playback: re-add play from genre

Re-add the "Play from genre" setting.

It's much easier to implement this now than prior with the picker
framework, so may as well retain consistency.

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

@@ -74,10 +74,9 @@ class AuxioApp : Application(), ImageLoaderFactory {
             .build()
 
     companion object {
-        /** The ID of the "Shuffle All" shortcut. */
-        const val SHORTCUT_SHUFFLE_ID = "shortcut_shuffle"
-
         /** The [Intent] name for the "Shuffle All" shortcut. */
         const val INTENT_KEY_SHORTCUT_SHUFFLE = BuildConfig.APPLICATION_ID + ".action.SHUFFLE_ALL"
+        /** The ID of the "Shuffle All" shortcut. */
+        private const val SHORTCUT_SHUFFLE_ID = "shortcut_shuffle"
     }
 }

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

@@ -61,6 +61,8 @@ object IntegerTable {
     const val REPEAT_MODE_ALL = 0xA101
     /** RepeatMode.TRACK */
     const val REPEAT_MODE_TRACK = 0xA102
+    /** PlaybackMode.IN_GENRE */
+    const val PLAYBACK_MODE_IN_GENRE = 0xA103
     /** PlaybackMode.IN_ARTIST */
     const val PLAYBACK_MODE_IN_ARTIST = 0xA104
     /** PlaybackMode.IN_ALBUM */

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

@@ -128,9 +128,10 @@ class MainFragment :
         // --- VIEWMODEL SETUP ---
         collect(navModel.mainNavigationAction, ::handleMainNavigation)
         collect(navModel.exploreNavigationItem, ::handleExploreNavigation)
-        collect(navModel.exploreNavigationArtists, ::handleExplorePicker)
+        collect(navModel.exploreArtistNavigationItem, ::handleArtistNavigationPicker)
         collectImmediately(playbackModel.song, ::updateSong)
-        collect(playbackModel.artistPlaybackPickerSong, ::handlePlaybackArtistPicker)
+        collect(playbackModel.artistPickerSong, ::handlePlaybackArtistPicker)
+        collect(playbackModel.genrePickerSong, ::handlePlaybackGenrePicker)
     }
 
     override fun onStart() {
@@ -278,13 +279,11 @@ class MainFragment :
         }
     }
 
-    private fun handleExplorePicker(items: List<Artist>?) {
+    private fun handleArtistNavigationPicker(item: Music?) {
-        if (items != null) {
+        if (item != null) {
-            // Navigate to the analogous artist picker dialog.
             navModel.mainNavigateTo(
                 MainNavigationAction.Directions(
-                    MainFragmentDirections.actionPickNavigationArtist(
+                    MainFragmentDirections.actionPickNavigationArtist(item.uid)))
-                        items.map { it.uid }.toTypedArray())))
             navModel.finishExploreNavigation()
         }
     }
@@ -299,7 +298,6 @@ class MainFragment :
 
     private fun handlePlaybackArtistPicker(song: Song?) {
         if (song != null) {
-            // Navigate to the analogous artist picker dialog.
             navModel.mainNavigateTo(
                 MainNavigationAction.Directions(
                     MainFragmentDirections.actionPickPlaybackArtist(song.uid)))
@@ -307,6 +305,15 @@ class MainFragment :
         }
     }
 
+    private fun handlePlaybackGenrePicker(song: Song?) {
+        if (song != null) {
+            navModel.mainNavigateTo(
+                MainNavigationAction.Directions(
+                    MainFragmentDirections.actionPickPlaybackGenre(song.uid)))
+            playbackModel.finishPlaybackArtistPicker()
+        }
+    }
+
     private fun tryExpandSheets() {
         val binding = requireBinding()
         val playbackSheetBehavior =

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

@@ -128,14 +128,14 @@ class AlbumDetailFragment : ListFragment<FragmentDetailBinding>(), AlbumDetailAd
 
     override fun onRealClick(music: Music) {
         check(music is Song) { "Unexpected datatype: ${music::class.java}" }
-        when (val mode = Settings(requireContext()).detailPlaybackMode) {
+        when (Settings(requireContext()).detailPlaybackMode) {
             // "Play from shown item" and "Play from album" functionally have the same
             // behavior since a song can only have one album.
             null,
             MusicMode.ALBUMS -> playbackModel.playFromAlbum(music)
             MusicMode.SONGS -> playbackModel.playFromAll(music)
             MusicMode.ARTISTS -> playbackModel.playFromArtist(music)
-            else -> error("Unexpected playback mode: $mode")
+            MusicMode.GENRES -> playbackModel.playFromGenre(music)
         }
     }
 
