterType: TasksFilterType) : TasksIntent()
    }@
    

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24. class TasksFragment
    fun intents(): Observable {
    }@
    }@
    

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25. class TasksFragment
    fun intents(): Observable {
    return initialIntent()
    }@a
    private fun initialIntent(): Observable {
    return Observable.just(InitialIntent)
    }
    }@
    

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26. class TasksFragment
    fun_intents():_Observable {
    return Observable.merge(initialIntent(),
    refreshIntent())
    }@a
    private fun refreshIntent(): Observable {
    return RxSwipeRefreshLayout.refreshes(swipeRefreshLayout)
    .map { RefreshIntent }
    }@
    }@
    

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27. class TasksFragment
    fun_intents():_Observable {
    return Observable.merge(initialIntent(),
    refreshIntent(),
    completeTaskIntent(),
    activateTaskIntent(),
    clearCompletedTaskIntent(),
    changeFilterIntent())
    }@
    }@
    

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28. USER
    INTENTS
    Intent
    

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29. intents // Observable
    

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30. intents // Observable
    .map { intent -> actionFromIntent(intent) } // Observable
    

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31. fun actionFromIntent(intent: TasksIntent): TasksAction =
    when (intent) {
    is InitialIntent ->
    is RefreshIntent ->
    is ActivateTaskIntent ->
    is CompleteTaskIntent ->
    is ClearCompletedTasksIntent ->
    is ChangeFilterIntent ->
    }@
    

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32. fun actionFromIntent(intent: TasksIntent): TasksAction =
    when (intent) {
    is InitialIntent ->
    is RefreshIntent ->
    is ActivateTaskIntent ->
    is CompleteTaskIntent ->
    is ClearCompletedTasksIntent ->
    is ChangeFilterIntent ->
    }@
    

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33. fun actionFromIntent(intent: TasksIntent): TasksAction =
    when (intent) {
    is InitialIntent ->
    is RefreshIntent ->
    is ActivateTaskIntent ->
    is CompleteTaskIntent ->
    is ClearCompletedTasksIntent ->
    is ChangeFilterIntent ->
    }@
    

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34. fun actionFromIntent(intent: TasksIntent): TasksAction =
    when (intent) {
    is InitialIntent -> LoadAndFilterTasksAction(TasksFilterType.ALL_TASKS)
    is RefreshIntent ->
    is ActivateTaskIntent ->
    is CompleteTaskIntent ->
    is ClearCompletedTasksIntent ->
    is ChangeFilterIntent ->
    }@
    

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35. fun actionFromIntent(intent: TasksIntent): TasksAction =
    when (intent) {
    is InitialIntent -> LoadAndFilterTasksAction(TasksFilterType.ALL_TASKS)
    is RefreshIntent -> LoadTasksAction
    is ActivateTaskIntent ->
    is CompleteTaskIntent ->
    is ClearCompletedTasksIntent ->
    is ChangeFilterIntent ->
    }@
    

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36. fun actionFromIntent(intent: TasksIntent): TasksAction =
    when (intent) {
    is InitialIntent -> LoadAndFilterTasksAction(TasksFilterType.ALL_TASKS)
    is RefreshIntent -> LoadTasksAction
    is ActivateTaskIntent -> ActivateTaskAction(intent.task)
    is CompleteTaskIntent ->
    is ClearCompletedTasksIntent ->
    is ChangeFilterIntent ->
    }@
    

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37. fun actionFromIntent(intent: TasksIntent): TasksAction =
    when (intent) {
    is InitialIntent -> LoadAndFilterTasksAction(TasksFilterType.ALL_TASKS)
    is RefreshIntent -> LoadTasksAction
    is ActivateTaskIntent -> ActivateTaskAction(intent.task)
    is CompleteTaskIntent -> CompleteTaskAction(intent.task)
    is ClearCompletedTasksIntent ->
    is ChangeFilterIntent ->
    }@
    

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38. fun actionFromIntent(intent: TasksIntent): TasksAction =
    when (intent) {
    is InitialIntent -> LoadAndFilterTasksAction(TasksFilterType.ALL_TASKS)
    is RefreshIntent -> LoadTasksAction
    is ActivateTaskIntent -> ActivateTaskAction(intent.task)
    is CompleteTaskIntent -> CompleteTaskAction(intent.task)
    is ClearCompletedTasksIntent -> ClearCompletedTasksAction
    is ChangeFilterIntent ->
    }@
    

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39. fun actionFromIntent(intent: TasksIntent): TasksAction =
    when (intent) {
    is InitialIntent -> LoadAndFilterTasksAction(TasksFilterType.ALL_TASKS)
    is RefreshIntent -> LoadTasksAction
    is ActivateTaskIntent -> ActivateTaskAction(intent.task)
    is CompleteTaskIntent -> CompleteTaskAction(intent.task)
    is ClearCompletedTasksIntent -> ClearCompletedTasksAction
    is ChangeFilterIntent -> LoadAndFilterTasksAction(intent.filterType)
    }@
    

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40. fun actionFromIntent(intent: TasksIntent): TasksAction =
    when (intent) {
    is InitialIntent -> LoadAndFilterTasksAction(TasksFilterType.ALL_TASKS)
    is RefreshIntent -> LoadTasksAction
    is ActivateTaskIntent -> ActivateTaskAction(intent.task)
    is CompleteTaskIntent -> CompleteTaskAction(intent.task)
    is ClearCompletedTasksIntent -> ClearCompletedTasksAction
    is ChangeFilterIntent -> LoadAndFilterTasksAction(intent.filterType)
    }@
    

