picker: refactor into module-specific impls

Refactor the weird picker god module into specific sub-impls in
playback and a new navigation package.

I cannot keep this unified. The needs are too different among each
picker. Better to keep it separate, especially in preparation for
the playlist dialogs.

CHANGELOG.md

@@ -2,6 +2,9 @@
 
 ## dev
 
+## What's Fixed
+- Fixed inconsistent corner radius on widget cover art
+
 ## What's Improved
 - Added ability to click on the playback bar to exit the queue view
 

app/src/main/java/org/oxycblt/auxio/MainActivity.kt

@@ -48,6 +48,9 @@ import org.oxycblt.auxio.util.systemBarInsetsCompat
  * TODO: Use proper material attributes (Not the weird dimen attributes I currently have)
  * TODO: Migrate to material animation system
  * TODO: Unit testing
+ * TODO: Use sealed interface where applicable
+ * TODO: Fix UID naming
+ * TODO: Leverage FlexibleListAdapter more in dialogs (Disable item anims)
  */
 @AndroidEntryPoint
 class MainActivity : AppCompatActivity() {

app/src/main/java/org/oxycblt/auxio/MainFragment.kt

@@ -41,11 +41,11 @@ import org.oxycblt.auxio.databinding.FragmentMainBinding
 import org.oxycblt.auxio.list.selection.SelectionViewModel
 import org.oxycblt.auxio.music.Music
 import org.oxycblt.auxio.music.Song
+import org.oxycblt.auxio.navigation.MainNavigationAction
+import org.oxycblt.auxio.navigation.NavigationViewModel
 import org.oxycblt.auxio.playback.PlaybackBottomSheetBehavior
 import org.oxycblt.auxio.playback.PlaybackViewModel
 import org.oxycblt.auxio.playback.queue.QueueBottomSheetBehavior
-import org.oxycblt.auxio.ui.MainNavigationAction
-import org.oxycblt.auxio.ui.NavigationViewModel
 import org.oxycblt.auxio.ui.ViewBindingFragment
 import org.oxycblt.auxio.util.*
 

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

@@ -44,8 +44,8 @@ import org.oxycblt.auxio.music.Music
 import org.oxycblt.auxio.music.MusicMode
 import org.oxycblt.auxio.music.MusicParent
 import org.oxycblt.auxio.music.Song
+import org.oxycblt.auxio.navigation.NavigationViewModel
 import org.oxycblt.auxio.playback.PlaybackViewModel
-import org.oxycblt.auxio.ui.NavigationViewModel
 import org.oxycblt.auxio.util.*
 
 /**

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

@@ -43,8 +43,8 @@ import org.oxycblt.auxio.music.Artist
 import org.oxycblt.auxio.music.Music
 import org.oxycblt.auxio.music.MusicParent
 import org.oxycblt.auxio.music.Song
+import org.oxycblt.auxio.navigation.NavigationViewModel
 import org.oxycblt.auxio.playback.PlaybackViewModel
-import org.oxycblt.auxio.ui.NavigationViewModel
 import org.oxycblt.auxio.util.*
 
 /**

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

@@ -39,8 +39,8 @@ import org.oxycblt.auxio.list.ListFragment
 import org.oxycblt.auxio.list.Sort
 import org.oxycblt.auxio.list.selection.SelectionViewModel
 import org.oxycblt.auxio.music.*
+import org.oxycblt.auxio.navigation.NavigationViewModel
 import org.oxycblt.auxio.playback.PlaybackViewModel
-import org.oxycblt.auxio.ui.NavigationViewModel
 import org.oxycblt.auxio.util.*
 
 /**

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

@@ -39,8 +39,8 @@ import org.oxycblt.auxio.list.ListFragment
 import org.oxycblt.auxio.list.Sort
 import org.oxycblt.auxio.list.selection.SelectionViewModel
 import org.oxycblt.auxio.music.*
+import org.oxycblt.auxio.navigation.NavigationViewModel
 import org.oxycblt.auxio.playback.PlaybackViewModel
-import org.oxycblt.auxio.ui.NavigationViewModel
 import org.oxycblt.auxio.util.*
 
 /**

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

@@ -66,7 +66,7 @@ class SongDetailDialog : ViewBindingDialogFragment<DialogSongDetailBinding>() {
         super.onBindingCreated(binding, savedInstanceState)
         binding.detailProperties.adapter = detailAdapter
         // DetailViewModel handles most initialization from the navigation argument.
-        detailModel.setSongUid(args.itemUid)
+        detailModel.setSongUid(args.songUid)
         collectImmediately(detailModel.currentSong, detailModel.songAudioInfo, ::updateSong)
     }
 

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

@@ -52,9 +52,9 @@ import org.oxycblt.auxio.list.Sort
 import org.oxycblt.auxio.list.selection.SelectionFragment
 import org.oxycblt.auxio.list.selection.SelectionViewModel
 import org.oxycblt.auxio.music.*
+import org.oxycblt.auxio.navigation.MainNavigationAction
+import org.oxycblt.auxio.navigation.NavigationViewModel
 import org.oxycblt.auxio.playback.PlaybackViewModel
-import org.oxycblt.auxio.ui.MainNavigationAction
-import org.oxycblt.auxio.ui.NavigationViewModel
 import org.oxycblt.auxio.util.*
 
 /**

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

@@ -37,10 +37,10 @@ import org.oxycblt.auxio.list.adapter.SelectionIndicatorAdapter
 import org.oxycblt.auxio.list.recycler.AlbumViewHolder
 import org.oxycblt.auxio.list.selection.SelectionViewModel
 import org.oxycblt.auxio.music.*
+import org.oxycblt.auxio.navigation.NavigationViewModel
 import org.oxycblt.auxio.playback.PlaybackViewModel
 import org.oxycblt.auxio.playback.formatDurationMs
 import org.oxycblt.auxio.playback.secsToMs
-import org.oxycblt.auxio.ui.NavigationViewModel
 import org.oxycblt.auxio.util.collectImmediately
 