@@ -171,7 +171,7 @@ class AlbumDetailFragment : ListFragment<FragmentDetailBinding>(), AlbumDetailAd
     }
 
     override fun onNavigateToParentArtist() {
-        navModel.exploreNavigateTo(unlikelyToBeNull(detailModel.currentAlbum.value).artists)
+        navModel.exploreNavigateToParentArtist(unlikelyToBeNull(detailModel.currentAlbum.value))
     }
 
     private fun updateAlbum(album: Album?) {
@@ -180,7 +180,6 @@ class AlbumDetailFragment : ListFragment<FragmentDetailBinding>(), AlbumDetailAd
             findNavController().navigateUp()
             return
         }
-
         requireBinding().detailToolbar.title = album.resolveName(requireContext())
     }
 

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

@@ -124,16 +124,16 @@ class ArtistDetailFragment : ListFragment<FragmentDetailBinding>(), DetailAdapte
     override fun onRealClick(music: Music) {
         when (music) {
             is Song -> {
-                when (val mode = Settings(requireContext()).detailPlaybackMode) {
+                when (Settings(requireContext()).detailPlaybackMode) {
-                    // "Play from selected item" and "Play from artist" differ, as the latter
+                    // When configured to play from the selected item, we already have an Artist
-                    // actually should show a picker choice in the case of multiple artists.
+                    // to play from.
                     null ->
                         playbackModel.playFromArtist(
                             music, unlikelyToBeNull(detailModel.currentArtist.value))
                     MusicMode.SONGS -> playbackModel.playFromAll(music)
                     MusicMode.ALBUMS -> playbackModel.playFromAlbum(music)
                     MusicMode.ARTISTS -> playbackModel.playFromArtist(music)
-                    else -> error("Unexpected playback mode: $mode")
+                    MusicMode.GENRES -> playbackModel.playFromGenre(music)
                 }
             }
             is Album -> navModel.exploreNavigateTo(music)

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

@@ -124,15 +124,16 @@ class GenreDetailFragment : ListFragment<FragmentDetailBinding>(), DetailAdapter
         when (music) {
             is Artist -> navModel.exploreNavigateTo(music)
             is Song ->
-                when (val mode = Settings(requireContext()).detailPlaybackMode) {
+                when (Settings(requireContext()).detailPlaybackMode) {
-                    // Only way to play from the genre is through "Play from selected item".
+                    // When configured to play from the selected item, we already have a Genre
+                    // to play from.
                     null ->
                         playbackModel.playFromGenre(
                             music, unlikelyToBeNull(detailModel.currentGenre.value))
                     MusicMode.SONGS -> playbackModel.playFromAll(music)
                     MusicMode.ALBUMS -> playbackModel.playFromAlbum(music)
                     MusicMode.ARTISTS -> playbackModel.playFromArtist(music)
-                    else -> error("Unexpected playback mode: $mode")
+                    MusicMode.GENRES -> playbackModel.playFromGenre(music)
                 }
             else -> error("Unexpected datatype: ${music::class.simpleName}")
         }

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

@@ -52,7 +52,7 @@ class SongDetailDialog : ViewBindingDialogFragment<DialogSongDetailBinding>() {
     override fun onBindingCreated(binding: DialogSongDetailBinding, savedInstanceState: Bundle?) {
         super.onBindingCreated(binding, savedInstanceState)
         // DetailViewModel handles most initialization from the navigation argument.
-        detailModel.setSongUid(args.songUid)
+        detailModel.setSongUid(args.itemUid)
         collectImmediately(detailModel.currentSong, ::updateSong)
     }
 