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41. private TasksAction actionFromIntent(MviIntent intent) {
    if (intent instanceof InitialIntent) {
    return LoadTasks.loadAndFilter(true, TasksFilterType.ALL_TASKS);
    }
    if (intent instanceof ChangeFilterIntent) {
    return LoadTasks.loadAndFilter(false, ((ChangeFilterIntent) intent).filterType());
    }
    if (intent instanceof RefreshIntent) {
    return LoadTasks.load(((RefreshIntent) intent).forceUpdate());
    }
    if (intent instanceof ActivateTaskIntent) {
    return ActivateTaskAction.create(((ActivateTaskIntent) intent).task());
    }
    if (intent instanceof CompleteTaskIntent) {
    return CompleteTaskAction.create(((CompleteTaskIntent) intent).task());
    }
    if (intent instanceof ClearCompletedTasksIntent) {
    return ClearCompletedTasksAction.create();
    }
    throw new IllegalArgumentException("do not know how to treat this intent " + intent);
    }
    

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42. private TasksAction actionFromIntent(MviIntent intent) {
    if (intent instanceof InitialIntent) {
    return LoadTasks.loadAndFilter(true, TasksFilterType.ALL_TASKS);
    }
    if (intent instanceof ChangeFilterIntent) {
    return LoadTasks.loadAndFilter(false, ((ChangeFilterIntent) intent).filterType());
    }
    if (intent instanceof RefreshIntent) {
    return LoadTasks.load(((RefreshIntent) intent).forceUpdate());
    }
    if (intent instanceof ActivateTaskIntent) {
    return ActivateTaskAction.create(((ActivateTaskIntent) intent).task());
    }
    if (intent instanceof CompleteTaskIntent) {
    return CompleteTaskAction.create(((CompleteTaskIntent) intent).task());
    }
    if (intent instanceof ClearCompletedTasksIntent) {
    return ClearCompletedTasksAction.create();
    }
    throw new IllegalArgumentException("do not know how to treat this intent " + intent);
    }
    

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43. private TasksAction actionFromIntent(MviIntent intent) {
    if (intent instanceof InitialIntent) {
    return LoadTasks.loadAndFilter(true, TasksFilterType.ALL_TASKS);
    }
    if (intent instanceof ChangeFilterIntent) {
    return LoadTasks.loadAndFilter(false, ((ChangeFilterIntent) intent).filterType());
    }
    if (intent instanceof RefreshIntent) {
    return LoadTasks.load(((RefreshIntent) intent).forceUpdate());
    }
    if (intent instanceof ActivateTaskIntent) {
    return ActivateTaskAction.create(((ActivateTaskIntent) intent).task());
    }
    if (intent instanceof CompleteTaskIntent) {
    return CompleteTaskAction.create(((CompleteTaskIntent) intent).task());
    }
    if (intent instanceof ClearCompletedTasksIntent) {
    return ClearCompletedTasksAction.create();
    }
    throw new IllegalArgumentException("do not know how to treat this intent " + intent);
    }
    

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44. private TasksAction actionFromIntent(MviIntent intent) {
    if (intent instanceof InitialIntent) {
    return LoadTasks.loadAndFilter(true, TasksFilterType.ALL_TASKS);
    }
    if (intent instanceof ChangeFilterIntent) {
    return LoadTasks.loadAndFilter(false, ((ChangeFilterIntent) intent).filterType());
    }
    if (intent instanceof RefreshIntent) {
    return LoadTasks.load(((RefreshIntent) intent).forceUpdate());
    }
    if (intent instanceof ActivateTaskIntent) {
    return ActivateTaskAction.create(((ActivateTaskIntent) intent).task());
    }
    if (intent instanceof CompleteTaskIntent) {
    return CompleteTaskAction.create(((CompleteTaskIntent) intent).task());
    }
    if (intent instanceof ClearCompletedTasksIntent) {
    return ClearCompletedTasksAction.create();
    }
    throw new IllegalArgumentException("do not know how to treat this intent " + intent);
    }
    

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45. fun actionFromIntent(intent: TasksIntent): TasksAction =
    when (intent) {
    is InitialIntent -> LoadAndFilterTasksAction(TasksFilterType.ALL_TASKS)
    is RefreshIntent -> LoadTasksAction
    is ActivateTaskIntent -> ActivateTaskAction(intent.task)
    is CompleteTaskIntent -> CompleteTaskAction(intent.task)
    is ClearCompletedTasksIntent -> ClearCompletedTasksAction
    is ChangeFilterIntent -> LoadAndFilterTasksAction(intent.filterType)
    }@
    

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46. sealed class TasksAction {
    data class LoadAndFilterTasksAction(val filterType: TasksFilterType) : TasksAction()
    object LoadTasksAction : TasksAction()
    data class ActivateTaskAction(val task: Task) : TasksAction()
    data class CompleteTaskAction(val task: Task) : TasksAction()
    object ClearCompletedTasksAction : TasksAction()
    }@
    

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47. USER
    INTENTS
    Intent
    Action
    INTENT
    INTERPRETOR
    

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48. Action
    Load and Filter Tasks Logic
    Clear Completed Task Logic
    Complete Task Logic
    Activate Task Logic
    Load Tasks Logic
    Result
    

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49. var actionProcessor: ObservableTransformer =
    ObservableTransformer { actions: Observable ->
    }c
    

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50. var actionProcessor: ObservableTransformer =
    ObservableTransformer { actions: Observable ->
    }c
    

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51. var actionProcessor: ObservableTransformer =
    ObservableTransformer { actions: Observable ->
    actions.publish { shared ->
    }b
    }c
    

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52. var actionProcessor: ObservableTransformer =
    ObservableTransformer { actions: Observable ->
    actions.publish { shared ->
    Observable.merge()a
    }b
    }c
    