 /**

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

@@ -38,9 +38,9 @@ import org.oxycblt.auxio.music.Artist
 import org.oxycblt.auxio.music.Music
 import org.oxycblt.auxio.music.MusicMode
 import org.oxycblt.auxio.music.MusicParent
+import org.oxycblt.auxio.navigation.NavigationViewModel
 import org.oxycblt.auxio.playback.PlaybackViewModel
 import org.oxycblt.auxio.playback.formatDurationMs
-import org.oxycblt.auxio.ui.NavigationViewModel
 import org.oxycblt.auxio.util.collectImmediately
 import org.oxycblt.auxio.util.logD
 import org.oxycblt.auxio.util.nonZeroOrNull

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

@@ -38,9 +38,9 @@ import org.oxycblt.auxio.music.Genre
 import org.oxycblt.auxio.music.Music
 import org.oxycblt.auxio.music.MusicMode
 import org.oxycblt.auxio.music.MusicParent
+import org.oxycblt.auxio.navigation.NavigationViewModel
 import org.oxycblt.auxio.playback.PlaybackViewModel
 import org.oxycblt.auxio.playback.formatDurationMs
-import org.oxycblt.auxio.ui.NavigationViewModel
 import org.oxycblt.auxio.util.collectImmediately
 import org.oxycblt.auxio.util.logD
 

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

@@ -37,9 +37,9 @@ import org.oxycblt.auxio.music.Music
 import org.oxycblt.auxio.music.MusicMode
 import org.oxycblt.auxio.music.MusicParent
 import org.oxycblt.auxio.music.Playlist
+import org.oxycblt.auxio.navigation.NavigationViewModel
 import org.oxycblt.auxio.playback.PlaybackViewModel
 import org.oxycblt.auxio.playback.formatDurationMs
-import org.oxycblt.auxio.ui.NavigationViewModel
 import org.oxycblt.auxio.util.collectImmediately
 import org.oxycblt.auxio.util.logD
 

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

@@ -40,10 +40,10 @@ import org.oxycblt.auxio.music.Music
 import org.oxycblt.auxio.music.MusicMode
 import org.oxycblt.auxio.music.MusicParent
 import org.oxycblt.auxio.music.Song
+import org.oxycblt.auxio.navigation.NavigationViewModel
 import org.oxycblt.auxio.playback.PlaybackViewModel
 import org.oxycblt.auxio.playback.formatDurationMs
 import org.oxycblt.auxio.playback.secsToMs
-import org.oxycblt.auxio.ui.NavigationViewModel
 import org.oxycblt.auxio.util.collectImmediately
 
 /**

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

@@ -29,8 +29,8 @@ import org.oxycblt.auxio.MainFragmentDirections
 import org.oxycblt.auxio.R
 import org.oxycblt.auxio.list.selection.SelectionFragment
 import org.oxycblt.auxio.music.*
-import org.oxycblt.auxio.ui.MainNavigationAction
+import org.oxycblt.auxio.navigation.MainNavigationAction
-import org.oxycblt.auxio.ui.NavigationViewModel
+import org.oxycblt.auxio.navigation.NavigationViewModel
 import org.oxycblt.auxio.util.logD
 import org.oxycblt.auxio.util.showToast
 

app/src/main/java/org/oxycblt/auxio/navigation/MainNavigationAction.kt

@@ -0,0 +1,44 @@
+/*
+ * Copyright (c) 2023 Auxio Project
+ * MainNavigationAction.kt is part of Auxio.
+ *
+ * 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.navigation
+
+import androidx.navigation.NavDirections
+
+/**
+ * Represents the possible actions within the main navigation graph. This can be used with
+ * [NavigationViewModel] to initiate navigation in the main navigation graph from anywhere in the
+ * app, including outside the main navigation graph.
+ *
+ * @author Alexander Capehart (OxygenCobalt)
+ */
+sealed class MainNavigationAction {
+    /** Expand the playback panel. */
+    object OpenPlaybackPanel : MainNavigationAction()
+
+    /** Collapse the playback bottom sheet. */
+    object ClosePlaybackPanel : MainNavigationAction()
+
+    /**
+     * Navigate to the given [NavDirections].
+     *
+     * @param directions The [NavDirections] to navigate to. Assumed to be part of the main
+     *   navigation graph.
+     */
+    data class Directions(val directions: NavDirections) : MainNavigationAction()
+}

app/src/main/java/org/oxycblt/auxio/navigation/NavigationViewModel.kt

@@ -16,10 +16,9 @@
  * along with this program.  If not, see <https://www.gnu.org/licenses/>.
  */
  
-package org.oxycblt.auxio.ui
+package org.oxycblt.auxio.navigation
 
 import androidx.lifecycle.ViewModel
-import androidx.navigation.NavDirections
 import org.oxycblt.auxio.music.Album
 import org.oxycblt.auxio.music.Artist
 import org.oxycblt.auxio.music.Music
@@ -28,7 +27,13 @@ import org.oxycblt.auxio.util.Event
 import org.oxycblt.auxio.util.MutableEvent
 import org.oxycblt.auxio.util.logD
 
-/** A [ViewModel] that handles complicated navigation functionality. */
+/**
+ * A [ViewModel] that handles complicated navigation functionality.
+ *
+ * @author Alexander Capehart (OxygenCobalt)
+ *
+ * TODO: This whole system is very jankily designed, perhaps it's time for a refactor?
+ */
 class NavigationViewModel : ViewModel() {
     private val _mainNavigationAction = MutableEvent<MainNavigationAction>()
     /**
@@ -118,26 +123,3 @@ class NavigationViewModel : ViewModel() {
         }
     }
 }
-
-/**
- * Represents the possible actions within the main navigation graph. This can be used with
- * [NavigationViewModel] to initiate navigation in the main navigation graph from anywhere in the
- * app, including outside the main navigation graph.
- *
- * @author Alexander Capehart (OxygenCobalt)
- */
-sealed class MainNavigationAction {
-    /** Expand the playback panel. */
-    object OpenPlaybackPanel : MainNavigationAction()
-
-    /** Collapse the playback bottom sheet. */
-    object ClosePlaybackPanel : MainNavigationAction()
-
-    /**
-     * Navigate to the given [NavDirections].
-     *
-     * @param directions The [NavDirections] to navigate to. Assumed to be part of the main
-     *   navigation graph.
-     */
-    data class Directions(val directions: NavDirections) : MainNavigationAction()
-}

app/src/main/java/org/oxycblt/auxio/navigation/picker/ArtistNavigationPickerDialog.kt

