Fix alpha resetting for the TrackerAnimationTile

The previous commit fixed issues with drag and drop of tabs and glitches. Unfortunately it meant that the alpha state of the TrackerAnimationTile seemed to change as well, this seems to be due to the TabSwitcherItemDiffCallback being called and then triggering changes.

Now we pass through the isDragging state to the diff callback so that we can ensure that if we update the list that we maintain the TrackerAnimationTile alpha state, otherwise it would just reset to default.

app/src/main/java/com/duckduckgo/app/browser/tabs/adapter/TabSwitcherItemDiffCallback.kt

@@ -19,8 +19,14 @@ package com.duckduckgo.app.browser.tabs.adapter
 import android.os.Bundle
 import androidx.recyclerview.widget.DiffUtil
 import com.duckduckgo.app.tabs.ui.TabSwitcherItem
+import com.duckduckgo.app.tabs.ui.TabSwitcherItem.TrackerAnimationTile.ANIMATED_TILE_DEFAULT_ALPHA
+import com.duckduckgo.app.tabs.ui.TabSwitcherItem.TrackerAnimationTile.ANIMATED_TILE_NO_REPLACE_ALPHA
 
-class TabSwitcherItemDiffCallback(old: List<TabSwitcherItem>, new: List<TabSwitcherItem>) : DiffUtil.Callback() {
+class TabSwitcherItemDiffCallback(
+    old: List<TabSwitcherItem>,
+    new: List<TabSwitcherItem>,
+    private val isDragging: Boolean,
+) : DiffUtil.Callback() {
 
     // keep a local copy of the lists to avoid any changes to the lists during the diffing process
     private val oldList = old.toList()
@@ -72,6 +78,12 @@ class TabSwitcherItemDiffCallback(old: List<TabSwitcherItem>, new: List<TabSwitc
                     diffBundle.putString(DIFF_KEY_PREVIEW, newItem.tabEntity.tabPreviewFile)
                 }
             }
+            oldItem is TabSwitcherItem.TrackerAnimationTile && newItem is TabSwitcherItem.TrackerAnimationTile -> {
+                diffBundle.putFloat(
+                    DIFF_ALPHA,
+                    if (isDragging) ANIMATED_TILE_NO_REPLACE_ALPHA else ANIMATED_TILE_DEFAULT_ALPHA,
+                )
+            }
         }
 
         return diffBundle
@@ -114,5 +126,6 @@ class TabSwitcherItemDiffCallback(old: List<TabSwitcherItem>, new: List<TabSwitc
         const val DIFF_KEY_URL = "url"
         const val DIFF_KEY_PREVIEW = "previewImage"
         const val DIFF_KEY_VIEWED = "viewed"
+        const val DIFF_ALPHA = "alpha"
     }
 }

app/src/main/java/com/duckduckgo/app/tabs/ui/TabSwitcherAdapter.kt

@@ -42,6 +42,7 @@ import com.duckduckgo.app.browser.databinding.ItemTabListBinding
 import com.duckduckgo.app.browser.favicon.FaviconManager
 import com.duckduckgo.app.browser.tabpreview.WebViewPreviewPersister
 import com.duckduckgo.app.browser.tabs.adapter.TabSwitcherItemDiffCallback
+import com.duckduckgo.app.browser.tabs.adapter.TabSwitcherItemDiffCallback.Companion.DIFF_ALPHA
 import com.duckduckgo.app.browser.tabs.adapter.TabSwitcherItemDiffCallback.Companion.DIFF_KEY_PREVIEW
 import com.duckduckgo.app.browser.tabs.adapter.TabSwitcherItemDiffCallback.Companion.DIFF_KEY_TITLE
 import com.duckduckgo.app.browser.tabs.adapter.TabSwitcherItemDiffCallback.Companion.DIFF_KEY_URL
@@ -53,6 +54,8 @@ import com.duckduckgo.app.tabs.ui.TabSwitcherAdapter.TabSwitcherViewHolder.Compa
 import com.duckduckgo.app.tabs.ui.TabSwitcherAdapter.TabSwitcherViewHolder.Companion.LIST_TAB
 import com.duckduckgo.app.tabs.ui.TabSwitcherAdapter.TabSwitcherViewHolder.Companion.LIST_TRACKER_ANIMATION_TILE
 import com.duckduckgo.app.tabs.ui.TabSwitcherAdapter.TabSwitcherViewHolder.TabViewHolder
+import com.duckduckgo.app.tabs.ui.TabSwitcherItem.TrackerAnimationTile.ANIMATED_TILE_DEFAULT_ALPHA
+import com.duckduckgo.app.tabs.ui.TabSwitcherItem.TrackerAnimationTile.ANIMATED_TILE_NO_REPLACE_ALPHA
 import com.duckduckgo.common.ui.view.show
 import com.duckduckgo.common.utils.DispatcherProvider
 import com.duckduckgo.common.utils.swap
@@ -63,10 +66,6 @@ import kotlinx.coroutines.launch
 import kotlinx.coroutines.withContext
 import timber.log.Timber
 
-private const val ANIMATED_TILE_NO_REPLACE_ALPHA = 0.4f
-private const val ANIMATED_TILE_DEFAULT_ALPHA = 1f
-private const val ALPHA = "alpha"
-
 class TabSwitcherAdapter(
     private val itemClickListener: TabSwitcherListener,
     private val webViewPreviewPersister: WebViewPreviewPersister,
@@ -242,7 +241,7 @@ class TabSwitcherAdapter(
             GRID_TRACKER_ANIMATION_TILE, LIST_TRACKER_ANIMATION_TILE -> {
                 for (payload in payloads) {
                     val bundle = payload as Bundle
-                    holder.itemView.alpha = bundle.getFloat("alpha", ANIMATED_TILE_DEFAULT_ALPHA)
+                    holder.itemView.alpha = bundle.getFloat(DIFF_ALPHA, ANIMATED_TILE_DEFAULT_ALPHA)
                 }
             }
         }
@@ -342,7 +341,7 @@ class TabSwitcherAdapter(
     }
 
     fun updateData(updatedList: List<TabSwitcherItem>) {
-        val diffResult = DiffUtil.calculateDiff(TabSwitcherItemDiffCallback(list, updatedList))
+        val diffResult = DiffUtil.calculateDiff(TabSwitcherItemDiffCallback(list, updatedList, isDragging))
         list.clear()
         list.addAll(updatedList)
         diffResult.dispatchUpdatesTo(this)
@@ -370,7 +369,7 @@ class TabSwitcherAdapter(
             notifyItemChanged(
                 animatedTilePosition,
                 Bundle().apply {
-                    putFloat(ALPHA, alpha)
+                    putFloat(DIFF_ALPHA, alpha)
                 },
             )
         }

app/src/main/java/com/duckduckgo/app/tabs/ui/TabSwitcherItem.kt

@@ -21,5 +21,9 @@ import com.duckduckgo.app.tabs.model.TabEntity
 sealed class TabSwitcherItem(val id: String) {
 
     data class Tab(val tabEntity: TabEntity) : TabSwitcherItem(tabEntity.tabId)
-    data object TrackerAnimationTile : TabSwitcherItem("TrackerAnimationTile")
+    data object TrackerAnimationTile : TabSwitcherItem("TrackerAnimationTile") {
+
+        const val ANIMATED_TILE_NO_REPLACE_ALPHA = 0.4f
+        const val ANIMATED_TILE_DEFAULT_ALPHA = 1f
+    }
 }