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

@@ -155,9 +155,7 @@ class HomeFragment :
         collect(homeModel.shouldRecreate, ::handleRecreate)
         collectImmediately(homeModel.currentTabMode, ::updateCurrentTab)
         collectImmediately(homeModel.songLists, homeModel.isFastScrolling, ::updateFab)
-
         collectImmediately(musicModel.indexerState, ::updateIndexerState)
-
         collect(navModel.exploreNavigationItem, ::handleNavigation)
         collectImmediately(selectionModel.selected, ::updateSelection)
     }
@@ -484,9 +482,7 @@ class HomeFragment :
         fragmentManager: FragmentManager,
         lifecycleOwner: LifecycleOwner
     ) : FragmentStateAdapter(fragmentManager, lifecycleOwner.lifecycle) {
-
         override fun getItemCount() = tabs.size
-
         override fun createFragment(position: Int): Fragment =
             when (tabs[position]) {
                 MusicMode.SONGS -> SongListFragment()

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

@@ -132,11 +132,11 @@ class SongListFragment :
 
     override fun onRealClick(music: Music) {
         check(music is Song) { "Unexpected datatype: ${music::class.java}" }
-        when (val mode = Settings(requireContext()).libPlaybackMode) {
+        when (Settings(requireContext()).libPlaybackMode) {
             MusicMode.SONGS -> playbackModel.playFromAll(music)
             MusicMode.ALBUMS -> playbackModel.playFromAlbum(music)
             MusicMode.ARTISTS -> playbackModel.playFromArtist(music)
-            else -> error("Unexpected playback mode: $mode")
+            MusicMode.GENRES -> playbackModel.playFromGenre(music)
         }
     }
 

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

@@ -90,7 +90,7 @@ abstract class ListFragment<VB : ViewBinding> : SelectionFragment<VB>(), Selecta
                     requireContext().showToast(R.string.lng_queue_added)
                 }
                 R.id.action_go_artist -> {
-                    navModel.exploreNavigateTo(song.artists)
+                    navModel.exploreNavigateToParentArtist(song)
                 }
                 R.id.action_go_album -> {
                     navModel.exploreNavigateTo(song.album)
@@ -134,7 +134,7 @@ abstract class ListFragment<VB : ViewBinding> : SelectionFragment<VB>(), Selecta
                     requireContext().showToast(R.string.lng_queue_added)
                 }
                 R.id.action_go_artist -> {
-                    navModel.exploreNavigateTo(album.artists)
+                    navModel.exploreNavigateToParentArtist(album)
                 }
                 else -> {
                     error("Unexpected menu item selected")

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

@@ -28,7 +28,7 @@ import org.oxycblt.auxio.util.context
 import org.oxycblt.auxio.util.inflater
 
 /**
- * An adapter responsible for showing a list of [Artist] choices in [ArtistPickerDialog].
+ * An [RecyclerView.Adapter] that displays a list of [Artist] choices.
  * @param listener A [ClickableListListener] to bind interactions to.
  * @author OxygenCobalt.
  */

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

@@ -31,12 +31,12 @@ import org.oxycblt.auxio.ui.NavigationViewModel
  */
 class ArtistNavigationPickerDialog : ArtistPickerDialog() {
     private val navModel: NavigationViewModel by activityViewModels()
-    // Information about what artists to display is initially within the navigation arguments
+    // Information about what Song to show choices for is initially within the navigation arguments
-    // as a list of UIDs, as that is the only safe way to parcel an artist.
+    // 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?) {
-        pickerModel.setArtistUids(args.artistUids)
+        pickerModel.setItemUid(args.itemUid)
         super.onBindingCreated(binding, savedInstanceState)
     }
 

app/src/main/java/org/oxycblt/auxio/music/picker/ArtistPickerDialog.kt

@@ -52,11 +52,9 @@ abstract class ArtistPickerDialog :
     override fun onBindingCreated(binding: DialogMusicPickerBinding, savedInstanceState: Bundle?) {
         binding.pickerRecycler.adapter = artistAdapter
 
-        collectImmediately(pickerModel.currentArtists) { artists ->
+        collectImmediately(pickerModel.artistChoices) { artists ->
-            if (!artists.isNullOrEmpty()) {
+            if (artists.isNotEmpty()) {
                 // Make sure the artist choices align with any changes in the music library.
-                // TODO: I really don't think it makes sense to do this. I'd imagine it would
-                //  be more productive to just exit this dialog rather than try to update it.
                 artistAdapter.submitList(artists)
             } else {
                 // Not showing any choices, navigate up.

