detail: diff instead of replace when resorting

Completely rework the detail list implementations so that resorting the
song list causes a replace operation instead of a diff operation.

This finally makes the list experience consistent across the app.

CHANGELOG.md

@@ -4,7 +4,7 @@
 
 #### What's New
 - Added ability to play/shuffle selections
-- Visually refreshed header components
+- Resigned header components
 - Resigned settings view
 
 #### What's Improved
@@ -13,6 +13,7 @@
 - Pressing the button will now clear the current selection before navigating back
 - Added support for non-standard `ARTISTS` tags
 - Play Next and Add To Queue now start playback if there is no queue to add
+- Made resorting list animations consistent across app
 
 #### What's Fixed
 - Fixed unreliable ReplayGain adjustment application in certain situations
@@ -20,6 +21,8 @@
 file manager
 - Fixed notification not updating due to settings changes
 - Fixed genre picker from repeatedly showing up when device rotates
+- Fixed multi-value genres not being recognized on vorbis files
+- Fixed sharp-cornered widget bar appearing even when round mode was enabled
 
 #### What's Changed
 - Implemented new queue system

app/src/main/java/com/google/android/material/bottomsheet/BackportBottomSheetBehavior.java

@@ -83,7 +83,7 @@ import java.util.Map;
  * window-like. For BottomSheetDialog use {@link BottomSheetDialog#setTitle(int)}, and for
  * BottomSheetDialogFragment use {@link ViewCompat#setAccessibilityPaneTitle(View, CharSequence)}.
  *
- * Modified at several points by Alexander Capehart backport miscellaneous fixes not currently
+ * Modified at several points by Alexander Capehart to backport miscellaneous fixes not currently
  * obtainable in the currently used MDC library.
  */
 public class BackportBottomSheetBehavior<V extends View> extends CoordinatorLayout.Behavior<V> {

app/src/main/java/com/google/android/material/divider/BackportMaterialDividerItemDecoration.java

@@ -53,6 +53,9 @@ import com.google.android.material.resources.MaterialResources;
  *             layoutManager.getOrientation());
  *     recyclerView.addItemDecoration(dividerItemDecoration);
  * </pre>
+ *
+ * Modified at several points by Alexander Capehart to backport miscellaneous fixes not currently
+ * obtainable in the currently used MDC library.
  */
 public class BackportMaterialDividerItemDecoration extends ItemDecoration {
   public static final int HORIZONTAL = LinearLayout.HORIZONTAL;

app/src/main/java/org/oxycblt/auxio/detail/AlbumDetailFragment.kt

@@ -31,7 +31,6 @@ import org.oxycblt.auxio.databinding.FragmentDetailBinding
 import org.oxycblt.auxio.detail.recycler.AlbumDetailAdapter
 import org.oxycblt.auxio.list.Item
 import org.oxycblt.auxio.list.ListFragment
-import org.oxycblt.auxio.list.recycler.BasicInstructions
 import org.oxycblt.auxio.music.Album
 import org.oxycblt.auxio.music.Artist
 import org.oxycblt.auxio.music.Music
@@ -141,12 +140,12 @@ class AlbumDetailFragment :
 
     override fun onOpenSortMenu(anchor: View) {
         openMenu(anchor, R.menu.menu_album_sort) {
-            val sort = detailModel.albumSortSort
+            val sort = detailModel.albumSongSort
             unlikelyToBeNull(menu.findItem(sort.mode.itemId)).isChecked = true
             unlikelyToBeNull(menu.findItem(R.id.option_sort_asc)).isChecked = sort.isAscending
             setOnMenuItemClickListener { item ->
                 item.isChecked = !item.isChecked
-                detailModel.albumSortSort =
+                detailModel.albumSongSort =
                     if (item.itemId == R.id.option_sort_asc) {
                         sort.withAscending(item.isChecked)
                     } else {
@@ -260,7 +259,9 @@ class AlbumDetailFragment :
     }
 
     private fun updateList(items: List<Item>) {
-        detailAdapter.submitList(items, BasicInstructions.DIFF)
+        detailAdapter.submitList(
+            items, detailModel.albumListInstructions ?: DetailListInstructions.Diff)
+        detailModel.finishAlbumListInstructions()
     }
 
     private fun updateSelection(selected: List<Music>) {

app/src/main/java/org/oxycblt/auxio/detail/ArtistDetailFragment.kt

@@ -31,7 +31,6 @@ import org.oxycblt.auxio.detail.recycler.ArtistDetailAdapter
 import org.oxycblt.auxio.detail.recycler.DetailAdapter
 import org.oxycblt.auxio.list.Item
 import org.oxycblt.auxio.list.ListFragment
-import org.oxycblt.auxio.list.recycler.BasicInstructions
 import org.oxycblt.auxio.music.Album
 import org.oxycblt.auxio.music.Artist
 import org.oxycblt.auxio.music.Music
@@ -236,7 +235,9 @@ class ArtistDetailFragment :
     }
 
     private fun updateList(items: List<Item>) {
-        detailAdapter.submitList(items, BasicInstructions.DIFF)
+        detailAdapter.submitList(
+            items, detailModel.artistListInstructions ?: DetailListInstructions.Diff)
+        detailModel.finishArtistListInstructions()
     }
 
     private fun updateSelection(selected: List<Music>) {

app/src/main/java/org/oxycblt/auxio/detail/Detail.kt

@@ -25,12 +25,14 @@ import org.oxycblt.auxio.music.storage.MimeType
 /**
  * A header variation that displays a button to open a sort menu.
  * @param titleRes The string resource to use as the header title
+ * @author Alexander Capehart (OxygenCobalt)
  */
 data class SortHeader(@StringRes val titleRes: Int) : Item
 
 /**
  * A header variation that delimits between disc groups.
  * @param disc The disc number to be displayed on the header.
+ * @author Alexander Capehart (OxygenCobalt)
  */
 data class DiscHeader(val disc: Int) : Item
 
@@ -39,9 +41,25 @@ data class DiscHeader(val disc: Int) : Item
  * @param bitrateKbps The bit rate, in kilobytes-per-second. Null if it could not be parsed.
  * @param sampleRateHz The sample rate, in hertz.
  * @param resolvedMimeType The known mime type of the [Song] after it's file format was determined.
+ * @author Alexander Capehart (OxygenCobalt)
  */
 data class SongProperties(
     val bitrateKbps: Int?,
     val sampleRateHz: Int?,
     val resolvedMimeType: MimeType
 )
+
+/**
+ * Represents the specific way to update a list of items in the detail lists.
+ * @author Alexander Capehart (OxygenCobalt)
+ */
+sealed class DetailListInstructions {
+    /** Do a plain asynchronous diff. */
+    object Diff : DetailListInstructions()
+
+    /**
+     * Replace all the items starting at the given index.
+     * @param at The index to start replacing at.
+     */
+    data class ReplaceRest(val at: Int) : DetailListInstructions()
+}

app/src/main/java/org/oxycblt/auxio/detail/DetailViewModel.kt

@@ -78,14 +78,18 @@ class DetailViewModel(application: Application) :
     /** The current list data derived from [currentAlbum]. */
     val albumList: StateFlow<List<Item>>
         get() = _albumList
+    /** Specifies how to update [albumList] when it changes. */
+    var albumListInstructions: DetailListInstructions? = null
+        private set
 
     /** The current [Sort] used for [Song]s in [albumList]. */
-    var albumSortSort: Sort
+    var albumSongSort: Sort
         get() = musicSettings.albumSongSort
         set(value) {
             musicSettings.albumSongSort = value
-            // Refresh the album list to reflect the new sort.
+            // Refresh the album list to reflect the new sort. Make sure we only visually replace
-            currentAlbum.value?.let(::refreshAlbumList)
+            // the song information, however.
+            currentAlbum.value?.let { refreshAlbumList(it, true) }
         }
 
     // --- ARTIST ---
@@ -98,14 +102,18 @@ class DetailViewModel(application: Application) :
     private val _artistList = MutableStateFlow(listOf<Item>())
     /** The current list derived from [currentArtist]. */
     val artistList: StateFlow<List<Item>> = _artistList
+    /** Specifies how to update [artistList] when it changes. */
+    var artistListInstructions: DetailListInstructions? = null
+        private set
 