@@ -16,32 +16,41 @@
  * along with this program.  If not, see <https://www.gnu.org/licenses/>.
  */
  
-package org.oxycblt.auxio.picker
+package org.oxycblt.auxio.navigation.picker
 
-import android.os.Bundle
 import androidx.fragment.app.activityViewModels
+import androidx.fragment.app.viewModels
 import androidx.navigation.fragment.navArgs
 import androidx.recyclerview.widget.RecyclerView
 import dagger.hilt.android.AndroidEntryPoint
-import org.oxycblt.auxio.databinding.DialogMusicPickerBinding
+import kotlinx.coroutines.flow.StateFlow
+import org.oxycblt.auxio.R
 import org.oxycblt.auxio.music.Artist
-import org.oxycblt.auxio.ui.NavigationViewModel
+import org.oxycblt.auxio.navigation.NavigationViewModel
+import org.oxycblt.auxio.picker.PickerChoices
+import org.oxycblt.auxio.picker.PickerDialogFragment
 
 /**
- * An [ArtistPickerDialog] intended for when [Artist] navigation is ambiguous.
+ * A [PickerDialogFragment] intended for when [Artist] navigation is ambiguous.
  *
  * @author Alexander Capehart (OxygenCobalt)
  */
 @AndroidEntryPoint
-class ArtistNavigationPickerDialog : ArtistPickerDialog() {
+class ArtistNavigationPickerDialog : PickerDialogFragment<Artist>() {
     private val navModel: NavigationViewModel by activityViewModels()
+    private val pickerModel: NavigationPickerViewModel by viewModels()
     // Information about what Song to show choices for is initially within the navigation arguments
     // as UIDs, as that is the only safe way to parcel a Song.
     private val args: ArtistNavigationPickerDialogArgs by navArgs()
 
-    override fun onBindingCreated(binding: DialogMusicPickerBinding, savedInstanceState: Bundle?) {
+    override val titleRes: Int
-        pickerModel.setItemUid(args.itemUid)
+        get() = R.string.lbl_artists
-        super.onBindingCreated(binding, savedInstanceState)
+
+    override val pickerChoices: StateFlow<PickerChoices<Artist>?>
+        get() = pickerModel.currentArtistChoices
+
+    override fun initChoices() {
+        pickerModel.setArtistChoiceUid(args.artistUid)
     }
 
     override fun onClick(item: Artist, viewHolder: RecyclerView.ViewHolder) {

app/src/main/java/org/oxycblt/auxio/navigation/picker/NavigationPickerViewModel.kt

@@ -0,0 +1,93 @@
+/*
+ * Copyright (c) 2023 Auxio Project
+ * NavigationPickerViewModel.kt is part of Auxio.
+ *
+ * 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.navigation.picker
+
+import androidx.lifecycle.ViewModel
+import dagger.hilt.android.lifecycle.HiltViewModel
+import javax.inject.Inject
+import kotlinx.coroutines.flow.MutableStateFlow
+import kotlinx.coroutines.flow.StateFlow
+import org.oxycblt.auxio.music.*
+import org.oxycblt.auxio.picker.PickerChoices
+
+/**
+ * A [ViewModel] that stores the current information required for [ArtistNavigationPickerDialog].
+ *
+ * @author Alexander Capehart (OxygenCobalt)
+ */
+@HiltViewModel
+class NavigationPickerViewModel @Inject constructor(private val musicRepository: MusicRepository) :
+    ViewModel(), MusicRepository.UpdateListener {
+    private val _currentArtistChoices = MutableStateFlow<ArtistNavigationChoices?>(null)
+    /** The current set of [Artist] choices to show in the picker, or null if to show nothing. */
+    val currentArtistChoices: StateFlow<PickerChoices<Artist>?>
+        get() = _currentArtistChoices
+
+    init {
+        musicRepository.addUpdateListener(this)
+    }
+
+    override fun onMusicChanges(changes: MusicRepository.Changes) {
+        if (!changes.deviceLibrary) return
+        val deviceLibrary = musicRepository.deviceLibrary ?: return
+        // Need to sanitize different items depending on the current set of choices.
+        _currentArtistChoices.value =
+            when (val choices = _currentArtistChoices.value) {
+                is ArtistNavigationChoices.FromSong ->
+                    deviceLibrary.findSong(choices.song.uid)?.let {
+                        ArtistNavigationChoices.FromSong(it)
+                    }
+                is ArtistNavigationChoices.FromAlbum ->
+                    deviceLibrary.findAlbum(choices.album.uid)?.let {
+                        ArtistNavigationChoices.FromAlbum(it)
+                    }
+                else -> null
+            }
+    }
+
+    override fun onCleared() {
+        super.onCleared()
+        musicRepository.removeUpdateListener(this)
+    }
+
+    /**
+     * Set the [Music.UID] of the item to show artist choices for.
+     *
+     * @param uid The [Music.UID] of the item to show. Must be a [Song] or [Album].
+     */
+    fun setArtistChoiceUid(uid: Music.UID) {
+        // Support Songs and Albums, which have parent artists.
+        _currentArtistChoices.value =
+            when (val music = musicRepository.find(uid)) {
+                is Song -> ArtistNavigationChoices.FromSong(music)
+                is Album -> ArtistNavigationChoices.FromAlbum(music)
+                else -> null
+            }
+    }
+
+    private sealed interface ArtistNavigationChoices : PickerChoices<Artist> {
+        data class FromSong(val song: Song) : ArtistNavigationChoices {
+            override val choices = song.artists
+        }
+
+        data class FromAlbum(val album: Album) : ArtistNavigationChoices {
+            override val choices = album.artists
+        }
+    }
+}