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

@@ -22,6 +22,7 @@ import androidx.navigation.fragment.navArgs
 import org.oxycblt.auxio.databinding.DialogMusicPickerBinding
 import org.oxycblt.auxio.list.Item
 import org.oxycblt.auxio.music.Artist
+import org.oxycblt.auxio.music.Song
 import org.oxycblt.auxio.playback.PlaybackViewModel
 import org.oxycblt.auxio.util.androidActivityViewModels
 
@@ -31,19 +32,21 @@ import org.oxycblt.auxio.util.androidActivityViewModels
  */
 class ArtistPlaybackPickerDialog : ArtistPickerDialog() {
     private val playbackModel: PlaybackViewModel by androidActivityViewModels()
-    // Information about what artists to display is initially within the navigation arguments
+    // Information about what Song to show choices for is initially within the navigation arguments
-    // as a list of UIDs, as that is the only safe way to parcel an artist.
+    // 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?) {
-        pickerModel.setSongUid(args.songUid)
+        pickerModel.setItemUid(args.itemUid)
         super.onBindingCreated(binding, savedInstanceState)
     }
 
     override fun onClick(item: Item) {
         super.onClick(item)
-        check(item is Artist) { "Unexpected datatype: ${item::class.simpleName}" }
         // User made a choice, play the given song from that artist.
-        pickerModel.currentSong.value?.let { song -> playbackModel.playFromArtist(song, item) }
+        check(item is Artist) { "Unexpected datatype: ${item::class.simpleName}" }
+        val song = pickerModel.currentItem.value
+        check(song is Song) { "Unexpected datatype: ${item::class.simpleName}" }
+        playbackModel.playFromArtist(song, item)
     }
 }

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

@@ -0,0 +1,68 @@
+package org.oxycblt.auxio.music.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) :
+    RecyclerView.Adapter<GenreChoiceViewHolder>() {
+    private var genres = listOf<Genre>()
+
+    override fun getItemCount() = genres.size
+
+    override fun onCreateViewHolder(parent: ViewGroup, viewType: Int) =
+        GenreChoiceViewHolder.new(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 [new] 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) {
+        binding.root.setOnClickListener { listener.onClick(genre) }
+        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 new(parent: View) =
+            GenreChoiceViewHolder(ItemPickerChoiceBinding.inflate(parent.context.inflater))
+    }
+}

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

@@ -0,0 +1,66 @@
+package org.oxycblt.auxio.music.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.navigation.fragment.navArgs
+import org.oxycblt.auxio.R
+import org.oxycblt.auxio.databinding.DialogMusicPickerBinding
+import org.oxycblt.auxio.list.ClickableListListener
+import org.oxycblt.auxio.list.Item
+import org.oxycblt.auxio.music.Genre
+import org.oxycblt.auxio.music.Song
+import org.oxycblt.auxio.playback.PlaybackViewModel
+import org.oxycblt.auxio.ui.ViewBindingDialogFragment
+import org.oxycblt.auxio.util.androidActivityViewModels
+import org.oxycblt.auxio.util.collectImmediately
+
+/**
+ * A picker [ViewBindingDialogFragment] intended for when [Genre] playback is ambiguous.
+ * @author Alexander Capehart (OxygenCobalt)
+ */
+class GenrePlaybackPickerDialog : ViewBindingDialogFragment<DialogMusicPickerBinding>(), ClickableListListener {
+    private val pickerModel: PickerViewModel by viewModels()
+    private val playbackModel: PlaybackViewModel by androidActivityViewModels()
+    // 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) =
+        DialogMusicPickerBinding.inflate(inflater)
+
+    override fun onConfigDialog(builder: AlertDialog.Builder) {
+        builder.setTitle(R.string.lbl_genres).setNegativeButton(R.string.lbl_cancel, null)
+    }
+
+    override fun onBindingCreated(binding: DialogMusicPickerBinding, savedInstanceState: Bundle?) {
+        binding.pickerRecycler.adapter = genreAdapter
+
+        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: Item) {
+        // User made a choice, play the given song from that genre.
+        check(item is Genre) { "Unexpected datatype: ${item::class.simpleName}" }
+        val song = pickerModel.currentItem.value
+        check(song is Song) { "Unexpected datatype: ${item::class.simpleName}" }
+        playbackModel.playFromGenre(song, item)
+    }
+}