     /** The current [Sort] used for [Song]s in [artistList]. */
     var artistSongSort: Sort
         get() = musicSettings.artistSongSort
         set(value) {
             musicSettings.artistSongSort = value
-            // Refresh the artist list to reflect the new sort.
+            // Refresh the artist list to reflect the new sort. Make sure we only visually replace
-            currentArtist.value?.let(::refreshArtistList)
+            // the song information, however.
+            currentArtist.value?.let { refreshArtistList(it, true) }
         }
 
     // --- GENRE ---
@@ -118,14 +126,18 @@ class DetailViewModel(application: Application) :
     private val _genreList = MutableStateFlow(listOf<Item>())
     /** The current list data derived from [currentGenre]. */
     val genreList: StateFlow<List<Item>> = _genreList
+    /** Specifies how to update [genreList] when it changes. */
+    var genreListInstructions: DetailListInstructions? = null
+        private set
 
     /** The current [Sort] used for [Song]s in [genreList]. */
     var genreSongSort: Sort
         get() = musicSettings.genreSongSort
         set(value) {
             musicSettings.genreSongSort = value
-            // Refresh the genre list to reflect the new sort.
+            // Refresh the genre list to reflect the new sort. Make sure we only visually replace
-            currentGenre.value?.let(::refreshGenreList)
+            // the song information, however.
+            currentGenre.value?.let { refreshGenreList(it, true) }
         }
 
     /**
@@ -161,19 +173,19 @@ class DetailViewModel(application: Application) :
 
         val album = currentAlbum.value
         if (album != null) {
-            _currentAlbum.value = library.sanitize(album)?.also(::refreshAlbumList)
+            _currentAlbum.value = library.sanitize(album)?.also { refreshAlbumList(it, false) }
             logD("Updated genre to ${currentAlbum.value}")
         }
 
         val artist = currentArtist.value
         if (artist != null) {
-            _currentArtist.value = library.sanitize(artist)?.also(::refreshArtistList)
+            _currentArtist.value = library.sanitize(artist)?.also { refreshArtistList(it, false) }
             logD("Updated genre to ${currentArtist.value}")
         }
 
         val genre = currentGenre.value
         if (genre != null) {
-            _currentGenre.value = library.sanitize(genre)?.also(::refreshGenreList)
+            _currentGenre.value = library.sanitize(genre)?.also { refreshGenreList(it, false) }
             logD("Updated genre to ${currentGenre.value}")
         }
     }
@@ -203,7 +215,7 @@ class DetailViewModel(application: Application) :
             return
         }
         logD("Opening Album [uid: $uid]")
-        _currentAlbum.value = requireMusic<Album>(uid)?.also(::refreshAlbumList)
+        _currentAlbum.value = requireMusic<Album>(uid)?.also { refreshAlbumList(it, false) }
     }
 
     /**
@@ -217,7 +229,7 @@ class DetailViewModel(application: Application) :
             return
         }
         logD("Opening Artist [uid: $uid]")
-        _currentArtist.value = requireMusic<Artist>(uid)?.also(::refreshArtistList)
+        _currentArtist.value = requireMusic<Artist>(uid)?.also { refreshArtistList(it, false) }
     }
 
     /**
@@ -231,7 +243,29 @@ class DetailViewModel(application: Application) :
             return
         }
         logD("Opening Genre [uid: $uid]")
-        _currentGenre.value = requireMusic<Genre>(uid)?.also(::refreshGenreList)
+        _currentGenre.value = requireMusic<Genre>(uid)?.also { refreshGenreList(it, false) }
+    }
+
+    /**
+     * Signal that the specified [DetailListInstructions] in [albumListInstructions] were performed.
+     */
+    fun finishAlbumListInstructions() {
+        albumListInstructions = null
+    }
+
+    /**
+     * Signal that the specified [DetailListInstructions] in [artistListInstructions] were
+     * performed.
+     */
+    fun finishArtistListInstructions() {
+        artistListInstructions = null
+    }
+
+    /**
+     * Signal that the specified [DetailListInstructions] in [genreListInstructions] were performed.
+     */
+    fun finishGenreListInstructions() {
+        genreListInstructions = null
     }
 
     private fun <T : Music> requireMusic(uid: Music.UID) = musicStore.library?.find<T>(uid)
@@ -314,14 +348,14 @@ class DetailViewModel(application: Application) :
         return SongProperties(bitrate, sampleRate, resolvedMimeType)
     }
 
-    private fun refreshAlbumList(album: Album) {
+    private fun refreshAlbumList(album: Album, replace: Boolean): Int {
         logD("Refreshing album data")
         val data = mutableListOf<Item>(album)
         data.add(SortHeader(R.string.lbl_songs))
-
+        val songsStartIndex = data.size
         // To create a good user experience regarding disc numbers, we group the album's
         // songs up by disc and then delimit the groups by a disc header.
-        val songs = albumSortSort.songs(album.songs)
+        val songs = albumSongSort.songs(album.songs)
         // Songs without disc tags become part of Disc 1.
         val byDisc = songs.groupBy { it.disc ?: 1 }
         if (byDisc.size > 1) {
@@ -334,11 +368,17 @@ class DetailViewModel(application: Application) :
             // Album only has one disc, don't add any redundant headers
             data.addAll(songs)
         }
-
+        albumListInstructions =
+            if (replace) {
+                DetailListInstructions.ReplaceRest(songsStartIndex)
+            } else {
+                DetailListInstructions.Diff
+            }
         _albumList.value = data
+        return songsStartIndex
     }
 
-    private fun refreshArtistList(artist: Artist) {
+    private fun refreshArtistList(artist: Artist, replace: Boolean) {
         logD("Refreshing artist data")
         val data = mutableListOf<Item>(artist)
         val albums = Sort(Sort.Mode.ByDate, false).albums(artist.albums)
@@ -371,24 +411,40 @@ class DetailViewModel(application: Application) :
             data.addAll(entry.value)
         }
 
+        var songsStartIndex: Int? = null
         // Artists may not be linked to any songs, only include a header entry if we have any.
         if (artist.songs.isNotEmpty()) {
             logD("Songs present in this artist, adding header")
             data.add(SortHeader(R.string.lbl_songs))
+            songsStartIndex = data.size
             data.addAll(artistSongSort.songs(artist.songs))
         }
 
+        artistListInstructions =
+            if (replace) {
+                DetailListInstructions.ReplaceRest(
+                    requireNotNull(songsStartIndex) { "Cannot replace empty artist song list" })
+            } else {
+                DetailListInstructions.Diff
+            }
         _artistList.value = data.toList()
     }
 
-    private fun refreshGenreList(genre: Genre) {
+    private fun refreshGenreList(genre: Genre, replace: Boolean) {
         logD("Refreshing genre data")
         val data = mutableListOf<Item>(genre)
         // Genre is guaranteed to always have artists and songs.
         data.add(Header(R.string.lbl_artists))
         data.addAll(genre.artists)
         data.add(SortHeader(R.string.lbl_songs))
+        val songsStartIndex = data.size
         data.addAll(genreSongSort.songs(genre.songs))
+        genreListInstructions =
+            if (replace) {
+                DetailListInstructions.ReplaceRest(songsStartIndex)
+            } else {
+                DetailListInstructions.Diff
+            }
         _genreList.value = data
     }
 

app/src/main/java/org/oxycblt/auxio/detail/GenreDetailFragment.kt

@@ -31,7 +31,6 @@ import org.oxycblt.auxio.detail.recycler.DetailAdapter
 import org.oxycblt.auxio.detail.recycler.GenreDetailAdapter
 import org.oxycblt.auxio.list.Item
 import org.oxycblt.auxio.list.ListFragment
-import org.oxycblt.auxio.list.recycler.BasicInstructions
 import org.oxycblt.auxio.music.Album
 import org.oxycblt.auxio.music.Artist
 import org.oxycblt.auxio.music.Genre
@@ -219,7 +218,9 @@ class GenreDetailFragment :
     }
 
     private fun updateList(items: List<Item>) {
-        detailAdapter.submitList(items, BasicInstructions.DIFF)
+        detailAdapter.submitList(
+            items, detailModel.genreListInstructions ?: DetailListInstructions.Diff)
+        detailModel.finishGenreListInstructions()
     }
 
