Re-architect state handling code

app/build.gradle

@@ -339,6 +339,7 @@ dependencies {
     implementation Deps.androidx_navigation_ui
     implementation Deps.androidx_recyclerview
     implementation Deps.androidx_lifecycle_viewmodel_ktx
+    implementation Deps.androidx_lifecycle_viewmodel_ss
 
     implementation Deps.autodispose
 

app/src/main/java/org/mozilla/fenix/browser/BrowserFragment.kt

@@ -132,6 +132,7 @@ class BrowserFragment : Fragment(), BackHandler, CoroutineScope,
 
         toolbarComponent = ToolbarComponent(
             view.browserLayout,
+            this,
             ActionBusFactory.get(this), customTabSessionId,
             (activity as HomeActivity).browsingModeManager.isPrivate,
             SearchState("", getSessionById()?.searchTerms ?: "", isEditing = false),
@@ -156,6 +157,7 @@ class BrowserFragment : Fragment(), BackHandler, CoroutineScope,
 
         QuickActionComponent(
             view.nestedScrollQuickAction,
+            this,
             ActionBusFactory.get(this),
             QuickActionState(
                 readable = getSessionById()?.readerable ?: false,

app/src/main/java/org/mozilla/fenix/collections/CollectionCreationComponent.kt

@@ -5,13 +5,18 @@ package org.mozilla.fenix.collections
    file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
 import android.view.ViewGroup
+import androidx.fragment.app.Fragment
+import androidx.lifecycle.ViewModel
+import androidx.lifecycle.ViewModelProvider
+import io.reactivex.Observable
 import org.mozilla.fenix.home.sessioncontrol.Tab
 import org.mozilla.fenix.home.sessioncontrol.TabCollection
 import org.mozilla.fenix.mvi.Action
 import org.mozilla.fenix.mvi.ActionBusFactory
 import org.mozilla.fenix.mvi.Change
 import org.mozilla.fenix.mvi.Reducer
 import org.mozilla.fenix.mvi.UIComponent
+import org.mozilla.fenix.mvi.UIComponentViewModel
 import org.mozilla.fenix.mvi.ViewState
 
 sealed class SaveCollectionStep {
@@ -51,34 +56,64 @@ sealed class CollectionCreationAction : Action {
 
 class CollectionCreationComponent(
     private val container: ViewGroup,
+    owner: Fragment,
     bus: ActionBusFactory,
     override var initialState: CollectionCreationState = CollectionCreationState()
 ) : UIComponent<CollectionCreationState, CollectionCreationAction, CollectionCreationChange>(
+    owner,
     bus.getManagedEmitter(CollectionCreationAction::class.java),
     bus.getSafeManagedObservable(CollectionCreationChange::class.java)
 ) {
-    override val reducer: Reducer<CollectionCreationState, CollectionCreationChange> =
-        { state, change ->
-            when (change) {
-                is CollectionCreationChange.AddAllTabs -> state.copy(selectedTabs = state.tabs.toSet())
-                is CollectionCreationChange.TabListChange -> state.copy(tabs = change.tabs)
-                is CollectionCreationChange.TabAdded -> {
-                    val selectedTabs = state.selectedTabs + setOf(change.tab)
-                    state.copy(selectedTabs = selectedTabs)
-                }
-                is CollectionCreationChange.TabRemoved -> {
-                    val selectedTabs = state.selectedTabs - setOf(change.tab)
-                    state.copy(selectedTabs = selectedTabs)
-                }
-                is CollectionCreationChange.StepChanged -> {
-                    state.copy(saveCollectionStep = change.saveCollectionStep)
-                }
-            }
-        }
-
     override fun initView() = CollectionCreationUIView(container, actionEmitter, changesObservable)
 
+    override fun render() {
+        ViewModelProvider(owner, CollectionCreationViewModel.Factory(initialState, changesObservable)).get(
+            CollectionCreationViewModel::class.java
+        ).render(uiView)
+    }
+
     init {
-        render(reducer)
+        render()
+    }
+}
+
+class CollectionCreationViewModel(
+    initialState: CollectionCreationState,
+    changesObservable: Observable<CollectionCreationChange>
+) :
+    UIComponentViewModel<CollectionCreationState, CollectionCreationAction, CollectionCreationChange>(
+        initialState,
+        changesObservable,
+        reducer
+    ) {
+
+    class Factory(
+        private val initialState: CollectionCreationState,
+        private val changesObservable: Observable<CollectionCreationChange>
+    ) : ViewModelProvider.Factory {
+        @Suppress("UNCHECKED_CAST")
+        override fun <T : ViewModel?> create(modelClass: Class<T>): T =
+            CollectionCreationViewModel(initialState, changesObservable) as T
+    }
+
+    companion object {
+        val reducer: Reducer<CollectionCreationState, CollectionCreationChange> =
+            { state, change ->
+                when (change) {
+                    is CollectionCreationChange.AddAllTabs -> state.copy(selectedTabs = state.tabs.toSet())
+                    is CollectionCreationChange.TabListChange -> state.copy(tabs = change.tabs)
+                    is CollectionCreationChange.TabAdded -> {
+                        val selectedTabs = state.selectedTabs + setOf(change.tab)
+                        state.copy(selectedTabs = selectedTabs)
+                    }
+                    is CollectionCreationChange.TabRemoved -> {
+                        val selectedTabs = state.selectedTabs - setOf(change.tab)
+                        state.copy(selectedTabs = selectedTabs)
+                    }
+                    is CollectionCreationChange.StepChanged -> {
+                        state.copy(saveCollectionStep = change.saveCollectionStep)
+                    }
+                }
+            }
     }
 }

