fix: menu items drag

AnkiDroid/src/main/java/com/ichi2/anki/browser/BrowserColumnSelectionAdapter.kt

@@ -28,7 +28,7 @@ import com.ichi2.anki.browser.BrowserColumnSelectionRecyclerItem.UsageItem
 import com.ichi2.anki.browser.ColumnUsage.AVAILABLE
 import com.ichi2.anki.databinding.ItemBrowserColumnsEntryBinding
 import com.ichi2.anki.databinding.ItemBrowserColumnsHeadingBinding
-import java.util.Collections
+import com.ichi2.anki.utils.ext.swapPositions
 
 class BrowserColumnSelectionAdapter(
     val items: MutableList<BrowserColumnSelectionRecyclerItem>,
@@ -202,7 +202,7 @@ open class BrowserColumnSelectionTouchHelperCallback(
         // `Available` should always be the first element, so don't allow moving above it
         if (toPosition == 0) return false
 
-        Collections.swap(items, fromPosition, toPosition)
+        items.swapPositions(fromPosition, toPosition)
         recyclerView.adapter?.notifyItemMoved(fromPosition, toPosition)
         return true
     }

AnkiDroid/src/main/java/com/ichi2/anki/preferences/reviewer/ReviewerMenuSettingsAdapter.kt

@@ -22,6 +22,7 @@ import androidx.recyclerview.widget.RecyclerView
 import com.ichi2.anki.R
 import com.ichi2.anki.databinding.ItemReviewerMenuBinding
 import com.ichi2.anki.databinding.ItemReviewerMenuDisplayTypeBinding
+import java.util.Objects
 
 /**
  * Provides bindings from menu items and display types (headings) to [RecyclerView] views
@@ -37,8 +38,12 @@ import com.ichi2.anki.databinding.ItemReviewerMenuDisplayTypeBinding
  * @see ReviewerMenuSettingsRecyclerItem
  */
 class ReviewerMenuSettingsAdapter(
-    private val items: List<ReviewerMenuSettingsRecyclerItem>,
+    private val items: MutableList<ReviewerMenuSettingsRecyclerItem>,
 ) : RecyclerView.Adapter<RecyclerView.ViewHolder>() {
+    init {
+        setHasStableIds(true)
+    }
+
     override fun onCreateViewHolder(
         parent: ViewGroup,
         viewType: Int,
@@ -72,6 +77,11 @@ class ReviewerMenuSettingsAdapter(
 
     override fun getItemViewType(position: Int): Int = items[position].viewType
 
+    override fun getItemId(position: Int): Long {
+        val item = items[position]
+        return Objects.hash(item.viewType, item).toLong()
+    }
+
     private var onDragHandleTouchedListener: ((RecyclerView.ViewHolder) -> Unit)? = null
 
     fun setOnDragHandleTouchedListener(listener: (RecyclerView.ViewHolder) -> Unit) {

AnkiDroid/src/main/java/com/ichi2/anki/preferences/reviewer/ReviewerMenuSettingsFragment.kt

@@ -59,7 +59,7 @@ class ReviewerMenuSettingsFragment :
             listOf(ReviewerMenuSettingsRecyclerItem.DisplayType(displayType)) +
                 menuItems.getValue(displayType).map { ReviewerMenuSettingsRecyclerItem.Action(it) }
 
-        val recyclerViewItems = MenuDisplayType.entries.flatMap { section(it) }
+        val recyclerViewItems = MenuDisplayType.entries.flatMap { section(it) }.toMutableList()
 
         val callback = ReviewerMenuSettingsTouchHelperCallback(recyclerViewItems)
         callback.setOnClearViewListener(this)

AnkiDroid/src/main/java/com/ichi2/anki/preferences/reviewer/ReviewerMenuSettingsTouchHelperCallback.kt

@@ -17,7 +17,7 @@ package com.ichi2.anki.preferences.reviewer
 
 import androidx.recyclerview.widget.ItemTouchHelper
 import androidx.recyclerview.widget.RecyclerView
-import java.util.Collections
+import com.ichi2.anki.utils.ext.swapPositions
 
 /**
  * A [ItemTouchHelper.Callback] for the [ReviewerMenuSettingsAdapter].
@@ -29,7 +29,7 @@ import java.util.Collections
  * (see [clearView]).
  */
 class ReviewerMenuSettingsTouchHelperCallback(
-    private val items: List<ReviewerMenuSettingsRecyclerItem>,
+    private val items: MutableList<ReviewerMenuSettingsRecyclerItem>,
 ) : ItemTouchHelper.Callback() {
     private val movementFlags = makeMovementFlags(ItemTouchHelper.UP or ItemTouchHelper.DOWN, 0)
 
@@ -54,7 +54,7 @@ class ReviewerMenuSettingsTouchHelperCallback(
         // `Always show` should always be the first element, so don't allow moving above it
         if (toPosition == 0) return false
 
-        Collections.swap(items, fromPosition, toPosition)
+        items.swapPositions(fromPosition, toPosition)
         recyclerView.adapter?.notifyItemMoved(fromPosition, toPosition)
         return true
     }

AnkiDroid/src/main/java/com/ichi2/anki/utils/ext/MutableList.kt

@@ -0,0 +1,24 @@
+// SPDX-FileCopyrightText: 2026 Brayan Oliveira <brayandso.dev@gmail.com>
+// SPDX-License-Identifier: GPL-3.0-or-later
+package com.ichi2.anki.utils.ext
+
+import java.util.Collections
+
+/**
+ * Moves an item within a MutableList by swapping adjacent elements. This is particularly
+ * optimized for [androidx.recyclerview.widget.ItemTouchHelper] drag-and-drop operations.
+ */
+fun <T> MutableList<T>.swapPositions(
+    fromPosition: Int,
+    toPosition: Int,
+) {
+    if (fromPosition < toPosition) {
+        for (i in fromPosition until toPosition) {
+            Collections.swap(this, i, i + 1)
+        }
+    } else {
+        for (i in fromPosition downTo toPosition + 1) {
+            Collections.swap(this, i, i - 1)
+        }
+    }
+}