     private fun updateSelection(selected: List<Music>) {

app/src/main/java/org/oxycblt/auxio/detail/recycler/AlbumDetailAdapter.kt

@@ -29,8 +29,8 @@ import org.oxycblt.auxio.databinding.ItemDiscHeaderBinding
 import org.oxycblt.auxio.detail.DiscHeader
 import org.oxycblt.auxio.list.Item
 import org.oxycblt.auxio.list.SelectableListListener
-import org.oxycblt.auxio.list.recycler.SelectionIndicatorAdapter
+import org.oxycblt.auxio.list.adapter.SelectionIndicatorAdapter
-import org.oxycblt.auxio.list.recycler.SimpleItemCallback
+import org.oxycblt.auxio.list.adapter.SimpleDiffCallback
 import org.oxycblt.auxio.music.Album
 import org.oxycblt.auxio.music.Song
 import org.oxycblt.auxio.playback.formatDurationMs
@@ -94,7 +94,7 @@ class AlbumDetailAdapter(private val listener: Listener) : DetailAdapter(listene
     private companion object {
         /** A comparator that can be used with DiffUtil. */
         val DIFF_CALLBACK =
-            object : SimpleItemCallback<Item>() {
+            object : SimpleDiffCallback<Item>() {
                 override fun areContentsTheSame(oldItem: Item, newItem: Item): Boolean {
                     return when {
                         oldItem is Album && newItem is Album ->
@@ -169,7 +169,7 @@ private class AlbumDetailViewHolder private constructor(private val binding: Ite
 
         /** A comparator that can be used with DiffUtil. */
         val DIFF_CALLBACK =
-            object : SimpleItemCallback<Album>() {
+            object : SimpleDiffCallback<Album>() {
                 override fun areContentsTheSame(oldItem: Album, newItem: Album) =
                     oldItem.rawName == newItem.rawName &&
                         oldItem.areArtistContentsTheSame(newItem) &&
@@ -210,7 +210,7 @@ private class DiscHeaderViewHolder(private val binding: ItemDiscHeaderBinding) :
 
         /** A comparator that can be used with DiffUtil. */
         val DIFF_CALLBACK =
-            object : SimpleItemCallback<DiscHeader>() {
+            object : SimpleDiffCallback<DiscHeader>() {
                 override fun areContentsTheSame(oldItem: DiscHeader, newItem: DiscHeader) =
                     oldItem.disc == newItem.disc
             }
@@ -277,7 +277,7 @@ private class AlbumSongViewHolder private constructor(private val binding: ItemA
 
         /** A comparator that can be used with DiffUtil. */
         val DIFF_CALLBACK =
-            object : SimpleItemCallback<Song>() {
+            object : SimpleDiffCallback<Song>() {
                 override fun areContentsTheSame(oldItem: Song, newItem: Song) =
                     oldItem.rawName == newItem.rawName && oldItem.durationMs == newItem.durationMs
             }

app/src/main/java/org/oxycblt/auxio/detail/recycler/ArtistDetailAdapter.kt

@@ -28,8 +28,8 @@ import org.oxycblt.auxio.databinding.ItemParentBinding
 import org.oxycblt.auxio.databinding.ItemSongBinding
 import org.oxycblt.auxio.list.Item
 import org.oxycblt.auxio.list.SelectableListListener
-import org.oxycblt.auxio.list.recycler.SelectionIndicatorAdapter
+import org.oxycblt.auxio.list.adapter.SelectionIndicatorAdapter
-import org.oxycblt.auxio.list.recycler.SimpleItemCallback
+import org.oxycblt.auxio.list.adapter.SimpleDiffCallback
 import org.oxycblt.auxio.music.Album
 import org.oxycblt.auxio.music.Artist
 import org.oxycblt.auxio.music.Music
@@ -83,7 +83,7 @@ class ArtistDetailAdapter(private val listener: Listener<Music>) :
     private companion object {
         /** A comparator that can be used with DiffUtil. */
         val DIFF_CALLBACK =
-            object : SimpleItemCallback<Item>() {
+            object : SimpleDiffCallback<Item>() {
                 override fun areContentsTheSame(oldItem: Item, newItem: Item): Boolean {
                     return when {
                         oldItem is Artist && newItem is Artist ->
@@ -165,7 +165,7 @@ private class ArtistDetailViewHolder private constructor(private val binding: It
 
         /** A comparator that can be used with DiffUtil. */
         val DIFF_CALLBACK =
-            object : SimpleItemCallback<Artist>() {
+            object : SimpleDiffCallback<Artist>() {
                 override fun areContentsTheSame(oldItem: Artist, newItem: Artist) =
                     oldItem.rawName == newItem.rawName &&
                         oldItem.areGenreContentsTheSame(newItem) &&
@@ -220,7 +220,7 @@ private class ArtistAlbumViewHolder private constructor(private val binding: Ite
 
         /** A comparator that can be used with DiffUtil. */
         val DIFF_CALLBACK =
-            object : SimpleItemCallback<Album>() {
+            object : SimpleDiffCallback<Album>() {
                 override fun areContentsTheSame(oldItem: Album, newItem: Album) =
                     oldItem.rawName == newItem.rawName && oldItem.dates == newItem.dates
             }
@@ -269,7 +269,7 @@ private class ArtistSongViewHolder private constructor(private val binding: Item
 
         /** A comparator that can be used with DiffUtil. */
         val DIFF_CALLBACK =
-            object : SimpleItemCallback<Song>() {
+            object : SimpleDiffCallback<Song>() {
                 override fun areContentsTheSame(oldItem: Song, newItem: Song) =
                     oldItem.rawName == newItem.rawName &&
                         oldItem.album.rawName == newItem.album.rawName

app/src/main/java/org/oxycblt/auxio/detail/recycler/DetailAdapter.kt

@@ -20,16 +20,24 @@ package org.oxycblt.auxio.detail.recycler
 import android.view.View
 import android.view.ViewGroup
 import androidx.appcompat.widget.TooltipCompat
+import androidx.recyclerview.widget.AdapterListUpdateCallback
+import androidx.recyclerview.widget.AsyncDifferConfig
+import androidx.recyclerview.widget.AsyncListDiffer
 import androidx.recyclerview.widget.DiffUtil
+import androidx.recyclerview.widget.ListUpdateCallback
 import androidx.recyclerview.widget.RecyclerView
 import org.oxycblt.auxio.IntegerTable
 import org.oxycblt.auxio.databinding.ItemSortHeaderBinding
+import org.oxycblt.auxio.detail.DetailListInstructions
 import org.oxycblt.auxio.detail.SortHeader
 import org.oxycblt.auxio.list.Header
 import org.oxycblt.auxio.list.Item
 import org.oxycblt.auxio.list.SelectableListListener
+import org.oxycblt.auxio.list.adapter.ListDiffer
+import org.oxycblt.auxio.list.adapter.SelectionIndicatorAdapter
+import org.oxycblt.auxio.list.adapter.SimpleDiffCallback
+import org.oxycblt.auxio.list.adapter.overwriteList
 import org.oxycblt.auxio.list.recycler.*
-import org.oxycblt.auxio.list.recycler.BasicInstructions
 import org.oxycblt.auxio.music.Music
 import org.oxycblt.auxio.util.context
 import org.oxycblt.auxio.util.inflater
@@ -45,8 +53,8 @@ abstract class DetailAdapter(
     private val listener: Listener<*>,
     diffCallback: DiffUtil.ItemCallback<Item>
 ) :
-    SelectionIndicatorAdapter<Item, BasicInstructions, RecyclerView.ViewHolder>(
+    SelectionIndicatorAdapter<Item, DetailListInstructions, RecyclerView.ViewHolder>(
-        ListDiffer.Async(diffCallback)),
+        DetailListDiffer.Factory(diffCallback)),
     AuxioRecyclerView.SpanSizeLookup {
 
     override fun getItemViewType(position: Int) =
@@ -102,7 +110,7 @@ abstract class DetailAdapter(
     protected companion object {
         /** A comparator that can be used with DiffUtil. */
         val DIFF_CALLBACK =
-            object : SimpleItemCallback<Item>() {
+            object : SimpleDiffCallback<Item>() {
                 override fun areContentsTheSame(oldItem: Item, newItem: Item): Boolean {
                     return when {
                         oldItem is Header && newItem is Header ->
@@ -116,6 +124,39 @@ abstract class DetailAdapter(
     }
 }
 