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53. var actionProcessor: ObservableTransformer =
    ObservableTransformer { actions: Observable ->
    actions.publish { shared ->
    Observable.merge(
    shared.ofType(LoadTasksAction::class.java).compose(loadTasksProcessor)
    )a
    }b
    }c
    

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54. var actionProcessor: ObservableTransformer =
    ObservableTransformer { actions: Observable ->
    actions.publish { shared ->
    Observable.merge(
    shared.ofType(LoadTasksAction::class.java).compose(loadTasksProcessor),
    shared.ofType(LoadAndFilterTasksAction::class.java).compose(loadAndFilterTasksProcessor)
    )a
    }b
    }c
    

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55. var actionProcessor: ObservableTransformer =
    ObservableTransformer { actions: Observable ->
    actions.publish { shared ->
    Observable.merge(
    shared.ofType(LoadTasksAction::class.java).compose(loadTasksProcessor),
    shared.ofType(LoadAndFilterTasksAction::class.java).compose(loadAndFilterTasksProcessor),
    shared.ofType(ActivateTaskAction::class.java).compose(activateTaskProcessor)
    )a
    }b
    }c
    

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56. var actionProcessor: ObservableTransformer =
    ObservableTransformer { actions: Observable ->
    actions.publish { shared ->
    Observable.merge(
    shared.ofType(LoadTasksAction::class.java).compose(loadTasksProcessor),
    shared.ofType(LoadAndFilterTasksAction::class.java).compose(loadAndFilterTasksProcessor),
    shared.ofType(ActivateTaskAction::class.java).compose(activateTaskProcessor),
    shared.ofType(ClearCompletedTasksAction::class.java).compose(clearCompletedTasksProcessor)
    )a
    }b
    }c
    

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57. var actionProcessor: ObservableTransformer =
    ObservableTransformer { actions: Observable ->
    actions.publish { shared ->
    Observable.merge(
    shared.ofType(LoadTasksAction::class.java).compose(loadTasksProcessor),
    shared.ofType(LoadAndFilterTasksAction::class.java).compose(loadAndFilterTasksProcessor),
    shared.ofType(ActivateTaskAction::class.java).compose(activateTaskProcessor),
    shared.ofType(ClearCompletedTasksAction::class.java).compose(clearCompletedTasksProcessor),
    shared.ofType(CompleteTaskAction::class.java).compose(completeTaskProcessor)
    )a
    }b
    }c
    

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58. var actionProcessor: ObservableTransformer =
    ObservableTransformer { actions: Observable ->
    actions.publish { shared ->
    Observable.merge(
    shared.ofType(LoadTasksAction::class.java).compose(loadTasksProcessor),
    shared.ofType(LoadAndFilterTasksAction::class.java).compose(loadAndFilterTasksProcessor),
    shared.ofType(ActivateTaskAction::class.java).compose(activateTaskProcessor),
    shared.ofType(ClearCompletedTasksAction::class.java).compose(clearCompletedTasksProcessor),
    shared.ofType(CompleteTaskAction::class.java).compose(completeTaskProcessor)
    )a
    }b
    }c
    

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59. val loadTasksProcessor =
    ObservableTransformer { actions: Observable ->
    actions.switchMap {
    tasksRepository.getTasks() // Observable>
    }@
    }@
    

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60. val loadTasksProcessor =
    ObservableTransformer { actions: Observable ->
    actions.switchMap {
    tasksRepository.getTasks() // Observable>
    .startWith(LoadTasksResult.InFlight)
    }@
    }@
    

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61. val loadTasksProcessor =
    ObservableTransformer { actions: Observable ->
    actions.switchMap {
    tasksRepository.getTasks() // Observable>
    .startWith(LoadTasksResult.InFlight)
    .map { tasks -> LoadTasksResult.Success(tasks) }
    }@
    }@
    

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62. val loadTasksProcessor =
    ObservableTransformer { actions: Observable ->
    actions.switchMap {
    tasksRepository.getTasks() // Observable>
    .startWith(LoadTasksResult.InFlight)
    .map { tasks -> LoadTasksResult.Success(tasks) }
    .onErrorReturn { t -> loadTasksResult.Failure(t) }
    }@
    }@
    

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63. val loadTasksProcessor =
    ObservableTransformer { actions: Observable ->
    actions.switchMap {
    tasksRepository.getTasks() // Observable>
    .startWith(LoadTasksResult.InFlight)
    .map { tasks -> LoadTasksResult.Success(tasks) }
    .onErrorReturn { t -> loadTasksResult.Failure(t) }
    .subscribeOn(Schedulers.io())
    .observeOn(AndroidSchedulers.mainThread())
    }@
    }@
    

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64. val loadTasksProcessor =
    ObservableTransformer { actions: Observable ->
    actions.switchMap {
    tasksRepository.getTasks() // Observable>
    .startWith(LoadTasksResult.InFlight)
    .map { tasks -> LoadTasksResult.Success(tasks) }
    .onErrorReturn { t -> loadTasksResult.Failure(t) }
    .subscribeOn(Schedulers.io())
    .observeOn(AndroidSchedulers.mainThread())
    }@
    }@
    

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65. val loadTasksProcessor =
    ObservableTransformer { actions: Observable ->
    actions.switchMap {
    tasksRepository.getTasks() // Observable>
    .map { tasks -> LoadTasksResult.Success(tasks) }
    .onErrorReturn { t -> loadTasksResult.Failure(t) }
    .subscribeOn(Schedulers.io())
    .observeOn(AndroidSchedulers.mainThread())
    .startWith(LoadTasksResult.InFlight)
    }@
    }@
    