app/src/main/java/org/oxycblt/auxio/picker/ArtistChoiceAdapter.kt

@@ -1,90 +0,0 @@
-/*
- * Copyright (c) 2022 Auxio Project
- * ArtistChoiceAdapter.kt is part of Auxio.
- *
- * 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.picker
-
-import android.view.View
-import android.view.ViewGroup
-import androidx.recyclerview.widget.RecyclerView
-import org.oxycblt.auxio.databinding.ItemPickerChoiceBinding
-import org.oxycblt.auxio.list.ClickableListListener
-import org.oxycblt.auxio.list.recycler.DialogRecyclerView
-import org.oxycblt.auxio.music.Artist
-import org.oxycblt.auxio.util.context
-import org.oxycblt.auxio.util.inflater
-
-/**
- * An [RecyclerView.Adapter] that displays a list of [Artist] choices.
- *
- * @param listener A [ClickableListListener] to bind interactions to.
- * @author OxygenCobalt.
- */
-class ArtistChoiceAdapter(private val listener: ClickableListListener<Artist>) :
-    RecyclerView.Adapter<ArtistChoiceViewHolder>() {
-    private var artists = listOf<Artist>()
-
-    override fun getItemCount() = artists.size
-
-    override fun onCreateViewHolder(parent: ViewGroup, viewType: Int) =
-        ArtistChoiceViewHolder.from(parent)
-
-    override fun onBindViewHolder(holder: ArtistChoiceViewHolder, position: Int) =
-        holder.bind(artists[position], listener)
-
-    /**
-     * Immediately update the [Artist] choices.
-     *
-     * @param newArtists The new [Artist]s to show.
-     */
-    fun submitList(newArtists: List<Artist>) {
-        if (newArtists != artists) {
-            artists = newArtists
-            @Suppress("NotifyDataSetChanged") notifyDataSetChanged()
-        }
-    }
-}
-
-/**
- * A [DialogRecyclerView.ViewHolder] that displays a smaller variant of a typical [Artist] item, for
- * use with [ArtistChoiceAdapter]. Use [from] to create an instance.
- */
-class ArtistChoiceViewHolder(private val binding: ItemPickerChoiceBinding) :
-    DialogRecyclerView.ViewHolder(binding.root) {
-    /**
-     * Bind new data to this instance.
-     *
-     * @param artist The new [Artist] to bind.
-     * @param listener A [ClickableListListener] to bind interactions to.
-     */
-    fun bind(artist: Artist, listener: ClickableListListener<Artist>) {
-        listener.bind(artist, this)
-        binding.pickerImage.bind(artist)
-        binding.pickerName.text = artist.resolveName(binding.context)
-    }
-
-    companion object {
-        /**
-         * Create a new instance.
-         *
-         * @param parent The parent to inflate this instance from.
-         * @return A new instance.
-         */
-        fun from(parent: View) =
-            ArtistChoiceViewHolder(ItemPickerChoiceBinding.inflate(parent.context.inflater))
-    }
-}

app/src/main/java/org/oxycblt/auxio/picker/ChoiceAdapter.kt

@@ -0,0 +1,87 @@
+/*
+ * Copyright (c) 2023 Auxio Project
+ * ChoiceAdapter.kt is part of Auxio.
+ *
+ * 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.picker
+
+import android.view.View
+import android.view.ViewGroup
+import androidx.recyclerview.widget.RecyclerView
+import org.oxycblt.auxio.databinding.ItemPickerChoiceBinding
+import org.oxycblt.auxio.list.ClickableListListener
+import org.oxycblt.auxio.list.adapter.FlexibleListAdapter
+import org.oxycblt.auxio.list.adapter.SimpleDiffCallback
+import org.oxycblt.auxio.list.recycler.DialogRecyclerView
+import org.oxycblt.auxio.music.*
+import org.oxycblt.auxio.util.context
+import org.oxycblt.auxio.util.inflater
+
+/** A [RecyclerView.Adapter] that shows a list */
+class ChoiceAdapter<T : Music>(private val listener: ClickableListListener<T>) :
+    FlexibleListAdapter<T, ChoiceViewHolder<T>>(ChoiceViewHolder.diffCallback()) {
+    override fun onCreateViewHolder(parent: ViewGroup, viewType: Int) =
+        ChoiceViewHolder.from<T>(parent)
+
+    override fun onBindViewHolder(holder: ChoiceViewHolder<T>, position: Int) =
+        holder.bind(getItem(position), listener)
+}
+
+/**
+ * A [DialogRecyclerView.ViewHolder] that displays a smaller variant of a typical [T] item, for use
+ * with [ChoiceAdapter]. Use [from] to create an instance.
+ */
+class ChoiceViewHolder<T : Music>
+private constructor(private val binding: ItemPickerChoiceBinding) :
+    DialogRecyclerView.ViewHolder(binding.root) {
+    /**
+     * Bind new data to this instance.
+     *
+     * @param music The new [T] to bind.
+     * @param listener A [ClickableListListener] to bind interactions to.
+     */
+    fun bind(music: T, listener: ClickableListListener<T>) {
+        listener.bind(music, this)
+        // ImageGroup is not generic, so we must downcast to specific types for now.
+        when (music) {
+            is Song -> binding.pickerImage.bind(music)
+            is Album -> binding.pickerImage.bind(music)
+            is Artist -> binding.pickerImage.bind(music)
+            is Genre -> binding.pickerImage.bind(music)
+            is Playlist -> binding.pickerImage.bind(music)
+        }
+        binding.pickerName.text = music.resolveName(binding.context)
+    }
+
+    companion object {
+
+        /**
+         * Create a new instance.
+         *
+         * @param parent The parent to inflate this instance from.
+         * @return A new instance.
+         */
+        fun <T : Music> from(parent: View) =
+            ChoiceViewHolder<T>(ItemPickerChoiceBinding.inflate(parent.context.inflater))
+
+        /** Get a comparator that can be used with DiffUtil. */
+        fun <T : Music> diffCallback() =
+            object : SimpleDiffCallback<T>() {
+                override fun areContentsTheSame(oldItem: T, newItem: T) =
+                    oldItem.rawName == newItem.rawName
+            }
+    }
+}