+private class DetailListDiffer<T>(
+    private val updateCallback: ListUpdateCallback,
+    diffCallback: DiffUtil.ItemCallback<T>
+) : ListDiffer<T, DetailListInstructions> {
+    private val inner =
+        AsyncListDiffer(updateCallback, AsyncDifferConfig.Builder(diffCallback).build())
+
+    override val currentList: List<T>
+        get() = inner.currentList
+
+    override fun submitList(
+        newList: List<T>,
+        instructions: DetailListInstructions,
+        onDone: () -> Unit
+    ) {
+        when (instructions) {
+            is DetailListInstructions.Diff -> inner.submitList(newList, onDone)
+            is DetailListInstructions.ReplaceRest -> {
+                val amount = newList.size - instructions.at
+                updateCallback.onRemoved(instructions.at, amount)
+                inner.overwriteList(newList)
+                updateCallback.onInserted(instructions.at, amount)
+            }
+        }
+    }
+
+    class Factory<T>(private val diffCallback: DiffUtil.ItemCallback<T>) :
+        ListDiffer.Factory<T, DetailListInstructions>() {
+        override fun new(adapter: RecyclerView.Adapter<*>) =
+            DetailListDiffer(AdapterListUpdateCallback(adapter), diffCallback)
+    }
+}
+
 /**
  * A [RecyclerView.ViewHolder] that displays a [SortHeader], a variation on [Header] that adds a
  * button opening a menu for sorting. Use [from] to create an instance.
@@ -152,7 +193,7 @@ private class SortHeaderViewHolder(private val binding: ItemSortHeaderBinding) :
 
         /** A comparator that can be used with DiffUtil. */
         val DIFF_CALLBACK =
-            object : SimpleItemCallback<SortHeader>() {
+            object : SimpleDiffCallback<SortHeader>() {
                 override fun areContentsTheSame(oldItem: SortHeader, newItem: SortHeader) =
                     oldItem.titleRes == newItem.titleRes
             }

app/src/main/java/org/oxycblt/auxio/detail/recycler/GenreDetailAdapter.kt

@@ -25,8 +25,8 @@ import org.oxycblt.auxio.IntegerTable
 import org.oxycblt.auxio.R
 import org.oxycblt.auxio.databinding.ItemDetailBinding
 import org.oxycblt.auxio.list.Item
+import org.oxycblt.auxio.list.adapter.SimpleDiffCallback
 import org.oxycblt.auxio.list.recycler.ArtistViewHolder
-import org.oxycblt.auxio.list.recycler.SimpleItemCallback
 import org.oxycblt.auxio.list.recycler.SongViewHolder
 import org.oxycblt.auxio.music.Artist
 import org.oxycblt.auxio.music.Genre
@@ -46,8 +46,8 @@ class GenreDetailAdapter(private val listener: Listener<Music>) :
     override fun getItemViewType(position: Int) =
         when (getItem(position)) {
             // Support the Genre header and generic Artist/Song items. There's nothing about
-            // a genre that will make the artists/songs homogeneous, so it doesn't matter what we
+            // a genre that will make the artists/songs specially formatted, so it doesn't matter
-            // use for their ViewHolders.
+            // what we use for their ViewHolders.
             is Genre -> GenreDetailViewHolder.VIEW_TYPE
             is Artist -> ArtistViewHolder.VIEW_TYPE
             is Song -> SongViewHolder.VIEW_TYPE
@@ -81,7 +81,7 @@ class GenreDetailAdapter(private val listener: Listener<Music>) :
 
     private companion object {
         val DIFF_CALLBACK =
-            object : SimpleItemCallback<Item>() {
+            object : SimpleDiffCallback<Item>() {
                 override fun areContentsTheSame(oldItem: Item, newItem: Item): Boolean {
                     return when {
                         oldItem is Genre && newItem is Genre ->
@@ -139,7 +139,7 @@ private class GenreDetailViewHolder private constructor(private val binding: Ite
 
         /** A comparator that can be used with DiffUtil. */
         val DIFF_CALLBACK =
-            object : SimpleItemCallback<Genre>() {
+            object : SimpleDiffCallback<Genre>() {
                 override fun areContentsTheSame(oldItem: Genre, newItem: Genre) =
                     oldItem.rawName == newItem.rawName &&
                         oldItem.songs.size == newItem.songs.size &&

app/src/main/java/org/oxycblt/auxio/home/HomeViewModel.kt

@@ -22,7 +22,7 @@ import androidx.lifecycle.AndroidViewModel
 import kotlinx.coroutines.flow.MutableStateFlow
 import kotlinx.coroutines.flow.StateFlow
 import org.oxycblt.auxio.home.tabs.Tab
-import org.oxycblt.auxio.list.recycler.BasicInstructions
+import org.oxycblt.auxio.list.adapter.BasicListInstructions
 import org.oxycblt.auxio.music.*
 import org.oxycblt.auxio.music.MusicStore
 import org.oxycblt.auxio.music.library.Library
@@ -46,7 +46,7 @@ class HomeViewModel(application: Application) :
     val songsList: StateFlow<List<Song>>
         get() = _songsList
     /** Specifies how to update [songsList] when it changes. */
-    var songsListInstructions: BasicInstructions? = null
+    var songsListInstructions: BasicListInstructions? = null
         private set
 
     private val _albumsLists = MutableStateFlow(listOf<Album>())
@@ -54,7 +54,7 @@ class HomeViewModel(application: Application) :
     val albumsList: StateFlow<List<Album>>
         get() = _albumsLists
     /** Specifies how to update [albumsList] when it changes. */
-    var albumsListInstructions: BasicInstructions? = null
+    var albumsListInstructions: BasicListInstructions? = null
         private set
 
     private val _artistsList = MutableStateFlow(listOf<Artist>())
@@ -66,7 +66,7 @@ class HomeViewModel(application: Application) :
     val artistsList: MutableStateFlow<List<Artist>>
         get() = _artistsList
     /** Specifies how to update [artistsList] when it changes. */
-    var artistsListInstructions: BasicInstructions? = null
+    var artistsListInstructions: BasicListInstructions? = null
         private set
 
     private val _genresList = MutableStateFlow(listOf<Genre>())
@@ -74,7 +74,7 @@ class HomeViewModel(application: Application) :
     val genresList: StateFlow<List<Genre>>
         get() = _genresList
     /** Specifies how to update [genresList] when it changes. */
-    var genresListInstructions: BasicInstructions? = null
+    var genresListInstructions: BasicListInstructions? = null
         private set
 
     /** The [MusicMode] to use when playing a [Song] from the UI. */
@@ -120,11 +120,11 @@ class HomeViewModel(application: Application) :
             logD("Library changed, refreshing library")
             // Get the each list of items in the library to use as our list data.
             // Applying the preferred sorting to them.
-            songsListInstructions = BasicInstructions.DIFF
+            songsListInstructions = BasicListInstructions.DIFF
             _songsList.value = musicSettings.songSort.songs(library.songs)
-            albumsListInstructions = BasicInstructions.DIFF
+            albumsListInstructions = BasicListInstructions.DIFF
             _albumsLists.value = musicSettings.albumSort.albums(library.albums)
-            artistsListInstructions = BasicInstructions.DIFF
+            artistsListInstructions = BasicListInstructions.DIFF
             _artistsList.value =
                 musicSettings.artistSort.artists(
                     if (homeSettings.shouldHideCollaborators) {
@@ -133,7 +133,7 @@ class HomeViewModel(application: Application) :
                     } else {
                         library.artists
                     })
-            genresListInstructions = BasicInstructions.DIFF
+            genresListInstructions = BasicListInstructions.DIFF
             _genresList.value = musicSettings.genreSort.genres(library.genres)
         }
     }
@@ -173,45 +173,52 @@ class HomeViewModel(application: Application) :
         when (_currentTabMode.value) {
             MusicMode.SONGS -> {
                 musicSettings.songSort = sort
-                songsListInstructions = BasicInstructions.REPLACE
+                songsListInstructions = BasicListInstructions.REPLACE
                 _songsList.value = sort.songs(_songsList.value)
             }
             MusicMode.ALBUMS -> {
                 musicSettings.albumSort = sort
-                albumsListInstructions = BasicInstructions.REPLACE
+                albumsListInstructions = BasicListInstructions.REPLACE
                 _albumsLists.value = sort.albums(_albumsLists.value)
             }
             MusicMode.ARTISTS -> {
                 musicSettings.artistSort = sort
-                artistsListInstructions = BasicInstructions.REPLACE
+                artistsListInstructions = BasicListInstructions.REPLACE
                 _artistsList.value = sort.artists(_artistsList.value)
             }
             MusicMode.GENRES -> {
                 musicSettings.genreSort = sort
-                genresListInstructions = BasicInstructions.REPLACE
+                genresListInstructions = BasicListInstructions.REPLACE
                 _genresList.value = sort.genres(_genresList.value)
             }
         }
     }
 