app/src/main/java/org/mozilla/fenix/collections/CreateCollectionFragment.kt

@@ -50,6 +50,7 @@ class CreateCollectionFragment : DialogFragment() {
 
         collectionCreationComponent = CollectionCreationComponent(
             view.create_collection_wrapper,
+            this,
             ActionBusFactory.get(this),
             CollectionCreationState(
                 tabs = tabs,

app/src/main/java/org/mozilla/fenix/components/toolbar/ToolbarComponent.kt

@@ -7,6 +7,11 @@ package org.mozilla.fenix.components.toolbar
 import android.view.ViewGroup
 import android.widget.ImageView
 import androidx.core.content.ContextCompat
+import androidx.fragment.app.Fragment
+import androidx.lifecycle.ViewModel
+import androidx.lifecycle.ViewModelProvider
+import androidx.lifecycle.ViewModelProviders
+import io.reactivex.Observable
 import kotlinx.android.synthetic.main.component_search.*
 import mozilla.components.browser.search.SearchEngine
 import mozilla.components.browser.toolbar.BrowserToolbar
@@ -17,32 +22,26 @@ import org.mozilla.fenix.mvi.ActionBusFactory
 import org.mozilla.fenix.mvi.Change
 import org.mozilla.fenix.mvi.Reducer
 import org.mozilla.fenix.mvi.UIComponent
+import org.mozilla.fenix.mvi.UIComponentViewModel
 import org.mozilla.fenix.mvi.ViewState
 
 class ToolbarComponent(
     private val container: ViewGroup,
+    owner: Fragment,
     bus: ActionBusFactory,
     private val sessionId: String?,
     private val isPrivate: Boolean,
     override var initialState: SearchState = SearchState("", "", false),
     private val engineIconView: ImageView? = null
 ) :
     UIComponent<SearchState, SearchAction, SearchChange>(
+        owner,
         bus.getManagedEmitter(SearchAction::class.java),
         bus.getSafeManagedObservable(SearchChange::class.java)
     ) {
 
     fun getView(): BrowserToolbar = uiView.toolbar
 
-    override val reducer: Reducer<SearchState, SearchChange> = { state, change ->
-        when (change) {
-            is SearchChange.ToolbarClearedFocus -> state.copy(focused = false)
-            is SearchChange.ToolbarRequestedFocus -> state.copy(focused = true)
-            is SearchChange.SearchShortcutEngineSelected ->
-                state.copy(engine = change.engine)
-        }
-    }
-
     override fun initView() = ToolbarUIView(
         sessionId,
         isPrivate,
@@ -52,8 +51,13 @@ class ToolbarComponent(
         engineIconView
     )
 
+    override fun render() {
+        ViewModelProviders.of(owner, ToolbarViewModel.Factory(initialState, changesObservable))
+            .get(ToolbarViewModel::class.java).render(uiView)
+    }
+
     init {
-        render(reducer)
+        render()
         applyTheme()
     }
 
@@ -95,3 +99,27 @@ sealed class SearchChange : Change {
     object ToolbarClearedFocus : SearchChange()
     data class SearchShortcutEngineSelected(val engine: SearchEngine) : SearchChange()
 }
+
+class ToolbarViewModel(initialState: SearchState, changesObservable: Observable<SearchChange>) :
+    UIComponentViewModel<SearchState, SearchAction, SearchChange>(initialState, changesObservable, reducer) {
+
+    class Factory(
+        private val initialState: SearchState,
+        val changesObservable: Observable<SearchChange>
+    ) : ViewModelProvider.Factory {
+        @Suppress("UNCHECKED_CAST")
+        override fun <T : ViewModel?> create(modelClass: Class<T>): T =
+            ToolbarViewModel(initialState, changesObservable) as T
+    }
+
+    companion object {
+        val reducer: Reducer<SearchState, SearchChange> = { state, change ->
+            when (change) {
+                is SearchChange.ToolbarClearedFocus -> state.copy(focused = false)
+                is SearchChange.ToolbarRequestedFocus -> state.copy(focused = true)
+                is SearchChange.SearchShortcutEngineSelected ->
+                    state.copy(engine = change.engine)
+            }
+        }
+    }
+}