app/src/main/java/org/oxycblt/auxio/picker/GenreChoiceAdapter.kt

@@ -1,90 +0,0 @@
-/*
- * Copyright (c) 2022 Auxio Project
- * GenreChoiceAdapter.kt is part of Auxio.
- *
- * 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.picker
-
-import android.view.View
-import android.view.ViewGroup
-import androidx.recyclerview.widget.RecyclerView
-import org.oxycblt.auxio.databinding.ItemPickerChoiceBinding
-import org.oxycblt.auxio.list.ClickableListListener
-import org.oxycblt.auxio.list.recycler.DialogRecyclerView
-import org.oxycblt.auxio.music.Genre
-import org.oxycblt.auxio.util.context
-import org.oxycblt.auxio.util.inflater
-
-/**
- * An [RecyclerView.Adapter] that displays a list of [Genre] choices.
- *
- * @param listener A [ClickableListListener] to bind interactions to.
- * @author OxygenCobalt.
- */
-class GenreChoiceAdapter(private val listener: ClickableListListener<Genre>) :
-    RecyclerView.Adapter<GenreChoiceViewHolder>() {
-    private var genres = listOf<Genre>()
-
-    override fun getItemCount() = genres.size
-
-    override fun onCreateViewHolder(parent: ViewGroup, viewType: Int) =
-        GenreChoiceViewHolder.from(parent)
-
-    override fun onBindViewHolder(holder: GenreChoiceViewHolder, position: Int) =
-        holder.bind(genres[position], listener)
-
-    /**
-     * Immediately update the [Genre] choices.
-     *
-     * @param newGenres The new [Genre]s to show.
-     */
-    fun submitList(newGenres: List<Genre>) {
-        if (newGenres != genres) {
-            genres = newGenres
-            @Suppress("NotifyDataSetChanged") notifyDataSetChanged()
-        }
-    }
-}
-
-/**
- * A [DialogRecyclerView.ViewHolder] that displays a smaller variant of a typical [Genre] item, for
- * use with [GenreChoiceAdapter]. Use [from] to create an instance.
- */
-class GenreChoiceViewHolder(private val binding: ItemPickerChoiceBinding) :
-    DialogRecyclerView.ViewHolder(binding.root) {
-    /**
-     * Bind new data to this instance.
-     *
-     * @param genre The new [Genre] to bind.
-     * @param listener A [ClickableListListener] to bind interactions to.
-     */
-    fun bind(genre: Genre, listener: ClickableListListener<Genre>) {
-        listener.bind(genre, this)
-        binding.pickerImage.bind(genre)
-        binding.pickerName.text = genre.resolveName(binding.context)
-    }
-
-    companion object {
-        /**
-         * Create a new instance.
-         *
-         * @param parent The parent to inflate this instance from.
-         * @return A new instance.
-         */
-        fun from(parent: View) =
-            GenreChoiceViewHolder(ItemPickerChoiceBinding.inflate(parent.context.inflater))
-    }
-}

app/src/main/java/org/oxycblt/auxio/picker/PickerChoices.kt

@@ -0,0 +1,31 @@
+/*
+ * Copyright (c) 2023 Auxio Project
+ * PickerChoices.kt is part of Auxio.
+ *
+ * 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.picker
+
+import org.oxycblt.auxio.music.Music
+
+/**
+ * Represents a list of [Music] to show in a picker UI.
+ *
+ * @author Alexander Capehart (OxygenCobalt)
+ */
+interface PickerChoices<T : Music> {
+    /** The list of choices to show. */
+    val choices: List<T>
+}

app/src/main/java/org/oxycblt/auxio/picker/PickerDialogFragment.kt

@@ -1,6 +1,6 @@
 /*
- * Copyright (c) 2022 Auxio Project
+ * Copyright (c) 2023 Auxio Project
- * ArtistPickerDialog.kt is part of Auxio.
+ * PickerDialogFragment.kt is part of Auxio.
  *
  * 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
@@ -21,45 +21,53 @@ package org.oxycblt.auxio.picker
 import android.os.Bundle
 import android.view.LayoutInflater
 import androidx.appcompat.app.AlertDialog
-import androidx.fragment.app.viewModels
 import androidx.navigation.fragment.findNavController
 import androidx.recyclerview.widget.RecyclerView
-import dagger.hilt.android.AndroidEntryPoint
+import kotlinx.coroutines.flow.StateFlow
 import org.oxycblt.auxio.R
 import org.oxycblt.auxio.databinding.DialogMusicPickerBinding
 import org.oxycblt.auxio.list.ClickableListListener
-import org.oxycblt.auxio.music.Artist
+import org.oxycblt.auxio.list.adapter.UpdateInstructions
+import org.oxycblt.auxio.music.Music
 import org.oxycblt.auxio.ui.ViewBindingDialogFragment
 import org.oxycblt.auxio.util.collectImmediately
 
 /**
- * The base class for dialogs that implements common behavior across all [Artist] pickers. These are
+ * A [ViewBindingDialogFragment] that acts as the base for a "picker" UI, shown when a given choice
- * shown whenever what to do with an item's [Artist] is ambiguous, as there are multiple [Artist]'s
+ * is ambiguous.
- * to choose from.
  *
  * @author Alexander Capehart (OxygenCobalt)
  */
-@AndroidEntryPoint
+abstract class PickerDialogFragment<T : Music> :
-abstract class ArtistPickerDialog :
+    ViewBindingDialogFragment<DialogMusicPickerBinding>(), ClickableListListener<T> {
-    ViewBindingDialogFragment<DialogMusicPickerBinding>(), ClickableListListener<Artist> {
-    protected val pickerModel: PickerViewModel by viewModels()
     // Okay to leak this since the Listener will not be called until after initialization.
-    private val artistAdapter = ArtistChoiceAdapter(@Suppress("LeakingThis") this)
+    private val choiceAdapter = ChoiceAdapter(@Suppress("LeakingThis") this)
+
+    /** The string resource to use in the dialog title. */
+    abstract val titleRes: Int
+    /** The [StateFlow] of choices to show in the picker. */
+    abstract val pickerChoices: StateFlow<PickerChoices<T>?>
+    /** Called when the choice list should be initialized from the stored arguments. */
+    abstract fun initChoices()
 
     override fun onCreateBinding(inflater: LayoutInflater) =
         DialogMusicPickerBinding.inflate(inflater)
 
     override fun onConfigDialog(builder: AlertDialog.Builder) {
-        builder.setTitle(R.string.lbl_artists).setNegativeButton(R.string.lbl_cancel, null)
+        builder.setTitle(titleRes).setNegativeButton(R.string.lbl_cancel, null)
     }
 
     override fun onBindingCreated(binding: DialogMusicPickerBinding, savedInstanceState: Bundle?) {
-        binding.pickerRecycler.adapter = artistAdapter
+        binding.pickerRecycler.apply {
+            itemAnimator = null
+            adapter = choiceAdapter
+        }
 
