[fenix] Close https://github.com/mozilla-mobile/fenix/issues/18443: Use recyclerview-selection for multi-select mode in tray

Add multi-select mode to the BrowserTabsAdapter. It has the
functionality to:
 - Enable multi-select mode on long-press.
 - Enable multi-select mode when changed by an external function.
 - Only works for normal tabs (as we currently have it).

Co-authored-by: "codrut.topliceanu" <codrut.topliceanu@softvision.ro>

app/build.gradle

@@ -533,6 +533,7 @@ dependencies {
     implementation Deps.androidx_navigation_fragment
     implementation Deps.androidx_navigation_ui
     implementation Deps.androidx_recyclerview
+    implementation Deps.androidx_recyclerview_selection
     implementation Deps.androidx_lifecycle_livedata
     implementation Deps.androidx_lifecycle_runtime
     implementation Deps.androidx_lifecycle_viewmodel

app/src/main/java/org/mozilla/fenix/tabstray/TrayPagerAdapter.kt

@@ -9,8 +9,6 @@ import android.view.LayoutInflater
 import android.view.ViewGroup
 import androidx.recyclerview.widget.GridLayoutManager
 import androidx.recyclerview.widget.RecyclerView
-import org.mozilla.fenix.tabstray.BrowserTabViewHolder.Companion.LAYOUT_ID_NORMAL_TAB
-import org.mozilla.fenix.tabstray.BrowserTabViewHolder.Companion.LAYOUT_ID_PRIVATE_TAB
 import org.mozilla.fenix.tabstray.browser.BrowserTabsAdapter
 import org.mozilla.fenix.tabstray.browser.BrowserTrayInteractor
 
@@ -27,8 +25,14 @@ class TrayPagerAdapter(
         val itemView = LayoutInflater.from(parent.context).inflate(viewType, parent, false)
 
         return when (viewType) {
-            LAYOUT_ID_NORMAL_TAB -> BrowserTabViewHolder(itemView, interactor)
+            NormalBrowserTabViewHolder.LAYOUT_ID -> NormalBrowserTabViewHolder(
-            LAYOUT_ID_PRIVATE_TAB -> BrowserTabViewHolder(itemView, interactor)
+                itemView,
+                interactor
+            )
+            PrivateBrowserTabViewHolder.LAYOUT_ID -> PrivateBrowserTabViewHolder(
+                itemView,
+                interactor
+            )
             else -> throw IllegalStateException("Unknown viewType.")
         }
     }
@@ -45,8 +49,8 @@ class TrayPagerAdapter(
 
     override fun getItemViewType(position: Int): Int {
         return when (position) {
-            POSITION_NORMAL_TABS -> LAYOUT_ID_NORMAL_TAB
+            POSITION_NORMAL_TABS -> NormalBrowserTabViewHolder.LAYOUT_ID
-            POSITION_PRIVATE_TABS -> LAYOUT_ID_PRIVATE_TAB
+            POSITION_PRIVATE_TABS -> PrivateBrowserTabViewHolder.LAYOUT_ID
             else -> throw IllegalStateException("Unknown position.")
         }
     }

app/src/main/java/org/mozilla/fenix/tabstray/TrayViewHolders.kt

@@ -5,15 +5,22 @@
 package org.mozilla.fenix.tabstray
 
 import android.view.View
+import androidx.annotation.CallSuper
+import androidx.recyclerview.selection.SelectionPredicates
+import androidx.recyclerview.selection.SelectionTracker
+import androidx.recyclerview.selection.StableIdKeyProvider
+import androidx.recyclerview.selection.StorageStrategy
 import androidx.recyclerview.widget.RecyclerView
 import kotlinx.android.extensions.LayoutContainer
 import org.mozilla.fenix.R
 import org.mozilla.fenix.tabstray.browser.BaseBrowserTrayList
+import org.mozilla.fenix.tabstray.browser.BrowserTabsAdapter
+import org.mozilla.fenix.tabstray.browser.TabsDetailsLookup
 
 /**
  * Base [RecyclerView.ViewHolder] for [TrayPagerAdapter] items.
  */
-sealed class TrayViewHolder constructor(
+abstract class TrayViewHolder constructor(
     override val containerView: View
 ) : RecyclerView.ViewHolder(containerView), LayoutContainer {
 
@@ -23,17 +30,18 @@ sealed class TrayViewHolder constructor(
     )
 }
 
-class BrowserTabViewHolder(
+abstract class BrowserTabViewHolder(
     containerView: View,
     interactor: TabsTrayInteractor
 ) : TrayViewHolder(containerView) {
 