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

@@ -20,10 +20,7 @@ package org.oxycblt.auxio.music.picker
 import androidx.lifecycle.ViewModel
 import kotlinx.coroutines.flow.MutableStateFlow
 import kotlinx.coroutines.flow.StateFlow
-import org.oxycblt.auxio.music.Artist
+import org.oxycblt.auxio.music.*
-import org.oxycblt.auxio.music.Music
-import org.oxycblt.auxio.music.MusicStore
-import org.oxycblt.auxio.music.Song
 import org.oxycblt.auxio.util.unlikelyToBeNull
 
 /**
@@ -32,24 +29,21 @@ import org.oxycblt.auxio.util.unlikelyToBeNull
  * @author Alexander Capehart (OxygenCobalt)
  */
 class PickerViewModel : ViewModel(), MusicStore.Callback {
-    // TODO: Refactor
-
     private val musicStore = MusicStore.getInstance()
 
-    private val _currentSong = MutableStateFlow<Song?>(null)
+    private val _currentItem = MutableStateFlow<Music?>(null)
-    /**
+    /** The current item whose artists should be shown in the picker. Null if there is no item. */
-     * The current [Song] whose choices are being shown in the picker. Null if there is no [Song].
+    val currentItem: StateFlow<Music?> get() = _currentItem
-     */
-    val currentSong: StateFlow<Song?>
-        get() = _currentSong
 
-    private val _currentArtists = MutableStateFlow<List<Artist>?>(null)
+    private val _artistChoices = MutableStateFlow<List<Artist>>(listOf())
-    /**
+    /** The current [Artist] choices. Empty if no item is shown in the picker. */
-     * The current [Artist] whose choices are being shown in the picker. Null/Empty if there is
+    val artistChoices: StateFlow<List<Artist>>
-     * none.
+        get() = _artistChoices
-     */
+
-    val currentArtists: StateFlow<List<Artist>?>
+    private val _genreChoices = MutableStateFlow<List<Genre>>(listOf())
-        get() = _currentArtists
+    /** The current [Genre] choices. Empty if no item is shown in the picker. */
+    val genreChoices: StateFlow<List<Genre>>
+        get() = _genreChoices
 
     override fun onCleared() {
         musicStore.removeCallback(this)
@@ -57,37 +51,29 @@ class PickerViewModel : ViewModel(), MusicStore.Callback {
 
     override fun onLibraryChanged(library: MusicStore.Library?) {
         if (library != null) {
-            // If we are showing any item right now, we will need to refresh it (and any information
+            refreshChoices()
-            // related to it) with the new library in order to prevent stale items from appearing
-            // in the UI.
-            val song = _currentSong.value
-            val artists = _currentArtists.value
-            if (song != null) {
-                _currentSong.value = library.sanitize(song)
-                _currentArtists.value = _currentSong.value?.artists
-            } else if (artists != null) {
-                _currentArtists.value = artists.mapNotNull { library.sanitize(it) }
-            }
         }
     }
 
     /**
-     * Set a new [currentSong] from it's [Music.UID].
+     * Set a new [currentItem] from it's [Music.UID].
      * @param uid The [Music.UID] of the [Song] to update to.
      */
-    fun setSongUid(uid: Music.UID) {
+    fun setItemUid(uid: Music.UID) {
         val library = unlikelyToBeNull(musicStore.library)
-        _currentSong.value = library.find(uid)
+        _currentItem.value = library.find(uid)
-        _currentArtists.value = _currentSong.value?.artists
+        refreshChoices()
     }
 
-    /**
+    private fun refreshChoices() {
-     * Set a new [currentArtists] list from a list of [Music.UID]'s.
+        when (val item = _currentItem.value) {
-     * @param uids The [Music.UID]s of the [Artist]s to [currentArtists] to.
+            is Song -> {
-     */
+                _artistChoices.value = item.artists
-    fun setArtistUids(uids: Array<Music.UID>) {
+                _genreChoices.value = item.genres
-        val library = unlikelyToBeNull(musicStore.library)
+            }
-        // Map the UIDs to artist instances and filter out the ones that can't be found.
+            is Album -> _artistChoices.value = item.artists
-        _currentArtists.value = uids.mapNotNull { library.find<Artist>(it) }.ifEmpty { null }
+            else -> {}
+        }
     }
+
 }