-        collectImmediately(pickerModel.artistChoices) { artists ->
+        initChoices()
-            if (artists.isNotEmpty()) {
+        collectImmediately(pickerChoices) { item ->
-                // Make sure the artist choices align with any changes in the music library.
+            if (item != null) {
-                artistAdapter.submitList(artists)
+                // Make sure the choices align with any changes in the music library.
+                choiceAdapter.update(item.choices, UpdateInstructions.Diff)
             } else {
                 // Not showing any choices, navigate up.
                 findNavController().navigateUp()
@@ -71,7 +79,7 @@ abstract class ArtistPickerDialog :
         binding.pickerRecycler.adapter = null
     }
 
-    override fun onClick(item: Artist, viewHolder: RecyclerView.ViewHolder) {
+    override fun onClick(item: T, viewHolder: RecyclerView.ViewHolder) {
         findNavController().navigateUp()
     }
 }

app/src/main/java/org/oxycblt/auxio/picker/PickerViewModel.kt

@@ -1,87 +0,0 @@
-/*
- * Copyright (c) 2022 Auxio Project
- * PickerViewModel.kt is part of Auxio.
- *
- * 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.picker
-
-import androidx.lifecycle.ViewModel
-import dagger.hilt.android.lifecycle.HiltViewModel
-import javax.inject.Inject
-import kotlinx.coroutines.flow.MutableStateFlow
-import kotlinx.coroutines.flow.StateFlow
-import org.oxycblt.auxio.music.*
-
-/**
- * a [ViewModel] that manages the current music picker state. Make it so that the dialogs just
- * contain the music themselves and then exit if the library changes.
- *
- * @author Alexander Capehart (OxygenCobalt)
- */
-@HiltViewModel
-class PickerViewModel @Inject constructor(private val musicRepository: MusicRepository) :
-    ViewModel(), MusicRepository.UpdateListener {
-
-    private val _currentItem = MutableStateFlow<Music?>(null)
-    /** The current item whose artists should be shown in the picker. Null if there is no item. */
-    val currentItem: StateFlow<Music?>
-        get() = _currentItem
-
-    private val _artistChoices = MutableStateFlow<List<Artist>>(listOf())
-    /** The current [Artist] choices. Empty if no item is shown in the picker. */
-    val artistChoices: StateFlow<List<Artist>>
-        get() = _artistChoices
-
-    private val _genreChoices = MutableStateFlow<List<Genre>>(listOf())
-    /** The current [Genre] choices. Empty if no item is shown in the picker. */
-    val genreChoices: StateFlow<List<Genre>>
-        get() = _genreChoices
-
-    init {
-        musicRepository.addUpdateListener(this)
-    }
-
-    override fun onCleared() {
-        musicRepository.removeUpdateListener(this)
-    }
-
-    override fun onMusicChanges(changes: MusicRepository.Changes) {
-        if (changes.deviceLibrary && musicRepository.deviceLibrary != null) {
-            refreshChoices()
-        }
-    }
-
-    /**
-     * Set a new [currentItem] from it's [Music.UID].
-     *
-     * @param uid The [Music.UID] of the [Song] to update to.
-     */
-    fun setItemUid(uid: Music.UID) {
-        _currentItem.value = musicRepository.find(uid)
-        refreshChoices()
-    }
-
-    private fun refreshChoices() {
-        when (val item = _currentItem.value) {
-            is Song -> {
-                _artistChoices.value = item.artists
-                _genreChoices.value = item.genres
-            }
-            is Album -> _artistChoices.value = item.artists
-            else -> {}
-        }
-    }
-}

app/src/main/java/org/oxycblt/auxio/playback/PlaybackBarFragment.kt

@@ -26,9 +26,9 @@ import org.oxycblt.auxio.R
 import org.oxycblt.auxio.databinding.FragmentPlaybackBarBinding
 import org.oxycblt.auxio.music.Song
 import org.oxycblt.auxio.music.resolveNames
+import org.oxycblt.auxio.navigation.MainNavigationAction
+import org.oxycblt.auxio.navigation.NavigationViewModel
 import org.oxycblt.auxio.playback.state.RepeatMode
-import org.oxycblt.auxio.ui.MainNavigationAction
-import org.oxycblt.auxio.ui.NavigationViewModel
 import org.oxycblt.auxio.ui.ViewBindingFragment
 import org.oxycblt.auxio.util.collectImmediately
 import org.oxycblt.auxio.util.getAttrColorCompat

app/src/main/java/org/oxycblt/auxio/playback/PlaybackPanelFragment.kt

@@ -36,10 +36,10 @@ import org.oxycblt.auxio.databinding.FragmentPlaybackPanelBinding
 import org.oxycblt.auxio.music.MusicParent
 import org.oxycblt.auxio.music.Song
 import org.oxycblt.auxio.music.resolveNames
+import org.oxycblt.auxio.navigation.MainNavigationAction
+import org.oxycblt.auxio.navigation.NavigationViewModel
 import org.oxycblt.auxio.playback.state.RepeatMode
 import org.oxycblt.auxio.playback.ui.StyledSeekBar
-import org.oxycblt.auxio.ui.MainNavigationAction
-import org.oxycblt.auxio.ui.NavigationViewModel
 import org.oxycblt.auxio.ui.ViewBindingFragment
 import org.oxycblt.auxio.util.collectImmediately
 import org.oxycblt.auxio.util.showToast

app/src/main/java/org/oxycblt/auxio/playback/picker/ArtistPlaybackPickerDialog.kt

@@ -16,18 +16,19 @@
  * along with this program.  If not, see <https://www.gnu.org/licenses/>.
  */
  
-package org.oxycblt.auxio.picker
+package org.oxycblt.auxio.playback.picker
 
-import android.os.Bundle
 import androidx.fragment.app.activityViewModels
+import androidx.fragment.app.viewModels
 import androidx.navigation.fragment.navArgs
 import androidx.recyclerview.widget.RecyclerView
 import dagger.hilt.android.AndroidEntryPoint
-import org.oxycblt.auxio.databinding.DialogMusicPickerBinding
+import kotlinx.coroutines.flow.StateFlow
+import org.oxycblt.auxio.R
 import org.oxycblt.auxio.music.Artist
-import org.oxycblt.auxio.music.Song
+import org.oxycblt.auxio.picker.PickerChoices
+import org.oxycblt.auxio.picker.PickerDialogFragment
 import org.oxycblt.auxio.playback.PlaybackViewModel
-import org.oxycblt.auxio.util.requireIs
 import org.oxycblt.auxio.util.unlikelyToBeNull
 