-    /** Signal that the specified [BasicInstructions] in [songsListInstructions] were performed. */
+    /**
+     * Signal that the specified [BasicListInstructions] in [songsListInstructions] were performed.
+     */
     fun finishSongsListInstructions() {
         songsListInstructions = null
     }
 
-    /** Signal that the specified [BasicInstructions] in [albumsListInstructions] were performed. */
+    /**
+     * Signal that the specified [BasicListInstructions] in [albumsListInstructions] were performed.
+     */
     fun finishAlbumsListInstructions() {
         albumsListInstructions = null
     }
 
     /**
-     * Signal that the specified [BasicInstructions] in [artistsListInstructions] were performed.
+     * Signal that the specified [BasicListInstructions] in [artistsListInstructions] were
+     * performed.
      */
     fun finishArtistsListInstructions() {
         artistsListInstructions = null
     }
 
-    /** Signal that the specified [BasicInstructions] in [genresListInstructions] were performed. */
+    /**
+     * Signal that the specified [BasicListInstructions] in [genresListInstructions] were performed.
+     */
     fun finishGenresListInstructions() {
         genresListInstructions = null
     }

app/src/main/java/org/oxycblt/auxio/home/list/AlbumListFragment.kt

@@ -30,10 +30,10 @@ import org.oxycblt.auxio.home.HomeViewModel
 import org.oxycblt.auxio.home.fastscroll.FastScrollRecyclerView
 import org.oxycblt.auxio.list.*
 import org.oxycblt.auxio.list.ListFragment
+import org.oxycblt.auxio.list.adapter.BasicListInstructions
+import org.oxycblt.auxio.list.adapter.ListDiffer
+import org.oxycblt.auxio.list.adapter.SelectionIndicatorAdapter
 import org.oxycblt.auxio.list.recycler.AlbumViewHolder
-import org.oxycblt.auxio.list.recycler.BasicInstructions
-import org.oxycblt.auxio.list.recycler.ListDiffer
-import org.oxycblt.auxio.list.recycler.SelectionIndicatorAdapter
 import org.oxycblt.auxio.music.*
 import org.oxycblt.auxio.music.library.Sort
 import org.oxycblt.auxio.playback.formatDurationMs
@@ -132,7 +132,8 @@ class AlbumListFragment :
     }
 
     private fun updateList(albums: List<Album>) {
-        albumAdapter.submitList(albums, homeModel.albumsListInstructions ?: BasicInstructions.DIFF)
+        albumAdapter.submitList(
+            albums, homeModel.albumsListInstructions ?: BasicListInstructions.DIFF)
         homeModel.finishAlbumsListInstructions()
     }
 
@@ -150,7 +151,7 @@ class AlbumListFragment :
      * @param listener An [SelectableListListener] to bind interactions to.
      */
     private class AlbumAdapter(private val listener: SelectableListListener<Album>) :
-        SelectionIndicatorAdapter<Album, BasicInstructions, AlbumViewHolder>(
+        SelectionIndicatorAdapter<Album, BasicListInstructions, AlbumViewHolder>(
             ListDiffer.Async(AlbumViewHolder.DIFF_CALLBACK)) {
 
         override fun onCreateViewHolder(parent: ViewGroup, viewType: Int) =

app/src/main/java/org/oxycblt/auxio/home/list/ArtistListFragment.kt

@@ -28,10 +28,10 @@ import org.oxycblt.auxio.home.HomeViewModel
 import org.oxycblt.auxio.home.fastscroll.FastScrollRecyclerView
 import org.oxycblt.auxio.list.*
 import org.oxycblt.auxio.list.ListFragment
+import org.oxycblt.auxio.list.adapter.BasicListInstructions
+import org.oxycblt.auxio.list.adapter.ListDiffer
+import org.oxycblt.auxio.list.adapter.SelectionIndicatorAdapter
 import org.oxycblt.auxio.list.recycler.ArtistViewHolder
-import org.oxycblt.auxio.list.recycler.BasicInstructions
-import org.oxycblt.auxio.list.recycler.ListDiffer
-import org.oxycblt.auxio.list.recycler.SelectionIndicatorAdapter
 import org.oxycblt.auxio.music.Artist
 import org.oxycblt.auxio.music.Music
 import org.oxycblt.auxio.music.MusicMode
@@ -111,7 +111,7 @@ class ArtistListFragment :
 
     private fun updateList(artists: List<Artist>) {
         artistAdapter.submitList(
-            artists, homeModel.artistsListInstructions ?: BasicInstructions.DIFF)
+            artists, homeModel.artistsListInstructions ?: BasicListInstructions.DIFF)
         homeModel.finishArtistsListInstructions()
     }
 
@@ -129,7 +129,7 @@ class ArtistListFragment :
      * @param listener An [SelectableListListener] to bind interactions to.
      */
     private class ArtistAdapter(private val listener: SelectableListListener<Artist>) :
-        SelectionIndicatorAdapter<Artist, BasicInstructions, ArtistViewHolder>(
+        SelectionIndicatorAdapter<Artist, BasicListInstructions, ArtistViewHolder>(
             ListDiffer.Async(ArtistViewHolder.DIFF_CALLBACK)) {
 
         override fun onCreateViewHolder(parent: ViewGroup, viewType: Int) =

app/src/main/java/org/oxycblt/auxio/home/list/GenreListFragment.kt

@@ -28,10 +28,10 @@ import org.oxycblt.auxio.home.HomeViewModel
 import org.oxycblt.auxio.home.fastscroll.FastScrollRecyclerView
 import org.oxycblt.auxio.list.*
 import org.oxycblt.auxio.list.ListFragment
-import org.oxycblt.auxio.list.recycler.BasicInstructions
+import org.oxycblt.auxio.list.adapter.BasicListInstructions
+import org.oxycblt.auxio.list.adapter.ListDiffer
+import org.oxycblt.auxio.list.adapter.SelectionIndicatorAdapter
 import org.oxycblt.auxio.list.recycler.GenreViewHolder
-import org.oxycblt.auxio.list.recycler.ListDiffer
-import org.oxycblt.auxio.list.recycler.SelectionIndicatorAdapter
 import org.oxycblt.auxio.music.Genre
 import org.oxycblt.auxio.music.Music
 import org.oxycblt.auxio.music.MusicMode
@@ -109,7 +109,8 @@ class GenreListFragment :
     }
 
     private fun updateList(artists: List<Genre>) {
-        genreAdapter.submitList(artists, homeModel.genresListInstructions ?: BasicInstructions.DIFF)
+        genreAdapter.submitList(
+            artists, homeModel.genresListInstructions ?: BasicListInstructions.DIFF)
         homeModel.finishGenresListInstructions()
     }
 