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66. var actionProcessor: ObservableTransformer =
    ObservableTransformer { actions: Observable ->
    actions.publish { shared ->
    Observable.merge(
    shared.ofType(LoadTasksAction::class.java).compose(loadTasksProcessor),
    shared.ofType(LoadAndFilterTasksAction::class.java).compose(loadAndFilterTasksProcessor),
    shared.ofType(ActivateTaskAction::class.java).compose(activateTaskProcessor),
    shared.ofType(ClearCompletedTasksAction::class.java).compose(clearCompletedTasksProcessor),
    shared.ofType(CompleteTaskAction::class.java).compose(completeTaskProcessor)
    )a
    }b
    }c
    

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67. intents // Observable
    .map { intent -> actionFromIntent(intent) } // Observable
    .compose(actionProcessor) // Observable
    

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68. USER
    INTENTS
    Intent
    Result Action
    INTENT
    INTERPRETOR
    PROCESSOR
    REPOSITORY
    

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69. θϩ͔Βը໘Λ࡞Δʹ͸ʁ
    

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70. data class TasksViewState(z
    )@
    

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71. data class TasksViewState(z
    val isLoading: Boolean
    )@
    

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72. data class TasksViewState(z
    val isLoading: Boolean,
    val tasksFilterType: TasksFilterType
    )@
    

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73. data class TasksViewState(z
    val isLoading: Boolean,
    val tasksFilterType: TasksFilterType,
    val tasks: List
    )@
    

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74. data class TasksViewState(z
    val isLoading: Boolean,
    val tasksFilterType: TasksFilterType,
    val tasks: List,
    val error: Throwable?
    )@
    

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75. data class TasksViewState(z
    val isLoading: Boolean,
    val tasksFilterType: TasksFilterType,
    val tasks: List,
    val error: Throwable?,
    val taskComplete: Boolean,
    val taskActivated: Boolean,
    val completedTasksCleared: Boolean
    )@
    

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76. data class TasksViewState(z
    val isLoading: Boolean,
    val tasksFilterType: TasksFilterType,
    val tasks: List,
    val error: Throwable?,
    val taskComplete: Boolean,
    val taskActivated: Boolean,
    val completedTasksCleared: Boolean
    )@
    

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77. data class TasksViewState(z
    val isLoading: Boolean,
    val tasksFilterType: TasksFilterType,
    val tasks: List,
    val error: Throwable?,
    val taskComplete: Boolean,
    val taskActivated: Boolean,
    val completedTasksCleared: Boolean
    )@{
    companion object Factory {
    fun default() = TasksViewState(
    isLoading = false,
    tasksFilterType = ALL_TASKS,
    tasks = emptyList(),
    error = null,
    taskComplete = false,
    taskActivated = false,
    completedTasksCleared = false)
    }
    }
    

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78. New
    State
    Result
    Default
    State
    

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79. New
    State
    REDUCER
    Result
    Default
    State
    

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80. New
    State
    REDUCER
    Result
    Previous
    State
    

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81. intents // Observable
    .map { intent -> actionFromIntent(intent) } // Observable
    .compose(actionProcessor) // Observable
    .scan(TasksViewState.default(), reducer) // Observable
    

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82. val reducer = BiFunction
    { previousState: TasksViewState, result: TasksResult ->
    }e
    

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83. val reducer = BiFunction
    { previousState: TasksViewState, result: TasksResult ->
    }e
    

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84. val reducer = BiFunction
    { previousState: TasksViewState, result: TasksResult ->
    when (result)_{
    is LoadTasksResult -> /***/
    is LoadAndFilterTasksResult -> /***/
    is CompleteTaskResult -> /***/
    is ActivateTaskResult -> /***/
    is ClearCompletedTasksResult -> /***/
    }d
    }e
    

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85. val reducer = BiFunction
    { previousState: TasksViewState, result: TasksResult ->
    when (result)_{
    is LoadTasksResult -> {
    when (result) {
    is LoadTasksResult.InFlight -> /***/
    is LoadTasksResult.Failure -> /***/
    is LoadTasksResult.Success -> /***/
    }b
    }c
    is LoadAndFilterTasksResult -> /***/
    is CompleteTaskResult -> /***/
    is ActivateTaskResult -> /***/
    is ClearCompletedTasksResult -> /***/
    }d
    }e
    

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86. val reducer = BiFunction
    { previousState: TasksViewState, result: TasksResult ->
    when (result)_{
    is LoadTasksResult -> {
    when (result) {
    is LoadTasksResult.InFlight -> previousState.copy(isLoading = true)
    is LoadTasksResult.Failure -> /***/
    is LoadTasksResult.Success -> /***/
    }b
    }c
    is LoadAndFilterTasksResult -> /***/
    is CompleteTaskResult -> /***/
    is ActivateTaskResult -> /***/
    is ClearCompletedTasksResult -> /***/
    }d
    }e
    

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87. val reducer = BiFunction
    { previousState: TasksViewState, result: TasksResult ->
    when (result)_{
    is LoadTasksResult -> {
    when (result) {
    is LoadTasksResult.InFlight -> previousState.copy(isLoading = true)
    is LoadTasksResult.Failure -> previousState.copy(isLoading = false,
    error = result.error)
    is LoadTasksResult.Success -> /***/
    }b
    }c
    is LoadAndFilterTasksResult -> /***/
    is CompleteTaskResult -> /***/
    is ActivateTaskResult -> /***/
    is ClearCompletedTasksResult -> /***/
    }d
    }e
    