 /**
@@ -36,21 +37,27 @@ import org.oxycblt.auxio.util.unlikelyToBeNull
  * @author Alexander Capehart (OxygenCobalt)
  */
 @AndroidEntryPoint
-class ArtistPlaybackPickerDialog : ArtistPickerDialog() {
+class ArtistPlaybackPickerDialog : PickerDialogFragment<Artist>() {
     private val playbackModel: PlaybackViewModel by activityViewModels()
+    private val pickerModel: PlaybackPickerViewModel by viewModels()
     // Information about what Song to show choices for is initially within the navigation arguments
     // as UIDs, as that is the only safe way to parcel a Song.
     private val args: ArtistPlaybackPickerDialogArgs by navArgs()
 
-    override fun onBindingCreated(binding: DialogMusicPickerBinding, savedInstanceState: Bundle?) {
+    override val titleRes: Int
-        pickerModel.setItemUid(args.itemUid)
+        get() = R.string.lbl_artists
-        super.onBindingCreated(binding, savedInstanceState)
+
+    override val pickerChoices: StateFlow<PickerChoices<Artist>?>
+        get() = pickerModel.currentArtistChoices
+
+    override fun initChoices() {
+        pickerModel.setArtistChoiceUid(args.artistUid)
     }
 
     override fun onClick(item: Artist, viewHolder: RecyclerView.ViewHolder) {
         super.onClick(item, viewHolder)
         // User made a choice, play the given song from that artist.
-        val song = requireIs<Song>(unlikelyToBeNull(pickerModel.currentItem.value))
+        val song = unlikelyToBeNull(pickerModel.currentArtistChoices.value).song
         playbackModel.playFromArtist(song, item)
     }
 }

app/src/main/java/org/oxycblt/auxio/playback/picker/GenrePlaybackPickerDialog.kt

@@ -16,26 +16,20 @@
  * along with this program.  If not, see <https://www.gnu.org/licenses/>.
  */
  
-package org.oxycblt.auxio.picker
+package org.oxycblt.auxio.playback.picker
 
-import android.os.Bundle
-import android.view.LayoutInflater
-import androidx.appcompat.app.AlertDialog
 import androidx.fragment.app.activityViewModels
 import androidx.fragment.app.viewModels
-import androidx.navigation.fragment.findNavController
 import androidx.navigation.fragment.navArgs
 import androidx.recyclerview.widget.RecyclerView
 import dagger.hilt.android.AndroidEntryPoint
+import kotlinx.coroutines.flow.StateFlow
 import org.oxycblt.auxio.R
-import org.oxycblt.auxio.databinding.DialogMusicPickerBinding
-import org.oxycblt.auxio.list.ClickableListListener
 import org.oxycblt.auxio.music.Genre
-import org.oxycblt.auxio.music.Song
+import org.oxycblt.auxio.picker.PickerChoices
+import org.oxycblt.auxio.picker.PickerDialogFragment
 import org.oxycblt.auxio.playback.PlaybackViewModel
 import org.oxycblt.auxio.ui.ViewBindingDialogFragment
-import org.oxycblt.auxio.util.collectImmediately
-import org.oxycblt.auxio.util.requireIs
 import org.oxycblt.auxio.util.unlikelyToBeNull
 
 /**
@@ -44,45 +38,27 @@ import org.oxycblt.auxio.util.unlikelyToBeNull
  * @author Alexander Capehart (OxygenCobalt)
  */
 @AndroidEntryPoint
-class GenrePlaybackPickerDialog :
+class GenrePlaybackPickerDialog : PickerDialogFragment<Genre>() {
-    ViewBindingDialogFragment<DialogMusicPickerBinding>(), ClickableListListener<Genre> {
-    private val pickerModel: PickerViewModel by viewModels()
     private val playbackModel: PlaybackViewModel by activityViewModels()
+    private val pickerModel: PlaybackPickerViewModel by viewModels()
     // Information about what Song to show choices for is initially within the navigation arguments
     // as UIDs, as that is the only safe way to parcel a Song.
     private val args: GenrePlaybackPickerDialogArgs by navArgs()
-    // Okay to leak this since the Listener will not be called until after initialization.
-    private val genreAdapter = GenreChoiceAdapter(@Suppress("LeakingThis") this)
 
-    override fun onCreateBinding(inflater: LayoutInflater) =
+    override val titleRes: Int
-        DialogMusicPickerBinding.inflate(inflater)
+        get() = R.string.lbl_genres
 
-    override fun onConfigDialog(builder: AlertDialog.Builder) {
+    override val pickerChoices: StateFlow<PickerChoices<Genre>?>
-        builder.setTitle(R.string.lbl_genres).setNegativeButton(R.string.lbl_cancel, null)
+        get() = pickerModel.currentGenreChoices
-    }
 
-    override fun onBindingCreated(binding: DialogMusicPickerBinding, savedInstanceState: Bundle?) {
+    override fun initChoices() {
-        binding.pickerRecycler.adapter = genreAdapter
+        pickerModel.setGenreChoiceUid(args.genreUid)
-
-        pickerModel.setItemUid(args.itemUid)
-        collectImmediately(pickerModel.genreChoices) { genres ->
-            if (genres.isNotEmpty()) {
-                // Make sure the genre choices align with any changes in the music library.
-                genreAdapter.submitList(genres)
-            } else {
-                // Not showing any choices, navigate up.
-                findNavController().navigateUp()
-            }
-        }
-    }
-
-    override fun onDestroyBinding(binding: DialogMusicPickerBinding) {
-        binding.pickerRecycler.adapter = null
     }
 
     override fun onClick(item: Genre, viewHolder: RecyclerView.ViewHolder) {
+        super.onClick(item, viewHolder)
         // User made a choice, play the given song from that genre.
-        val song = requireIs<Song>(unlikelyToBeNull(pickerModel.currentItem.value))
+        val song = unlikelyToBeNull(pickerModel.currentGenreChoices.value).song
         playbackModel.playFromGenre(song, item)
     }
 }