@@ -127,7 +128,7 @@ class GenreListFragment :
      * @param listener An [SelectableListListener] to bind interactions to.
      */
     private class GenreAdapter(private val listener: SelectableListListener<Genre>) :
-        SelectionIndicatorAdapter<Genre, BasicInstructions, GenreViewHolder>(
+        SelectionIndicatorAdapter<Genre, BasicListInstructions, GenreViewHolder>(
             ListDiffer.Async(GenreViewHolder.DIFF_CALLBACK)) {
         override fun onCreateViewHolder(parent: ViewGroup, viewType: Int) =
             GenreViewHolder.from(parent)

app/src/main/java/org/oxycblt/auxio/home/list/SongListFragment.kt

@@ -30,9 +30,9 @@ import org.oxycblt.auxio.home.HomeViewModel
 import org.oxycblt.auxio.home.fastscroll.FastScrollRecyclerView
 import org.oxycblt.auxio.list.*
 import org.oxycblt.auxio.list.ListFragment
-import org.oxycblt.auxio.list.recycler.BasicInstructions
+import org.oxycblt.auxio.list.adapter.BasicListInstructions
-import org.oxycblt.auxio.list.recycler.ListDiffer
+import org.oxycblt.auxio.list.adapter.ListDiffer
-import org.oxycblt.auxio.list.recycler.SelectionIndicatorAdapter
+import org.oxycblt.auxio.list.adapter.SelectionIndicatorAdapter
 import org.oxycblt.auxio.list.recycler.SongViewHolder
 import org.oxycblt.auxio.music.Music
 import org.oxycblt.auxio.music.MusicMode
@@ -139,7 +139,7 @@ class SongListFragment :
     }
 
     private fun updateList(songs: List<Song>) {
-        songAdapter.submitList(songs, homeModel.songsListInstructions ?: BasicInstructions.DIFF)
+        songAdapter.submitList(songs, homeModel.songsListInstructions ?: BasicListInstructions.DIFF)
         homeModel.finishSongsListInstructions()
     }
 
@@ -161,7 +161,7 @@ class SongListFragment :
      * @param listener An [SelectableListListener] to bind interactions to.
      */
     private class SongAdapter(private val listener: SelectableListListener<Song>) :
-        SelectionIndicatorAdapter<Song, BasicInstructions, SongViewHolder>(
+        SelectionIndicatorAdapter<Song, BasicListInstructions, SongViewHolder>(
             ListDiffer.Async(SongViewHolder.DIFF_CALLBACK)) {
 
         override fun onCreateViewHolder(parent: ViewGroup, viewType: Int) =

app/src/main/java/org/oxycblt/auxio/list/Data.kt

@@ -25,6 +25,5 @@ interface Item
 /**
  * A "header" used for delimiting groups of data.
  * @param titleRes The string resource used for the header's title.
- * @param withDivider Whether to show a divider on the item.
  */
 data class Header(@StringRes val titleRes: Int) : Item

app/src/main/java/org/oxycblt/auxio/list/adapter/AdapterUtil.kt

@@ -0,0 +1,42 @@
+/*
+ * Copyright (c) 2023 Auxio Project
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+ 
+package org.oxycblt.auxio.list.adapter
+
+import androidx.recyclerview.widget.AsyncListDiffer
+import java.lang.reflect.Field
+import org.oxycblt.auxio.util.lazyReflectedField
+import org.oxycblt.auxio.util.requireIs
+
+val ASD_MAX_GENERATION_FIELD: Field by
+    lazyReflectedField(AsyncListDiffer::class, "mMaxScheduledGeneration")
+val ASD_MUTABLE_LIST_FIELD: Field by lazyReflectedField(AsyncListDiffer::class, "mList")
+val ASD_READ_ONLY_LIST_FIELD: Field by lazyReflectedField(AsyncListDiffer::class, "mReadOnlyList")
+
+/**
+ * Force-update an [AsyncListDiffer] with new data. It's hard to state how incredibly dangerous this
+ * is, so only use it when absolutely necessary.
+ * @param newList The new list to write to the [AsyncListDiffer].
+ */
+fun <T> AsyncListDiffer<T>.overwriteList(newList: List<T>) {
+    // Should update the generation field to prevent any previous jobs from conflicting, then
+    // updates the mutable list to it's nullable value, and then updates the read-only list to
+    // it's non-nullable value.
+    ASD_MAX_GENERATION_FIELD.set(this, requireIs<Int>(ASD_MAX_GENERATION_FIELD.get(this)) + 1)
+    ASD_MUTABLE_LIST_FIELD.set(this, newList.ifEmpty { null })
+    ASD_READ_ONLY_LIST_FIELD.set(this, newList)
+}

app/src/main/java/org/oxycblt/auxio/list/adapter/DiffAdapter.kt

@@ -15,7 +15,7 @@
  * along with this program.  If not, see <https://www.gnu.org/licenses/>.
  */
  
-package org.oxycblt.auxio.list.recycler
+package org.oxycblt.auxio.list.adapter
 
 import androidx.recyclerview.widget.RecyclerView
 

app/src/main/java/org/oxycblt/auxio/list/adapter/ListDiffer.kt

@@ -15,7 +15,7 @@
  * along with this program.  If not, see <https://www.gnu.org/licenses/>.
  */
  
-package org.oxycblt.auxio.list.recycler
+package org.oxycblt.auxio.list.adapter
 
 import androidx.recyclerview.widget.AdapterListUpdateCallback
 import androidx.recyclerview.widget.AsyncDifferConfig
@@ -23,9 +23,6 @@ import androidx.recyclerview.widget.AsyncListDiffer
 import androidx.recyclerview.widget.DiffUtil
 import androidx.recyclerview.widget.ListUpdateCallback
 import androidx.recyclerview.widget.RecyclerView
-import java.lang.reflect.Field
-import org.oxycblt.auxio.util.lazyReflectedField
-import org.oxycblt.auxio.util.requireIs
 
 /**
  * List differ wrapper that provides more flexibility regarding the way lists are updated.
@@ -38,7 +35,7 @@ interface ListDiffer<T, I> {
     /**
      * Dynamically determine how to update the list based on the given instructions.
      * @param newList The new list of [T] items to show.
-     * @param instructions The [BasicInstructions] specifying how to update the list.
+     * @param instructions The [BasicListInstructions] specifying how to update the list.
      * @param onDone Called when the update process is completed.
      */
     fun submitList(newList: List<T>, instructions: I, onDone: () -> Unit)
@@ -62,20 +59,20 @@ interface ListDiffer<T, I> {
      * internal list.
      */
     class Async<T>(private val diffCallback: DiffUtil.ItemCallback<T>) :
-        Factory<T, BasicInstructions>() {
+        Factory<T, BasicListInstructions>() {
-        override fun new(adapter: RecyclerView.Adapter<*>): ListDiffer<T, BasicInstructions> =
+        override fun new(adapter: RecyclerView.Adapter<*>): ListDiffer<T, BasicListInstructions> =
             RealAsyncListDiffer(AdapterListUpdateCallback(adapter), diffCallback)
     }
 
     /**
      * Update lists on the main thread. This is useful when many small, discrete list diffs are
-     * likely to occur that would cause [Async] to get race conditions.
+     * likely to occur that would cause [Async] to suffer from race conditions.
      * @param diffCallback A [DiffUtil.ItemCallback] to use for item comparison when diffing the
      * internal list.
      */
     class Blocking<T>(private val diffCallback: DiffUtil.ItemCallback<T>) :
-        Factory<T, BasicInstructions>() {
+        Factory<T, BasicListInstructions>() {
-        override fun new(adapter: RecyclerView.Adapter<*>): ListDiffer<T, BasicInstructions> =
+        override fun new(adapter: RecyclerView.Adapter<*>): ListDiffer<T, BasicListInstructions> =
             RealBlockingListDiffer(AdapterListUpdateCallback(adapter), diffCallback)
     }
 }
@@ -84,7 +81,7 @@ interface ListDiffer<T, I> {
  * Represents the specific way to update a list of items.
  * @author Alexander Capehart (OxygenCobalt)
  */
-enum class BasicInstructions {
+enum class BasicListInstructions {
     /**
      * (A)synchronously diff the list. This should be used for small diffs with little item
      * movement.
@@ -98,11 +95,15 @@ enum class BasicInstructions {
     REPLACE
 }
 
-private abstract class RealListDiffer<T>() : ListDiffer<T, BasicInstructions> {
+private abstract class BasicListDiffer<T>() : ListDiffer<T, BasicListInstructions> {
-    override fun submitList(newList: List<T>, instructions: BasicInstructions, onDone: () -> Unit) {
+    override fun submitList(
+        newList: List<T>,
+        instructions: BasicListInstructions,
+        onDone: () -> Unit
+    ) {
         when (instructions) {
-            BasicInstructions.DIFF -> diffList(newList, onDone)
+            BasicListInstructions.DIFF -> diffList(newList, onDone)
-            BasicInstructions.REPLACE -> replaceList(newList, onDone)
+            BasicListInstructions.REPLACE -> replaceList(newList, onDone)
         }
     }
 