-    private val trayList: BaseBrowserTrayList = itemView.findViewById(R.id.tray_list_item)
+    protected val trayList: BaseBrowserTrayList = itemView.findViewById(R.id.tray_list_item)
 
     init {
         trayList.interactor = interactor
     }
 
+    @CallSuper
     override fun bind(
         adapter: RecyclerView.Adapter<out RecyclerView.ViewHolder>,
         layoutManager: RecyclerView.LayoutManager
@@ -41,9 +49,50 @@ class BrowserTabViewHolder(
         trayList.layoutManager = layoutManager
         trayList.adapter = adapter
     }
+}
+
+class NormalBrowserTabViewHolder(
+    containerView: View,
+    interactor: TabsTrayInteractor
+) : BrowserTabViewHolder(containerView, interactor) {
+
+    private lateinit var selectionTracker: SelectionTracker<Long>
+
+    override fun bind(
+        adapter: RecyclerView.Adapter<out RecyclerView.ViewHolder>,
+        layoutManager: RecyclerView.LayoutManager
+    ) {
+        super.bind(adapter, layoutManager)
+
+        selectionTracker = SelectionTracker.Builder(
+            "mySelection",
+            trayList,
+            StableIdKeyProvider(trayList),
+            TabsDetailsLookup(trayList),
+            StorageStrategy.createLongStorage()
+        ).withSelectionPredicate(
+            SelectionPredicates.createSelectAnything()
+        ).build()
+
+        (adapter as BrowserTabsAdapter).tracker = selectionTracker
+
+        selectionTracker.addObserver(object : SelectionTracker.SelectionObserver<Long>() {
+            override fun onItemStateChanged(key: Long, selected: Boolean) {
+                // TODO Do nothing for now; remove in a future patch if needed.
+            }
+        })
+    }
 
     companion object {
-        const val LAYOUT_ID_NORMAL_TAB = R.layout.normal_browser_tray_list
+        const val LAYOUT_ID = R.layout.normal_browser_tray_list
-        const val LAYOUT_ID_PRIVATE_TAB = R.layout.private_browser_tray_list
+    }
+}
+
+class PrivateBrowserTabViewHolder(
+    containerView: View,
+    interactor: TabsTrayInteractor
+) : BrowserTabViewHolder(containerView, interactor) {
+    companion object {
+        const val LAYOUT_ID = R.layout.private_browser_tray_list
     }
 }

app/src/main/java/org/mozilla/fenix/tabstray/browser/BaseBrowserTrayList.kt

@@ -53,7 +53,7 @@ abstract class BaseBrowserTrayList @JvmOverloads constructor(
     private val tabsFeature by lazy {
         ViewBoundFeatureWrapper(
             feature = TabsFeature(
-                adapter as TabsAdapter,
+                adapter as BrowserTabsAdapter,
                 context.components.core.store,
                 selectTabUseCase,
                 removeTabUseCase,

app/src/main/java/org/mozilla/fenix/tabstray/browser/BrowserTabsAdapter.kt

@@ -6,6 +6,7 @@ package org.mozilla.fenix.tabstray.browser
 
 import android.content.Context
 import android.view.ViewGroup
+import androidx.recyclerview.selection.SelectionTracker
 import androidx.recyclerview.widget.RecyclerView
 import androidx.recyclerview.widget.GridLayoutManager
 import kotlinx.android.synthetic.main.tab_tray_item.view.*
@@ -27,7 +28,7 @@ class BrowserTabsAdapter(
     private val interactor: BrowserTrayInteractor,
     private val layoutManager: (() -> GridLayoutManager)? = null,
     delegate: Observable<TabsTray.Observer> = ObserverRegistry()
-) : TabsAdapter(delegate) {
+) : TabsAdapter<TabViewHolder>(delegate) {
 
     /**
      * The layout types for the tabs.
@@ -37,8 +38,17 @@ class BrowserTabsAdapter(
         GRID
     }
 
+    /**
+     * Tracks the selected tabs in multi-select mode.
+     */
+    var tracker: SelectionTracker<Long>? = null
+
     private val imageLoader = ThumbnailLoader(context.components.core.thumbnailStorage)
 
+    init {
+        setHasStableIds(true)
+    }
+
     override fun getItemViewType(position: Int): Int {
         return if (context.settings().gridTabView) {
             ViewType.GRID.ordinal
@@ -54,19 +64,12 @@ class BrowserTabsAdapter(
         }
     }
 