app/src/main/java/org/oxycblt/auxio/playback/picker/PlaybackPickerViewModel.kt

@@ -0,0 +1,96 @@
+/*
+ * Copyright (c) 2023 Auxio Project
+ * PlaybackPickerViewModel.kt is part of Auxio.
+ *
+ * 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.playback.picker
+
+import androidx.lifecycle.ViewModel
+import dagger.hilt.android.lifecycle.HiltViewModel
+import javax.inject.Inject
+import kotlinx.coroutines.flow.MutableStateFlow
+import kotlinx.coroutines.flow.StateFlow
+import org.oxycblt.auxio.music.*
+import org.oxycblt.auxio.picker.PickerChoices
+
+/**
+ * A [ViewModel] that stores the choices shown in the playback picker dialogs.
+ *
+ * @author OxygenCobalt (Alexander Capehart)
+ */
+@HiltViewModel
+class PlaybackPickerViewModel @Inject constructor(private val musicRepository: MusicRepository) :
+    ViewModel(), MusicRepository.UpdateListener {
+    private val _currentArtistChoices = MutableStateFlow<ArtistPlaybackChoices?>(null)
+    /** The current set of [Artist] choices to show in the picker, or null if to show nothing. */
+    val currentArtistChoices: StateFlow<ArtistPlaybackChoices?>
+        get() = _currentArtistChoices
+
+    private val _currentGenreChoices = MutableStateFlow<GenrePlaybackChoices?>(null)
+    /** The current set of [Genre] choices to show in the picker, or null if to show nothing. */
+    val currentGenreChoices: StateFlow<GenrePlaybackChoices?>
+        get() = _currentGenreChoices
+
+    init {
+        musicRepository.addUpdateListener(this)
+    }
+
+    override fun onMusicChanges(changes: MusicRepository.Changes) {
+        if (!changes.deviceLibrary) return
+        val deviceLibrary = musicRepository.deviceLibrary ?: return
+        _currentArtistChoices.value =
+            _currentArtistChoices.value?.run {
+                deviceLibrary.findSong(song.uid)?.let { newSong -> ArtistPlaybackChoices(newSong) }
+            }
+        _currentGenreChoices.value =
+            _currentGenreChoices.value?.run {
+                deviceLibrary.findSong(song.uid)?.let { newSong -> GenrePlaybackChoices(newSong) }
+            }
+    }
+
+    override fun onCleared() {
+        super.onCleared()
+        musicRepository.removeUpdateListener(this)
+    }
+
+    /**
+     * Set the [Music.UID] of the item to show [Artist] choices for.
+     *
+     * @param uid The [Music.UID] of the item to show. Must be a [Song].
+     */
+    fun setArtistChoiceUid(uid: Music.UID) {
+        _currentArtistChoices.value =
+            musicRepository.deviceLibrary?.findSong(uid)?.let { ArtistPlaybackChoices(it) }
+    }
+
+    /**
+     * Set the [Music.UID] of the item to show [Genre] choices for.
+     *
+     * @param uid The [Music.UID] of the item to show. Must be a [Song].
+     */
+    fun setGenreChoiceUid(uid: Music.UID) {
+        _currentGenreChoices.value =
+            musicRepository.deviceLibrary?.findSong(uid)?.let { GenrePlaybackChoices(it) }
+    }
+}
+
+data class ArtistPlaybackChoices(val song: Song) : PickerChoices<Artist> {
+    override val choices = song.artists
+}
+
+data class GenrePlaybackChoices(val song: Song) : PickerChoices<Genre> {
+    override val choices = song.genres
+}

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

@@ -37,8 +37,8 @@ import org.oxycblt.auxio.list.Item
 import org.oxycblt.auxio.list.ListFragment
 import org.oxycblt.auxio.list.selection.SelectionViewModel
 import org.oxycblt.auxio.music.*
+import org.oxycblt.auxio.navigation.NavigationViewModel
 import org.oxycblt.auxio.playback.PlaybackViewModel
-import org.oxycblt.auxio.ui.NavigationViewModel
 import org.oxycblt.auxio.util.*
 
 /**

app/src/main/res/navigation/nav_main.xml

@@ -30,31 +30,31 @@
 
     <dialog
         android:id="@+id/artist_playback_picker_dialog"
-        android:name="org.oxycblt.auxio.picker.ArtistPlaybackPickerDialog"
+        android:name="org.oxycblt.auxio.playback.picker.ArtistPlaybackPickerDialog"
         android:label="artist_playback_picker_dialog"
         tools:layout="@layout/dialog_music_picker">
         <argument
-            android:name="itemUid"
+            android:name="artistUid"
             app:argType="org.oxycblt.auxio.music.Music$UID" />
     </dialog>
 
     <dialog
         android:id="@+id/artist_navigation_picker_dialog"
-        android:name="org.oxycblt.auxio.picker.ArtistNavigationPickerDialog"
+        android:name="org.oxycblt.auxio.navigation.picker.ArtistNavigationPickerDialog"
         android:label="artist_navigation_picker_dialog"
         tools:layout="@layout/dialog_music_picker">
         <argument
-            android:name="itemUid"
+            android:name="artistUid"
             app:argType="org.oxycblt.auxio.music.Music$UID" />
     </dialog>
 
     <dialog
         android:id="@+id/genre_playback_picker_dialog"
-        android:name="org.oxycblt.auxio.picker.GenrePlaybackPickerDialog"
+        android:name="org.oxycblt.auxio.playback.picker.GenrePlaybackPickerDialog"
         android:label="genre_playback_picker_dialog"
         tools:layout="@layout/dialog_music_picker">
         <argument
-            android:name="itemUid"
+            android:name="genreUid"
             app:argType="org.oxycblt.auxio.music.Music$UID" />
     </dialog>
 
@@ -64,7 +64,7 @@
         android:label="song_detail_dialog"
         tools:layout="@layout/dialog_song_detail">
         <argument
-            android:name="itemUid"
+            android:name="songUid"
             app:argType="org.oxycblt.auxio.music.Music$UID" />
     </dialog>