@@ -113,7 +114,7 @@ private abstract class RealListDiffer<T>() : ListDiffer<T, BasicInstructions> {
 private class RealAsyncListDiffer<T>(
     private val updateCallback: ListUpdateCallback,
     diffCallback: DiffUtil.ItemCallback<T>
-) : RealListDiffer<T>() {
+) : BasicListDiffer<T>() {
     private val inner =
         AsyncListDiffer(updateCallback, AsyncDifferConfig.Builder(diffCallback).build())
 
@@ -126,34 +127,19 @@ private class RealAsyncListDiffer<T>(
 
     override fun replaceList(newList: List<T>, onDone: () -> Unit) {
         if (inner.currentList != newList) {
-            // Do possibly the most idiotic thing possible and mutate the internal differ state
-            // so we don't have to deal with any disjoint list garbage. This should cancel any prior
-            // updates and correctly set up the list values while still allowing for the same
-            // visual animation as the blocking replaceList.
             val oldListSize = inner.currentList.size
-            ASD_MAX_GENERATION_FIELD.set(
-                inner, requireIs<Int>(ASD_MAX_GENERATION_FIELD.get(inner)) + 1)
-            ASD_MUTABLE_LIST_FIELD.set(inner, newList.ifEmpty { null })
-            ASD_READ_ONLY_LIST_FIELD.set(inner, newList)
             updateCallback.onRemoved(0, oldListSize)
+            inner.overwriteList(newList)
             updateCallback.onInserted(0, newList.size)
         }
         onDone()
     }
-
-    private companion object {
-        val ASD_MAX_GENERATION_FIELD: Field by
-            lazyReflectedField(AsyncListDiffer::class, "mMaxScheduledGeneration")
-        val ASD_MUTABLE_LIST_FIELD: Field by lazyReflectedField(AsyncListDiffer::class, "mList")
-        val ASD_READ_ONLY_LIST_FIELD: Field by
-            lazyReflectedField(AsyncListDiffer::class, "mReadOnlyList")
-    }
 }
 
 private class RealBlockingListDiffer<T>(
     private val updateCallback: ListUpdateCallback,
     private val diffCallback: DiffUtil.ItemCallback<T>
-) : RealListDiffer<T>() {
+) : BasicListDiffer<T>() {
     override var currentList = listOf<T>()
 
     override fun diffList(newList: List<T>, onDone: () -> Unit) {

app/src/main/java/org/oxycblt/auxio/list/adapter/PlayingIndicatorAdapter.kt

@@ -15,7 +15,7 @@
  * along with this program.  If not, see <https://www.gnu.org/licenses/>.
  */
  
-package org.oxycblt.auxio.list.recycler
+package org.oxycblt.auxio.list.adapter
 
 import android.view.View
 import androidx.recyclerview.widget.RecyclerView

app/src/main/java/org/oxycblt/auxio/list/adapter/SelectionIndicatorAdapter.kt

@@ -15,7 +15,7 @@
  * along with this program.  If not, see <https://www.gnu.org/licenses/>.
  */
  
-package org.oxycblt.auxio.list.recycler
+package org.oxycblt.auxio.list.adapter
 
 import android.view.View
 import androidx.recyclerview.widget.RecyclerView

app/src/main/java/org/oxycblt/auxio/list/adapter/SimpleDiffCallback.kt

@@ -15,7 +15,7 @@
  * along with this program.  If not, see <https://www.gnu.org/licenses/>.
  */
  
-package org.oxycblt.auxio.list.recycler
+package org.oxycblt.auxio.list.adapter
 
 import androidx.recyclerview.widget.DiffUtil
 import org.oxycblt.auxio.list.Item
@@ -25,6 +25,6 @@ import org.oxycblt.auxio.list.Item
  * whenever creating [DiffUtil.ItemCallback] implementations with an [Item] subclass.
  * @author Alexander Capehart (OxygenCobalt)
  */
-abstract class SimpleItemCallback<T : Item> : DiffUtil.ItemCallback<T>() {
+abstract class SimpleDiffCallback<T : Item> : DiffUtil.ItemCallback<T>() {
     final override fun areItemsTheSame(oldItem: T, newItem: T) = oldItem == newItem
 }

app/src/main/java/org/oxycblt/auxio/list/recycler/HeaderItemDecoration.kt

@@ -24,6 +24,7 @@ import androidx.recyclerview.widget.RecyclerView
 import com.google.android.material.divider.BackportMaterialDividerItemDecoration
 import org.oxycblt.auxio.R
 import org.oxycblt.auxio.list.Header
+import org.oxycblt.auxio.list.adapter.DiffAdapter
 
 /**
  * A [BackportMaterialDividerItemDecoration] that sets up the divider configuration to correctly

app/src/main/java/org/oxycblt/auxio/list/recycler/ViewHolders.kt

@@ -26,6 +26,8 @@ import org.oxycblt.auxio.databinding.ItemParentBinding
 import org.oxycblt.auxio.databinding.ItemSongBinding
 import org.oxycblt.auxio.list.Header
 import org.oxycblt.auxio.list.SelectableListListener
+import org.oxycblt.auxio.list.adapter.SelectionIndicatorAdapter
+import org.oxycblt.auxio.list.adapter.SimpleDiffCallback
 import org.oxycblt.auxio.music.*
 import org.oxycblt.auxio.util.context
 import org.oxycblt.auxio.util.getPlural
@@ -72,7 +74,7 @@ class SongViewHolder private constructor(private val binding: ItemSongBinding) :
 
         /** A comparator that can be used with DiffUtil. */
         val DIFF_CALLBACK =
-            object : SimpleItemCallback<Song>() {
+            object : SimpleDiffCallback<Song>() {
                 override fun areContentsTheSame(oldItem: Song, newItem: Song) =
                     oldItem.rawName == newItem.rawName && oldItem.areArtistContentsTheSame(newItem)
             }
@@ -119,7 +121,7 @@ class AlbumViewHolder private constructor(private val binding: ItemParentBinding
 
         /** A comparator that can be used with DiffUtil. */
         val DIFF_CALLBACK =
-            object : SimpleItemCallback<Album>() {
+            object : SimpleDiffCallback<Album>() {
                 override fun areContentsTheSame(oldItem: Album, newItem: Album) =
                     oldItem.rawName == newItem.rawName &&
                         oldItem.areArtistContentsTheSame(newItem) &&
@@ -178,7 +180,7 @@ class ArtistViewHolder private constructor(private val binding: ItemParentBindin
 
         /** A comparator that can be used with DiffUtil. */
         val DIFF_CALLBACK =
-            object : SimpleItemCallback<Artist>() {
+            object : SimpleDiffCallback<Artist>() {
                 override fun areContentsTheSame(oldItem: Artist, newItem: Artist) =
                     oldItem.rawName == newItem.rawName &&
                         oldItem.albums.size == newItem.albums.size &&
@@ -231,7 +233,7 @@ class GenreViewHolder private constructor(private val binding: ItemParentBinding
 
         /** A comparator that can be used with DiffUtil. */
         val DIFF_CALLBACK =
-            object : SimpleItemCallback<Genre>() {
+            object : SimpleDiffCallback<Genre>() {
                 override fun areContentsTheSame(oldItem: Genre, newItem: Genre): Boolean =
                     oldItem.rawName == newItem.rawName && oldItem.songs.size == newItem.songs.size
             }
@@ -267,7 +269,7 @@ class HeaderViewHolder private constructor(private val binding: ItemHeaderBindin
 