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88. val reducer = BiFunction
    { previousState: TasksViewState, result: TasksResult ->
    when (result)_{
    is LoadTasksResult -> {
    when (result) {
    is LoadTasksResult.InFlight -> previousState.copy(isLoading = true)
    is LoadTasksResult.Failure -> previousState.copy(isLoading = false,
    error = result.error)
    is LoadTasksResult.Success -> {
    previousState.copy(isLoading = false,
    tasks = result.tasks)
    }a
    }b
    }c
    is LoadAndFilterTasksResult -> /***/
    is CompleteTaskResult -> /***/
    is ActivateTaskResult -> /***/
    is ClearCompletedTasksResult -> /***/
    }d
    }e
    

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89. val reducer = BiFunction
    { previousState: TasksViewState, result: TasksResult ->
    when (result)_{
    is LoadTasksResult -> {
    when (result) {
    is LoadTasksResult.InFlight -> previousState.copy(isLoading = true)
    is LoadTasksResult.Failure -> previousState.copy(isLoading = false,
    error = result.error)
    is LoadTasksResult.Success -> {
    previousState.copy(isLoading = false,
    tasks = result.tasks)
    }a
    }b
    }c
    is LoadAndFilterTasksResult -> /***/
    is CompleteTaskResult -> /***/
    is ActivateTaskResult -> /***/
    is ClearCompletedTasksResult -> /***/
    }d
    }e
    

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90. USER
    INTENTS
    Intent
    Result Action
    State
    INTENT
    INTERPRETOR
    REDUCER
    PROCESSOR
    REPOSITORY
    

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91. intents // Observable
    .map { intent -> actionFromIntent(intent) } // Observable
    .compose(actionProcessor) // Observable
    .scan(TasksViewState.default(), reducer) // Observable
    

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92. intents // Observable
    .map { intent -> actionFromIntent(intent) } // Observable
    .compose(actionProcessor) // Observable
    .scan(TasksViewState.default(), reducer) // Observable
    .subscribe { state -> render(state) }
    

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93. fun render(state: TasksViewState) {
    }u
    

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94. fun render(state: TasksViewState) {
    swipeRefreshLayout.isRefreshing = state.isLoading
    }u
    

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95. fun render(state: TasksViewState) {
    swipeRefreshLayout.isRefreshing = state.isLoading
    if (state.error != null) {
    showLoadingTasksError()
    return
    }a
    }u
    

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96. fun render(state: TasksViewState) {
    swipeRefreshLayout.isRefreshing = state.isLoading
    if (state.error != null) {
    showLoadingTasksError()
    return
    }a
    if (state.taskActivated) {
    showMessage(getString(R.string.task_marked_active))
    }b
    if (state.taskComplete) {
    showMessage(getString(R.string.task_marked_complete))
    }c
    if (state.completedTasksCleared) {
    showMessage(getString(R.string.completed_tasks_cleared))
    }d
    }u
    

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97. if (state.taskActivated) {
    showMessage(getString(R.string.task_marked_active))
    }b
    if (state.taskComplete) {
    showMessage(getString(R.string.task_marked_complete))
    }c
    if (state.completedTasksCleared) {
    showMessage(getString(R.string.completed_tasks_cleared))
    }d
    if (state.tasks.isEmpty()) {
    when (state.tasksFilterType) {z
    ACTIVE_TASKS -> showNoActiveTasks()
    COMPLETED_TASKS -> showNoCompletedTasks()
    ALL_TASKS -> showNoTasks()
    }e
    }_
    }u
    

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98. showMessage(getString(R.string.completed_tasks_cleared))
    }d
    if (state.tasks.isEmpty()) {
    when (state.tasksFilterType) {z
    ACTIVE_TASKS -> showNoActiveTasks()
    COMPLETED_TASKS -> showNoCompletedTasks()
    ALL_TASKS -> showNoTasks()
    }e
    }_else {
    listAdapter.replaceData(state.tasks)
    tasksView.visibility = View.VISIBLE
    noTasksView.visibility = View.GONE
    when (state.tasksFilterType) {
    ACTIVE_TASKS -> showActiveFilterLabel()
    COMPLETED_TASKS -> showCompletedFilterLabel()
    ALL_TASKS -> showAllFilterLabel()
    }g
    }h
    }u
    

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99. fun render(state: TasksViewState) {
    swipeRefreshLayout.isRefreshing = state.isLoading
    if (state.error != null) {
    showLoadingTasksError()
    return
    }a
    if (state.taskActivated) {
    showMessage(getString(R.string.task_marked_active))
    }b
    if (state.taskComplete) {
    showMessage(getString(R.string.task_marked_complete))
    }c
    if (state.completedTasksCleared) {
    showMessage(getString(R.string.completed_tasks_cleared))
    }d
    if (state.tasks.isEmpty()) {
    when (state.tasksFilterType) {
    ACTIVE_TASKS -> showNoActiveTasks()
    COMPLETED_TASKS -> showNoCompletedTasks()
    ALL_TASKS -> showNoTasks()
    }e
    }_else {
    listAdapter.replaceData(state.tasks)
    tasksView.visibility = View.VISIBLE
    noTasksView.visibility = View.GONE
    when (state.tasksFilterType) {
    ACTIVE_TASKS -> showActiveFilterLabel()
    COMPLETED_TASKS -> showCompletedFilterLabel()
    ALL_TASKS -> showAllFilterLabel()
    }g
    }h
    }u
    

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100. USER
     INTENTS
     RENDER
     Intent
     Result Action
     State
     INTENT
     INTERPRETOR
     REDUCER
     PROCESSOR
     REPOSITORY
     

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101. effects sidS
     Side effects
     

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102. USER
     INTENTS
     RENDER
     Intent
     Result Action
     State
     INTENT
     INTERPRETOR
     REDUCER
     PROCESSOR
     REPOSITORY
     

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103. USER
     INTENTS
     RENDER
     Intent
     Result Action
     State
     INTENT
     INTERPRETOR
     REDUCER
     PROCESSOR
     REPOSITORY
     