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

@@ -210,7 +210,7 @@ class PlaybackPanelFragment :
     /** Navigate to one of the currently playing [Song]'s Artists. */
     private fun navigateToCurrentArtist() {
         val song = playbackModel.song.value ?: return
-        navModel.exploreNavigateTo(song.artists)
+        navModel.exploreNavigateToParentArtist(song)
     }
 
     /** Navigate to the currently playing [Song]'s albums. */

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

@@ -70,13 +70,21 @@ class PlaybackViewModel(application: Application) :
 
     private val _artistPlaybackPickerSong = MutableStateFlow<Song?>(null)
     /**
-     * Flag signaling to open a picker dialog in order to resolve an ambiguous [Artist] choice when
+     * Flag signaling to open a picker dialog in order to resolve an ambiguous choice when
      * playing a [Song] from one of it's [Artist]s.
      * @see playFromArtist
      */
-    val artistPlaybackPickerSong: StateFlow<Song?>
+    val artistPickerSong: StateFlow<Song?>
         get() = _artistPlaybackPickerSong
 
+    private val _genrePlaybackPickerSong = MutableStateFlow<Song?>(null)
+    /**
+     * Flag signaling to open a picker dialog in order to resolve an ambiguous choice when playing
+     * a [Song] from one of it's [Genre]s.
+     */
+    val genrePickerSong: StateFlow<Song?>
+        get() = _genrePlaybackPickerSong
+
     /**
      * The current audio session ID of the internal player. Null if no [InternalPlayer] is
      * available.
@@ -178,11 +186,18 @@ class PlaybackViewModel(application: Application) :
     /**
      * PLay a [Song] from one of it's [Genre]s.
      * @param song The [Song] to play.
-     * @param genre The [Genre] to play from. Must be linked to the [Song].
+     * @param genre The [Genre] to play from. Must be linked to the [Song]. If null, the user will
+     * be prompted on what artist to play. Defaults to null.
      */
-    fun playFromGenre(song: Song, genre: Genre) {
+    fun playFromGenre(song: Song, genre: Genre? = null) {
-        check(genre.songs.contains(song)) { "Invalid input: Genre is not linked to song" }
+        if (genre != null) {
-        playbackManager.play(song, genre, settings)
+            check(genre.songs.contains(song)) { "Invalid input: Genre is not linked to song" }
+            playbackManager.play(song, genre, settings)
+        } else if (song.genres.size == 1) {
+            playbackManager.play(song, song.genres[0], settings)
+        } else {
+            _genrePlaybackPickerSong.value = song
+        }
     }
 
     /**

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

@@ -137,11 +137,11 @@ class SearchFragment : ListFragment<FragmentSearchBinding>() {
     override fun onRealClick(music: Music) {
         when (music) {
             is Song ->
-                when (val mode = Settings(requireContext()).libPlaybackMode) {
+                when (Settings(requireContext()).libPlaybackMode) {
                     MusicMode.SONGS -> playbackModel.playFromAll(music)
                     MusicMode.ALBUMS -> playbackModel.playFromAlbum(music)
                     MusicMode.ARTISTS -> playbackModel.playFromArtist(music)
-                    else -> error("Unexpected playback mode: $mode")
+                    MusicMode.GENRES -> playbackModel.playFromGenre(music)
                 }
             is MusicParent -> navModel.exploreNavigateTo(music)
         }

app/src/main/java/org/oxycblt/auxio/settings/Settings.kt

@@ -113,10 +113,11 @@ class Settings(private val context: Context, private val callback: Callback? = n
 
         fun Int.migratePlaybackMode() =
             when (this) {
-                // Genre playback mode was removed in 3.0.0
+                // Convert PlaybackMode into MusicMode
                 IntegerTable.PLAYBACK_MODE_ALL_SONGS -> MusicMode.SONGS
                 IntegerTable.PLAYBACK_MODE_IN_ARTIST -> MusicMode.ARTISTS
                 IntegerTable.PLAYBACK_MODE_IN_ALBUM -> MusicMode.ALBUMS
+                IntegerTable.PLAYBACK_MODE_IN_GENRE -> MusicMode.GENRES
                 else -> null
             }
 