+    override fun getItemId(position: Int) = position.toLong()
+
     override fun onBindViewHolder(holder: TabViewHolder, position: Int) {
         super.onBindViewHolder(holder, position)
 
         holder.tab?.let { tab ->
-            if (!tab.private) {
-                holder.itemView.setOnLongClickListener {
-                    interactor.onMultiSelect(true)
-                    true
-                }
-            } else {
-                holder.itemView.setOnLongClickListener(null)
-            }
-
             holder.itemView.setOnClickListener {
                 interactor.onOpenTab(tab)
             }
@@ -74,6 +77,10 @@ class BrowserTabsAdapter(
             holder.itemView.mozac_browser_tabstray_close.setOnClickListener {
                 interactor.onCloseTab(tab)
             }
+
+            tracker?.let {
+                holder.showTabIsMultiSelectEnabled(it.isSelected(position.toLong()))
+            }
         }
     }
 }

app/src/main/java/org/mozilla/fenix/tabstray/browser/BrowserTrayInteractor.kt

@@ -9,7 +9,8 @@ import mozilla.components.feature.tabs.TabsUseCases
 import org.mozilla.fenix.tabstray.TabsTrayInteractor
 
 /**
- * For interacting with UI that extends from [BaseBrowserTrayList] and other browser tab tray views.
+ * For interacting with UI that is specifically for [BaseBrowserTrayList] and other browser
+ * tab tray views.
  */
 interface BrowserTrayInteractor {
 
@@ -24,9 +25,9 @@ interface BrowserTrayInteractor {
     fun onCloseTab(tab: Tab)
 
     /**
-     * Enable or disable multi-select mode.
+     * If multi-select mode is enabled or disabled.
      */
-    fun onMultiSelect(enabled: Boolean)
+    fun isMultiSelectMode(): Boolean
 }
 
 /**
@@ -54,9 +55,10 @@ class DefaultBrowserTrayInteractor(
     }
 
     /**
-     * See [BrowserTrayInteractor.onMultiSelect].
+     * See [BrowserTrayInteractor.isMultiSelectMode].
      */
-    override fun onMultiSelect(enabled: Boolean) {
+    override fun isMultiSelectMode(): Boolean {
-        // TODO https://github.com/mozilla-mobile/fenix/issues/18443
+        // Needs https://github.com/mozilla-mobile/fenix/issues/18513 to change this value
+        return false
     }
 }

app/src/main/java/org/mozilla/fenix/tabstray/browser/TabsAdapter.kt

@@ -18,14 +18,12 @@ import mozilla.components.support.base.observer.ObserverRegistry
 // for Android UI APIs.
 //
 // TODO Let's upstream this to AC with tests.
-abstract class TabsAdapter(
+abstract class TabsAdapter<T : TabViewHolder>(
     delegate: Observable<TabsTray.Observer> = ObserverRegistry()
-) : RecyclerView.Adapter<TabViewHolder>(), TabsTray, Observable<TabsTray.Observer> by delegate {
+) : RecyclerView.Adapter<T>(), TabsTray, Observable<TabsTray.Observer> by delegate {
-    private var tabs: Tabs? = null
 
-    var styling: TabsTrayStyling = TabsTrayStyling()
+    protected var tabs: Tabs? = null
-
+    protected var styling: TabsTrayStyling = TabsTrayStyling()
-    override fun getItemCount(): Int = tabs?.list?.size ?: 0
 
     @CallSuper
     override fun updateTabs(tabs: Tabs) {
@@ -35,12 +33,14 @@ abstract class TabsAdapter(
     }
 
     @CallSuper
-    override fun onBindViewHolder(holder: TabViewHolder, position: Int) {
+    override fun onBindViewHolder(holder: T, position: Int) {
         val tabs = tabs ?: return
 
         holder.bind(tabs.list[position], isTabSelected(tabs, position), styling, this)
     }
 
+    override fun getItemCount(): Int = tabs?.list?.size ?: 0
+
     final override fun isTabSelected(tabs: Tabs, position: Int): Boolean =
         tabs.selectedIndex == position
 

app/src/main/java/org/mozilla/fenix/tabstray/browser/TabsDetailsLookup.kt

@@ -0,0 +1,28 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.fenix.tabstray.browser
+
+import android.view.MotionEvent
+import androidx.recyclerview.selection.ItemDetailsLookup
+import androidx.recyclerview.selection.ItemDetailsLookup.ItemDetails
+import androidx.recyclerview.widget.RecyclerView
+import org.mozilla.fenix.tabtray.TabTrayViewHolder
+
+/**
+ * An [ItemDetailsLookup] for retrieving the [ItemDetails] of a [TabTrayViewHolder].
+ */
+class TabsDetailsLookup(
+    private val recyclerView: RecyclerView
+) : ItemDetailsLookup<Long>() {
+
+    override fun getItemDetails(event: MotionEvent): ItemDetails<Long>? {
+        val view = recyclerView.findChildViewUnder(event.x, event.y)
+        if (view != null) {
+            val viewHolder = recyclerView.getChildViewHolder(view) as TabTrayViewHolder
+            return viewHolder.getItemDetails()
+        }
+        return null
+    }
+}