         /** A comparator that can be used with DiffUtil. */
         val DIFF_CALLBACK =
-            object : SimpleItemCallback<Header>() {
+            object : SimpleDiffCallback<Header>() {
                 override fun areContentsTheSame(oldItem: Header, newItem: Header): Boolean =
                     oldItem.titleRes == newItem.titleRes
             }

app/src/main/java/org/oxycblt/auxio/playback/queue/QueueAdapter.kt

@@ -27,10 +27,10 @@ import com.google.android.material.shape.MaterialShapeDrawable
 import org.oxycblt.auxio.R
 import org.oxycblt.auxio.databinding.ItemQueueSongBinding
 import org.oxycblt.auxio.list.EditableListListener
-import org.oxycblt.auxio.list.recycler.BasicInstructions
+import org.oxycblt.auxio.list.adapter.BasicListInstructions
-import org.oxycblt.auxio.list.recycler.DiffAdapter
+import org.oxycblt.auxio.list.adapter.DiffAdapter
-import org.oxycblt.auxio.list.recycler.ListDiffer
+import org.oxycblt.auxio.list.adapter.ListDiffer
-import org.oxycblt.auxio.list.recycler.PlayingIndicatorAdapter
+import org.oxycblt.auxio.list.adapter.PlayingIndicatorAdapter
 import org.oxycblt.auxio.list.recycler.SongViewHolder
 import org.oxycblt.auxio.music.Song
 import org.oxycblt.auxio.util.*
@@ -41,7 +41,7 @@ import org.oxycblt.auxio.util.*
  * @author Alexander Capehart (OxygenCobalt)
  */
 class QueueAdapter(private val listener: EditableListListener<Song>) :
-    DiffAdapter<Song, BasicInstructions, QueueSongViewHolder>(
+    DiffAdapter<Song, BasicListInstructions, QueueSongViewHolder>(
         ListDiffer.Blocking(QueueSongViewHolder.DIFF_CALLBACK)) {
     // Since PlayingIndicator adapter relies on an item value, we cannot use it for this
     // adapter, as one item can appear at several points in the UI. Use a similar implementation

app/src/main/java/org/oxycblt/auxio/playback/queue/QueueFragment.kt

@@ -27,7 +27,7 @@ import androidx.recyclerview.widget.RecyclerView
 import kotlin.math.min
 import org.oxycblt.auxio.databinding.FragmentQueueBinding
 import org.oxycblt.auxio.list.EditableListListener
-import org.oxycblt.auxio.list.recycler.BasicInstructions
+import org.oxycblt.auxio.list.adapter.BasicListInstructions
 import org.oxycblt.auxio.music.Song
 import org.oxycblt.auxio.playback.PlaybackViewModel
 import org.oxycblt.auxio.ui.ViewBindingFragment
@@ -101,7 +101,7 @@ class QueueFragment : ViewBindingFragment<FragmentQueueBinding>(), EditableListL
 
         // Replace or diff the queue depending on the type of change it is.
         val instructions = queueModel.instructions
-        queueAdapter.submitList(queue, instructions?.update ?: BasicInstructions.DIFF)
+        queueAdapter.submitList(queue, instructions?.update ?: BasicListInstructions.DIFF)
         // Update position in list (and thus past/future items)
         queueAdapter.setPosition(index, isPlaying)
 

app/src/main/java/org/oxycblt/auxio/playback/queue/QueueViewModel.kt

@@ -20,7 +20,7 @@ package org.oxycblt.auxio.playback.queue
 import androidx.lifecycle.ViewModel
 import kotlinx.coroutines.flow.MutableStateFlow
 import kotlinx.coroutines.flow.StateFlow
-import org.oxycblt.auxio.list.recycler.BasicInstructions
+import org.oxycblt.auxio.list.adapter.BasicListInstructions
 import org.oxycblt.auxio.music.MusicParent
 import org.oxycblt.auxio.music.Song
 import org.oxycblt.auxio.playback.state.PlaybackStateManager
@@ -57,7 +57,7 @@ class QueueViewModel : ViewModel(), PlaybackStateManager.Listener {
 
     override fun onQueueChanged(queue: Queue, change: Queue.ChangeResult) {
         // Queue changed trivially due to item mo -> Diff queue, stay at current index.
-        instructions = Instructions(BasicInstructions.DIFF, null)
+        instructions = Instructions(BasicListInstructions.DIFF, null)
         _queue.value = queue.resolve()
         if (change != Queue.ChangeResult.MAPPING) {
             // Index changed, make sure it remains updated without actually scrolling to it.
@@ -67,14 +67,14 @@ class QueueViewModel : ViewModel(), PlaybackStateManager.Listener {
 
     override fun onQueueReordered(queue: Queue) {
         // Queue changed completely -> Replace queue, update index
-        instructions = Instructions(BasicInstructions.REPLACE, queue.index)
+        instructions = Instructions(BasicListInstructions.REPLACE, queue.index)
         _queue.value = queue.resolve()
         _index.value = queue.index
     }
 
     override fun onNewPlayback(queue: Queue, parent: MusicParent?) {
         // Entirely new queue -> Replace queue, update index
-        instructions = Instructions(BasicInstructions.REPLACE, queue.index)
+        instructions = Instructions(BasicListInstructions.REPLACE, queue.index)
         _queue.value = queue.resolve()
         _index.value = queue.index
     }
@@ -124,5 +124,5 @@ class QueueViewModel : ViewModel(), PlaybackStateManager.Listener {
         instructions = null
     }
 
-    class Instructions(val update: BasicInstructions?, val scrollTo: Int?)
+    class Instructions(val update: BasicListInstructions?, val scrollTo: Int?)
 }

app/src/main/java/org/oxycblt/auxio/search/SearchAdapter.kt

@@ -20,6 +20,10 @@ package org.oxycblt.auxio.search
 import android.view.ViewGroup
 import androidx.recyclerview.widget.RecyclerView
 import org.oxycblt.auxio.list.*
+import org.oxycblt.auxio.list.adapter.BasicListInstructions
+import org.oxycblt.auxio.list.adapter.ListDiffer
+import org.oxycblt.auxio.list.adapter.SelectionIndicatorAdapter
+import org.oxycblt.auxio.list.adapter.SimpleDiffCallback
 import org.oxycblt.auxio.list.recycler.*
 import org.oxycblt.auxio.music.*
 import org.oxycblt.auxio.util.logD
@@ -30,7 +34,7 @@ import org.oxycblt.auxio.util.logD
  * @author Alexander Capehart (OxygenCobalt)
  */
 class SearchAdapter(private val listener: SelectableListListener<Music>) :
-    SelectionIndicatorAdapter<Item, BasicInstructions, RecyclerView.ViewHolder>(
+    SelectionIndicatorAdapter<Item, BasicListInstructions, RecyclerView.ViewHolder>(
         ListDiffer.Async(DIFF_CALLBACK)),
     AuxioRecyclerView.SpanSizeLookup {
 
@@ -79,7 +83,7 @@ class SearchAdapter(private val listener: SelectableListListener<Music>) :
         val PAYLOAD_UPDATE_DIVIDER = 102249124
         /** A comparator that can be used with DiffUtil. */
         val DIFF_CALLBACK =
-            object : SimpleItemCallback<Item>() {
+            object : SimpleDiffCallback<Item>() {
                 override fun areContentsTheSame(oldItem: Item, newItem: Item) =
                     when {
                         oldItem is Song && newItem is Song ->

app/src/main/java/org/oxycblt/auxio/search/SearchFragment.kt

@@ -31,7 +31,7 @@ import org.oxycblt.auxio.R
 import org.oxycblt.auxio.databinding.FragmentSearchBinding
 import org.oxycblt.auxio.list.Item
 import org.oxycblt.auxio.list.ListFragment
-import org.oxycblt.auxio.list.recycler.BasicInstructions
+import org.oxycblt.auxio.list.adapter.BasicListInstructions
 import org.oxycblt.auxio.music.Album
 import org.oxycblt.auxio.music.Artist
 import org.oxycblt.auxio.music.Genre
@@ -154,7 +154,7 @@ class SearchFragment : ListFragment<Music, FragmentSearchBinding>() {
         // Don't show the RecyclerView (and it's stray overscroll effects) when there
         // are no results.
         binding.searchRecycler.isInvisible = results.isEmpty()
-        searchAdapter.submitList(results.toMutableList(), BasicInstructions.DIFF) {
+        searchAdapter.submitList(results.toMutableList(), BasicListInstructions.DIFF) {
             // I would make it so that the position is only scrolled back to the top when
             // the query actually changes instead of once every re-creation event, but sadly
             // that doesn't seem possible.