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104. USER
     INTENTS
     RENDER
     Intent
     Result Action
     State
     INTENT
     INTERPRETOR
     REDUCER
     PROCESSOR
     REPOSITORY
     

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105. USER
     Intent
     Result Action
     State
     INTENT
     INTERPRETOR
     REDUCER
     REPOSITORY
     INTENTS
     RENDER
     PROCESSOR
     

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106. USER
     INTENTS
     RENDER
     Intent
     Result Action
     State
     INTENT
     INTERPRETOR
     REDUCER
     PROCESSOR
     REPOSITORY
     Unidirectional data flow
     

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107. USER
     INTENTS
     RENDER
     Intent
     Result Action
     State
     INTENT
     INTERPRETOR
     REDUCER
     PROCESSOR
     REPOSITORY
     

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108. USER
     USER INTERFACE INTENTS
     RENDER
     Intent
     Result Action
     State
     INTENT
     INTERPRETOR
     REDUCER
     PROCESSOR
     REPOSITORY
     

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109. USER
     USER INTERFACE
     VIEW MODEL
     INTENTS
     RENDER
     Intent
     Result Action
     State
     INTENT
     INTERPRETOR
     REDUCER
     PROCESSOR
     REPOSITORY
     

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110. interface TasksUi {
     fun render(state: TasksViewState)
     fun intents(): Observable
     }@
     interface TasksViewModel {
     fun processIntents(intents: Observable)
     fun states(): Observable
     }@
     

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111. interface TasksUi {
     fun render(state: TasksViewState)
     fun intents(): Observable
     }@
     interface TasksViewModel {
     fun processIntents(intents: Observable)
     fun states(): Observable
     }@
     

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112. interface TasksUi {
     fun render(state: TasksViewState)
     fun intents(): Observable
     }@
     interface TasksViewModel {
     fun processIntents(intents: Observable)
     fun states(): Observable
     }@
     

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113. ฼͔Βͷ͓ి࿩Ͱ͢
     

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114. User: initialIntent()
     App: render()
     User: activateTask(1)
     User: activateTask(2)
     User: refresh()
     Mum:
     Android: you.onStop()
     

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115. User: initialIntent()
     App: render()
     User: activateTask(1)
     User: activateTask(2)
     User: refresh()
     Mum:
     Android: you.onStop()
     

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116. User: initialIntent()
     App: render()
     User: activateTask(1)
     User: activateTask(2)
     User: refresh()
     Mum:
     Android: you.onStop()
     

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117. User: initialIntent()
     App: render()
     User: activateTask(1)
     User: activateTask(2)
     User: refresh()
     Mum:
     Android: app.onStop()
     

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118. USER
     USER INTERFACE
     VIEW MODEL
     INTENTS
     RENDER
     Intent
     Result Action
     State
     INTENT
     INTERPRETOR
     REDUCER
     PROCESSOR
     REPOSITORY
     C
     B
     A
     

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119. INTENTS
     RENDER
     VIEW MODEL
     Intent
     Result Action
     State
     INTENT
     INTERPRETOR
     REDUCER
     PROCESSOR
     REPOSITORY
     B
     C
     A
     USER
     USER INTERFACE
     B
     C
     A
     

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120. USER
     USER INTERFACE
     VIEW MODEL
     INTENTS
     RENDER
     Intent
     Result Action
     State
     INTENT
     INTERPRETOR
     REDUCER
     PROCESSOR
     REPOSITORY
     A
     

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121. Config change ΤϒϦ΢ΣΞ
     

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122. View Slide

123. USER INTERFACE
     VIEW MODEL
     INTENTS
     RENDER
     Intent
     Result Action
     State
     INTENT
     INTERPRETOR
     REDUCER
     PROCESSOR
     REPOSITORY
     

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124. USER INTERFACE
     VIEW MODEL
     SOURCE
     SUBSCRIBER
     

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125. USER INTERFACE
     VIEW MODEL
     SOURCE
     SUBSCRIBER
     

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126. USER INTERFACE
     VIEW MODEL
     SOURCE
     SUBSCRIBER
     SUBJECT
     

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127. USER INTERFACE
     VIEW MODEL
     SOURCE
     SUBSCRIBER
     SUBJECT
     

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128. USER INTERFACE
     VIEW MODEL
     SOURCE
     SUBSCRIBER
     SUBJECT
     

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129. USER INTERFACE
     VIEW MODEL
     SOURCE
     SUBSCRIBER
     SUBJECT
     .autoConnect(0)
     

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130. USER INTERFACE
     VIEW MODEL
     SOURCE
     SUBSCRIBER
     .autoConnect(0) SUBJECT
     

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131. VIEW MODEL
     .autoConnect(0) SUBJECT
     

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132. USER INTERFACE
     VIEW MODEL
     SOURCE
     SUBSCRIBER
     .autoConnect(0) SUBJECT
     

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133. USER INTERFACE
     VIEW MODEL
     SOURCE
     SUBSCRIBER
     .replay(1)
     .autoConnect(0)
     SUBJECT
     

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134. class TasksViewModel : ViewModel() {
     fun processIntents(intents: Observable) {
     }b
     fun states(): Observable {
     }c
     }e
     

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135. class TasksViewModel : ViewModel() {
     private val intentsSubject = PublishSubject.create()
     fun processIntents(intents: Observable) {
     intents.subscribe(intentsSubject)
     }b
     fun states(): Observable {
     }c
     }e
     

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136. class TasksViewModel : ViewModel() {
     private val intentsSubject = PublishSubject.createval states: Observable = compose()
     fun processIntents(intents: Observable) {
     intents.subscribe(intentsSubject)
     }b
     private fun compose(): Observable {
     }c
     }e
     