app/src/main/java/org/mozilla/fenix/tabtray/TabTrayViewHolder.kt

@@ -4,6 +4,7 @@
 
 package org.mozilla.fenix.tabtray
 
+import android.view.MotionEvent
 import android.view.View
 import android.widget.ImageButton
 import android.widget.ImageView
@@ -12,7 +13,12 @@ import androidx.annotation.VisibleForTesting
 import androidx.appcompat.content.res.AppCompatResources
 import androidx.appcompat.widget.AppCompatImageButton
 import androidx.core.content.ContextCompat
+import androidx.core.view.isVisible
+import androidx.recyclerview.selection.ItemDetailsLookup
+import kotlinx.android.synthetic.main.checkbox_item.view.*
 import kotlinx.android.synthetic.main.tab_tray_grid_item.view.*
+import kotlinx.android.synthetic.main.tab_tray_grid_item.view.mozac_browser_tabstray_close
+import kotlinx.android.synthetic.main.tab_tray_item.view.*
 import mozilla.components.browser.state.selector.findTabOrCustomTab
 import mozilla.components.browser.state.store.BrowserStore
 import mozilla.components.browser.tabstray.TabViewHolder
@@ -35,6 +41,7 @@ import org.mozilla.fenix.ext.removeTouchDelegate
 import org.mozilla.fenix.ext.settings
 import org.mozilla.fenix.ext.showAndEnable
 import org.mozilla.fenix.ext.toShortUrl
+import org.mozilla.fenix.tabstray.browser.BrowserTrayInteractor
 import kotlin.math.max
 
 /**
@@ -44,7 +51,8 @@ class TabTrayViewHolder(
     itemView: View,
     private val imageLoader: ImageLoader,
     private val store: BrowserStore = itemView.context.components.core.store,
-    private val metrics: MetricController = itemView.context.components.analytics.metrics
+    private val metrics: MetricController = itemView.context.components.analytics.metrics,
+    private val browserTrayInteractor: BrowserTrayInteractor? = null
 ) : TabViewHolder(itemView) {
 
     private val faviconView: ImageView? =
@@ -196,6 +204,20 @@ class TabTrayViewHolder(
         )
     }
 
+    fun getItemDetails() = object : ItemDetailsLookup.ItemDetails<Long>() {
+        override fun getPosition(): Int = bindingAdapterPosition
+        override fun getSelectionKey(): Long = itemId
+        override fun inSelectionHotspot(e: MotionEvent): Boolean {
+            return browserTrayInteractor?.isMultiSelectMode() == true
+        }
+    }
+
+    fun showTabIsMultiSelectEnabled(isSelected: Boolean) {
+        itemView.selected_mask.isVisible = isSelected
+        itemView.mozac_browser_tabstray_close.isVisible =
+            browserTrayInteractor?.isMultiSelectMode() == false
+    }
+
     private fun updateCloseButtonDescription(title: String) {
         closeView.contentDescription =
             closeView.context.getString(R.string.close_tab_title, title)

buildSrc/src/main/java/Dependencies.kt

@@ -29,6 +29,7 @@ object Versions {
     const val androidx_fragment = "1.2.5"
     const val androidx_navigation = "2.3.3"
     const val androidx_recyclerview = "1.2.0-beta01"
+    const val androidx_recyclerview_selection = "1.0.0"
     const val androidx_core = "1.3.2"
     const val androidx_paging = "2.1.2"
     const val androidx_transition = "1.4.0"
@@ -185,6 +186,7 @@ object Deps {
     const val androidx_navigation_fragment = "androidx.navigation:navigation-fragment-ktx:${Versions.androidx_navigation}"
     const val androidx_navigation_ui = "androidx.navigation:navigation-ui:${Versions.androidx_navigation}"
     const val androidx_recyclerview = "androidx.recyclerview:recyclerview:${Versions.androidx_recyclerview}"
+    const val androidx_recyclerview_selection = "androidx.recyclerview:recyclerview-selection:${Versions.androidx_recyclerview_selection}"
     const val androidx_core = "androidx.core:core:${Versions.androidx_core}"
     const val androidx_core_ktx = "androidx.core:core-ktx:${Versions.androidx_core}"
     const val androidx_transition = "androidx.transition:transition:${Versions.androidx_transition}"