app/src/main/java/org/mozilla/fenix/components/toolbar/ToolbarUIView.kt

@@ -45,7 +45,7 @@ class ToolbarUIView(
     init {
         val sessionManager = view.context.components.core.sessionManager
         val session = sessionId?.let { sessionManager.findSessionById(it) }
-                ?: sessionManager.selectedSession
+            ?: sessionManager.selectedSession
 
         view.apply {
             elevation = resources.pxToDp(TOOLBAR_ELEVATION).toFloat()

app/src/main/java/org/mozilla/fenix/exceptions/ExceptionsComponent.kt

@@ -4,10 +4,16 @@
 package org.mozilla.fenix.exceptions
 
 import android.view.ViewGroup
+import androidx.fragment.app.Fragment
+import androidx.lifecycle.ViewModel
+import androidx.lifecycle.ViewModelProvider
+import androidx.lifecycle.ViewModelProviders
+import io.reactivex.Observable
 import org.mozilla.fenix.mvi.Action
 import org.mozilla.fenix.mvi.ActionBusFactory
 import org.mozilla.fenix.mvi.Change
 import org.mozilla.fenix.mvi.UIComponent
+import org.mozilla.fenix.mvi.UIComponentViewModel
 import org.mozilla.fenix.mvi.ViewState
 import org.mozilla.fenix.test.Mockable
 
@@ -16,24 +22,25 @@ data class ExceptionsItem(val url: String)
 @Mockable
 class ExceptionsComponent(
     private val container: ViewGroup,
+    owner: Fragment,
     bus: ActionBusFactory,
     override var initialState: ExceptionsState = ExceptionsState(emptyList())
 ) :
     UIComponent<ExceptionsState, ExceptionsAction, ExceptionsChange>(
+        owner,
         bus.getManagedEmitter(ExceptionsAction::class.java),
         bus.getSafeManagedObservable(ExceptionsChange::class.java)
     ) {
 
-    override val reducer: (ExceptionsState, ExceptionsChange) -> ExceptionsState = { state, change ->
-        when (change) {
-            is ExceptionsChange.Change -> state.copy(items = change.list)
-        }
+    override fun render() {
+        ViewModelProviders.of(owner, ExceptionsViewModel.Factory(initialState, changesObservable))
+            .get(ExceptionsViewModel::class.java).render(uiView)
     }
 
     override fun initView() = ExceptionsUIView(container, actionEmitter, changesObservable)
 
     init {
-        render(reducer)
+        render()
     }
 }
 
@@ -49,3 +56,28 @@ sealed class ExceptionsAction : Action {
 sealed class ExceptionsChange : Change {
     data class Change(val list: List<ExceptionsItem>) : ExceptionsChange()
 }
+
+class ExceptionsViewModel(initialState: ExceptionsState, changesObservable: Observable<ExceptionsChange>) :
+    UIComponentViewModel<ExceptionsState, ExceptionsAction, ExceptionsChange>(
+        initialState,
+        changesObservable,
+        reducer
+    ) {
+
+    class Factory(
+        private val initialState: ExceptionsState,
+        private val changesObservable: Observable<ExceptionsChange>
+    ) : ViewModelProvider.Factory {
+        @Suppress("UNCHECKED_CAST")
+        override fun <T : ViewModel?> create(modelClass: Class<T>): T =
+            ExceptionsViewModel(initialState, changesObservable) as T
+    }
+
+    companion object {
+        val reducer: (ExceptionsState, ExceptionsChange) -> ExceptionsState = { state, change ->
+            when (change) {
+                is ExceptionsChange.Change -> state.copy(items = change.list)
+            }
+        }
+    }
+}

app/src/main/java/org/mozilla/fenix/exceptions/ExceptionsFragment.kt

@@ -48,6 +48,7 @@ class ExceptionsFragment : Fragment(), CoroutineScope {
         val view = inflater.inflate(R.layout.fragment_exceptions, container, false)
         exceptionsComponent = ExceptionsComponent(
             view.exceptions_layout,
+            this,
             ActionBusFactory.get(this),
             ExceptionsState(loadAndMapExceptions())
         )

app/src/main/java/org/mozilla/fenix/home/HomeFragment.kt

@@ -89,6 +89,7 @@ class HomeFragment : Fragment(), CoroutineScope {
 
         sessionControlComponent = SessionControlComponent(
             view.homeLayout,
+            this,
             bus,
             SessionControlState(listOf(), listOf(), mode)
         )