Fix crash when clicking retry button in favorites

app/src/main/kotlin/com/hippo/ehviewer/ui/scene/FavoritesScene.kt

@@ -360,7 +360,7 @@ class FavoritesScene : SearchBarScene() {
                     "favorite-selection",
                     this,
                     { adapter.snapshot().items },
-                    { (this as GalleryHolder).galleryId },
+                    { (this as? GalleryHolder)?.galleryId },
                 ).apply {
                     addCustomChoiceListener({
                         showSelectionFab()

app/src/main/kotlin/com/hippo/ehviewer/ui/scene/GallerySelectionTracker.kt

@@ -2,10 +2,13 @@ package com.hippo.ehviewer.ui.scene
 
 import android.os.Bundle
 import android.view.MotionEvent
+import androidx.core.util.component1
+import androidx.core.util.component2
 import androidx.recyclerview.selection.ItemDetailsLookup
 import androidx.recyclerview.selection.ItemKeyProvider
 import androidx.recyclerview.selection.SelectionTracker
 import androidx.recyclerview.selection.StorageStrategy
+import androidx.recyclerview.widget.ConcatAdapter
 import androidx.recyclerview.widget.RecyclerView
 import com.hippo.ehviewer.client.data.GalleryInfo
 
@@ -13,37 +16,48 @@ class GallerySelectionTracker<T : GalleryInfo>(
     selectionId: String,
     recyclerView: RecyclerView,
     private val getItems: () -> List<T>,
-    getItemKey: RecyclerView.ViewHolder.() -> Long,
+    getItemKey: RecyclerView.ViewHolder.() -> Long?,
     builder: SelectionTracker.Builder<Long>.() -> Unit = {},
 ) {
-    private val tracker: SelectionTracker<Long>
+    private val adapter = recyclerView.adapter as? ConcatAdapter
+    private val tracker = SelectionTracker.Builder(
+        selectionId,
+        recyclerView,
+        object : ItemKeyProvider<Long>(SCOPE_MAPPED) {
+            override fun getKey(position: Int) =
+                if (adapter != null) {
+                    val (wrappedAdapter, localPosition) = adapter.getWrappedAdapterAndPosition(position)
+                    (wrappedAdapter as? GalleryAdapter)?.let {
+                        getItems()[localPosition].gid
+                    }
+                } else {
+                    getItems()[position].gid
+                }
+
+            override fun getPosition(key: Long) =
+                if (adapter != null) {
+                    adapter.adapters[0].itemCount
+                } else {
+                    0
+                } + getItems().indexOfFirst { it.gid == key }
+        },
+        object : ItemDetailsLookup<Long>() {
+            override fun getItemDetails(e: MotionEvent) =
+                recyclerView.findChildViewUnder(e.x, e.y)?.let {
+                    recyclerView.getChildViewHolder(it).run {
+                        object : ItemDetails<Long>() {
+                            override fun getPosition() = absoluteAdapterPosition
+                            override fun getSelectionKey() = getItemKey()
+                        }
+                    }
+                }
+        },
+        StorageStrategy.createLongStorage(),
+    ).apply(builder).build()
     val selectionSize get() = tracker.selection.size()
     var isInCustomChoice = false
         private set
 
-    init {
-        tracker = SelectionTracker.Builder(
-            selectionId,
-            recyclerView,
-            object : ItemKeyProvider<Long>(SCOPE_MAPPED) {
-                override fun getKey(position: Int) = getItems()[position].gid
-                override fun getPosition(key: Long) = getItems().indexOfFirst { it.gid == key }
-            },
-            object : ItemDetailsLookup<Long>() {
-                override fun getItemDetails(e: MotionEvent) =
-                    recyclerView.findChildViewUnder(e.x, e.y)?.let {
-                        recyclerView.getChildViewHolder(it).run {
-                            object : ItemDetails<Long>() {
-                                override fun getPosition() = bindingAdapterPosition
-                                override fun getSelectionKey() = getItemKey()
-                            }
-                        }
-                    }
-            },
-            StorageStrategy.createLongStorage(),
-        ).apply(builder).build()
-    }
-
     fun addCustomChoiceListener(onIntoCustomChoiceListener: () -> Unit, onOutOfCustomChoiceListener: () -> Unit) {
         tracker.addObserver(object : SelectionTracker.SelectionObserver<Long>() {
             override fun onSelectionChanged() {