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137. class TasksViewModel : ViewModel() {
     private val intentsSubject = PublishSubject.create()
     val states: Observable = compose()
     fun processIntents(intents: Observable) {
     intents.subscribe(intentsSubject)
     }b
     private fun compose(): Observable {
     return intentsSubject
     .map { intent -> actionFromIntent(intent) }
     .compose(actionProcessor)
     .scan(TasksViewState.default(), reducer)
     }c
     }e
     

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138. class TasksViewModel : ViewModel() {
     private val intentsSubject = PublishSubject.create()
     val states: Observable = compose()
     fun processIntents(intents: Observable) {
     intents.subscribe(intentsSubject)
     }b
     private fun compose(): Observable {
     return intentsSubject
     .map { intent -> actionFromIntent(intent) }
     .compose(actionProcessor)
     .scan(TasksViewState.default(), reducer)
     .replay(1)
     .autoConnect(0)
     }c
     }e
     

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139. class TasksViewModel : ViewModel() {
     private val intentsSubject = PublishSubject.create()
     val states: Observable = compose()
     fun processIntents(intents: Observable) {
     intents.subscribe(intentsSubject)
     }b
     private fun compose(): Observable {
     return intentsSubject
     .map { intent -> actionFromIntent(intent) }
     .compose(actionProcessor)
     .scan(TasksViewState.default(), reducer)
     .replay(1)
     .autoConnect(0)
     }c
     }e
     

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140. class TasksFragment : Fragment() {
     fun intents(): Observable { /***/ }
     fun render(state: TasksViewState) { /***/ }
     }d
     

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141. class TasksFragment : Fragment() {
     private val viewModel: TasksViewModel by lazy(NONE) {
     ViewModelProviders.of(this).get(TasksViewModel::class.java)
     }a
     fun intents(): Observable { /***/ }
     fun render(state: TasksViewState) { /***/ }
     }d
     

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142. class TasksFragment : Fragment() {
     private val viewModel: TasksViewModel by lazy(NONE) {
     ViewModelProviders.of(this).get(TasksViewModel::class.java)
     }a
     fun intents(): Observable { /***/ }
     fun render(state: TasksViewState) { /***/ }
     override fun onStart() {
     viewModel.states().subscribe(this::render)
     }b
     }d
     

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143. class TasksFragment : Fragment() {
     private val viewModel: TasksViewModel by lazy(NONE) {
     ViewModelProviders.of(this).get(TasksViewModel::class.java)
     }a
     private val disposables = CompositeDisposable()a
     fun intents(): Observable { /***/ }
     fun render(state: TasksViewState) { /***/ }
     override fun onStart() {
     disposables.add(viewModel.states().subscribe(this::render))
     }b
     }d
     

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144. class TasksFragment : Fragment() {
     private val viewModel: TasksViewModel by lazy(NONE) {
     ViewModelProviders.of(this).get(TasksViewModel::class.java)
     }a
     private val disposables = CompositeDisposable()
     fun intents(): Observable { /***/ }
     fun render(state: TasksViewState) { /***/ }
     override fun onStart() {
     disposables.add(viewModel.states().subscribe(this::render))
     viewModel.processIntents(intents())
     }b
     }d
     

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145. class TasksFragment : Fragment() {
     private val viewModel: TasksViewModel by lazy(NONE) {
     ViewModelProviders.of(this).get(TasksViewModel::class.java)
     }a
     private val disposables = CompositeDisposable()
     fun intents(): Observable { /***/ }
     fun render(state: TasksViewState) { /***/ }
     override fun onStart() {
     disposables.add(viewModel.states().subscribe(this::render))
     viewModel.processIntents(intents())
     }b
     override fun onDestroy() {
     disposables.dispose()
     super.onDestroy()
     }c
     }d
     

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146. class TasksFragment : Fragment() {
     private val viewModel: TasksViewModel by lazy(NONE) {
     ViewModelProviders.of(this).get(TasksViewModel::class.java)
     }a
     private val disposables = CompositeDisposable()
     fun intents(): Observable { /***/ }
     fun render(state: TasksViewState) { /***/ }
     override fun onStart() {
     disposables.add(viewModel.states().subscribe(this::render))
     viewModel.processIntents(intents())
     }b
     override fun onDestroy() {
     disposables.dispose()
     super.onDestroy()
     }c
     }d
     

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147. class TasksFragment : Fragment() {
     private val viewModel: TasksViewModel by lazy(NONE) {
     ViewModelProviders.of(this).get(TasksViewModel::class.java)
     }a
     private val disposables = CompositeDisposable()
     fun intents(): Observable { /***/ }
     fun render(state: TasksViewState) { /***/ }
     override fun onStart() {
     disposables.add(viewModel.states().subscribe(this::render))
     viewModel.processIntents(intents())
     }b
     override fun onDestroy() {
     disposables.dispose()
     super.onDestroy()
     }c
     }d
     

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148. class TasksFragment
     fun intents(): Observable {
     return Observable.merge(initialIntent(),
     refreshIntent(),
     completeTaskIntent(),
     activateTaskIntent(),
     clearCompletedTaskIntent(),
     changeFilterIntent())
     }@
     }@
     

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149. class TasksFragment
     fun intents(): Observable {
     return Observable.merge(initialIntent(),
     refreshIntent(),
     completeTaskIntent(),
     activateTaskIntent(),
     clearCompletedTaskIntent(),
     changeFilterIntent())
     }@
     }@
     fun actionFromIntent(intent: TasksIntent): TasksAction =
     when (intent) {
     is InitialIntent -> LoadAndFilterTasksAction
     /***/
     }@
     

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150. private fun compose(): Observable {
     return intentsSubject
     .map { this.actionFromIntent(it) }
     .compose(actionProcessorHolder.actionProcessor)
     .scan(TasksViewState.idle(), reducer)
     .replay(1)
     .autoConnect(0)
     }a
     

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151. private fun compose(): Observable {
     return intentsSubject
     .compose(intentFilter)
     .map { this.actionFromIntent(it) }
     .compose(actionProcessorHolder.actionProcessor)
     .scan(TasksViewState.idle(), reducer)
     .replay(1)
     .autoConnect(0)
     }a
     

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152. private fun compose(): Observable {
     return intentsSubject
     .compose(intentFilter)
     .map { this.actionFromIntent(it) }
     .compose(actionProcessorHolder.actionProcessor)
     .scan(TasksViewState.idle(), reducer)
     .replay(1)
     .autoConnect(0)
     }a
     private val intentFilter: ObservableTransformer
     get() = ObservableTransformer { intents ->
     }z
     

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153. private fun compose(): Observable {
     return intentsSubject
     .compose(intentFilter)
     .map { this.actionFromIntent(it) }
     .compose(actionProcessorHolder.actionProcessor)
     .scan(TasksViewState.idle(), reducer)
     .replay(1)
     .autoConnect(0)
     }a
     private val intentFilter: ObservableTransformer
     get() = ObservableTransformer { intents ->
     intents.publish { shared ->
     Observable.merge()w
     }o
     }z
     

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154. private fun compose(): Observable {
     return intentsSubject
     .compose(intentFilter)
     .map { this.actionFromIntent(it) }
     .compose(actionProcessorHolder.actionProcessor)
     .scan(TasksViewState.idle(), reducer)
     .replay(1)
     .autoConnect(0)
     }a
     private val intentFilter: ObservableTransformer
     get() = ObservableTransformer { intents ->
     intents.publish { shared ->
     Observable.merge(
     shared.ofType(InitialIntent::class.java).take(1)
     )w
     }o
     }z
     

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155. private fun compose(): Observable {
     return intentsSubject
     .compose(intentFilter)
     .map { this.actionFromIntent(it) }
     .compose(actionProcessorHolder.actionProcessor)
     .scan(TasksViewState.idle(), reducer)
     .replay(1)
     .autoConnect(0)
     }a
     private val intentFilter: ObservableTransformer
     get() = ObservableTransformer { intents ->
     intents.publish { shared ->
     Observable.merge(
     shared.ofType(InitialIntent::class.java).take(1),
     shared.notOfType(InitialIntent::class.java)
     )w
     }o
     }z
     

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156. private fun compose(): Observable {
     return intentsSubject
     .compose(intentFilter)
     .map { this.actionFromIntent(it) }
     .compose(actionProcessorHolder.actionProcessor)
     .scan(TasksViewState.idle(), reducer)
     .replay(1)
     .autoConnect(0)
     }a
     private val intentFilter: ObservableTransformer
     get() = ObservableTransformer { intents ->
     intents.publish { shared ->
     Observable.merge(
     shared.ofType(InitialIntent::class.java).take(1),
     shared.notOfType(InitialIntent::class.java)
     )w
     }o
     }z
     

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157. Ͷ͐஌ͬͯΔʁςετʂ
     

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158. USER INTERFACE
     VIEW MODEL
     INTENTS
     RENDER
     Intent
     Result Action
     State
     INTENT
     INTERPRETOR
     REDUCER
     PROCESSOR
     REPOSITORY
     

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159. USER INTERFACE
     VIEW MODEL
     INTENTS
     RENDER
     Intent
     Result Action
     State
     SUBJECT
     PROCESSOR
     REPOSITORY
     

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160. USER INTERFACE
     VIEW MODEL
     INTENTS
     RENDER
     Intent
     Result Action
     State
     TEST OBSERVER
     PROCESSOR
     REPOSITORY
     

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161. USER INTERFACE
     VIEW MODEL
     INTENTS
     RENDER
     Intent
     Result Action
     State
     INTENT
     INTERPRETOR
     REDUCER
     PROCESSOR
     REPOSITORY
     

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162. USER INTERFACE
     VIEW MODEL
     SUBJECT
     TEST OBSERVER
     Intent
     Result Action
     State
     INTENT
     INTERPRETOR
     REDUCER
     PROCESSOR
     REPOSITORY
     

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163. USER INTERFACE
     VIEW MODEL
     INTENTS
     RENDER
     Intent
     Result Action
     State
     INTENT
     INTERPRETOR
     REDUCER
     PROCESSOR
     REPOSITORY
     

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164. USER INTERFACE
     VIEW MODEL
     INTENTS
     RENDER
     Intent
     Result Action
     State
     INTENT
     INTERPRETOR
     REDUCER
     PROCESSOR
     REPOSITORY
     

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165. USER INTERFACE
     VIEW MODEL
     INTENTS
     RENDER
     Intent
     Result Action
     State
     INTENT
     INTERPRETOR
     REDUCER
     PROCESSOR
     REPOSITORY
     

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166. Action
     Load and Filter Tasks Logic
     Clear Completed Task Logic
     Complete Task Logic
     Activate Task Logic
     Load Tasks Logic
     Result PROCESSOR
     

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167. Load and Filter Tasks Logic
     Clear Completed Task Logic
     Complete Task Logic
     Activate Task Logic
     Load Tasks Logic SUBJECT
     TEST OBSERVER
     SUBJECT
     SUBJECT
     SUBJECT
     SUBJECT
     TEST OBSERVER
     TEST OBSERVER
     TEST OBSERVER
     TEST OBSERVER
     

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168. View Slide

169. Fin
     Benoît Quenaudon @oldergod
     

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