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

@@ -21,8 +21,10 @@ import androidx.lifecycle.ViewModel
 import androidx.navigation.NavDirections
 import kotlinx.coroutines.flow.MutableStateFlow
 import kotlinx.coroutines.flow.StateFlow
+import org.oxycblt.auxio.music.Album
 import org.oxycblt.auxio.music.Artist
 import org.oxycblt.auxio.music.Music
+import org.oxycblt.auxio.music.Song
 import org.oxycblt.auxio.util.logD
 
 /** A [ViewModel] that handles complicated navigation functionality. */
@@ -42,14 +44,14 @@ class NavigationViewModel : ViewModel() {
     val exploreNavigationItem: StateFlow<Music?>
         get() = _exploreNavigationItem
 
-    private val _exploreNavigationArtists = MutableStateFlow<List<Artist>?>(null)
+    private val _exploreArtistNavigationItem = MutableStateFlow<Music?>(null)
     /**
-     * Variation of [exploreNavigationItem] for situations where the choice of [Artist] to navigate
+     * Variation of [exploreNavigationItem] for situations where the choice of parent [Artist] to
-     * to is ambiguous. Only intended for use by MainFragment, as the resolved choice will
+     * navigate to is ambiguous. Only intended for use by MainFragment, as the resolved choice will
      * eventually be assigned to [exploreNavigationItem].
      */
-    val exploreNavigationArtists: StateFlow<List<Artist>?>
+    val exploreArtistNavigationItem: StateFlow<Music?>
-        get() = _exploreNavigationArtists
+        get() = _exploreArtistNavigationItem
 
     /**
      * Navigate to something in the main navigation graph. This can be used by UIs in the explore
@@ -89,12 +91,25 @@ class NavigationViewModel : ViewModel() {
     }
 
     /**
-     * Navigate to an [Artist] out of a list of [Artist]s, like [exploreNavigateTo].
+     * Navigate to one of the parent [Artist]'s of the given [Song].
-     * @param artists The [Artist]s to navigate to. In the case of multiple artists, the user will
+     * @param song The [Song] to navigate with. If there are multiple parent [Artist]s,
-     * be prompted with a choice on which [Artist] to navigate to.
+     * a picker dialog will be shown.
      */
-    fun exploreNavigateTo(artists: List<Artist>) {
+    fun exploreNavigateToParentArtist(song: Song) {
-        if (_exploreNavigationArtists.value != null) {
+        exploreNavigateToParentArtistImpl(song, song.artists)
+    }
+
+    /**
+     * Navigate to one of the parent [Artist]'s of the given [Album].
+     * @param album The [Album] to navigate with. If there are multiple parent [Artist]s,
+     * a picker dialog will be shown.
+     */
+    fun exploreNavigateToParentArtist(album: Album) {
+        exploreNavigateToParentArtistImpl(album, album.artists)
+    }
+
+    private fun exploreNavigateToParentArtistImpl(item: Music, artists: List<Artist>) {
+        if (_exploreArtistNavigationItem.value != null) {
             logD("Already navigating, not doing explore action")
             return
         }
@@ -103,7 +118,7 @@ class NavigationViewModel : ViewModel() {
             exploreNavigateTo(artists[0])
         } else {
             logD("Navigating to a choice of ${artists.map { it.rawName }}")
-            _exploreNavigationArtists.value = artists
+            _exploreArtistNavigationItem.value = item
         }
     }
 
@@ -114,7 +129,7 @@ class NavigationViewModel : ViewModel() {
     fun finishExploreNavigation() {
         logD("Finishing explore navigation process")
         _exploreNavigationItem.value = null
-        _exploreNavigationArtists.value = null
+        _exploreArtistNavigationItem.value = null
     }
 }
 

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

@@ -23,6 +23,9 @@
         <action
             android:id="@+id/action_pick_navigation_artist"
             app:destination="@id/artist_navigation_picker_dialog" />
+        <action
+            android:id="@+id/action_pick_playback_genre"
+            app:destination="@id/genre_playback_picker_dialog" />
     </fragment>
 
     <dialog
@@ -31,7 +34,7 @@
         android:label="artist_playback_picker_dialog"
         tools:layout="@layout/dialog_music_picker">
         <argument
-            android:name="songUid"
+            android:name="itemUid"
             app:argType="org.oxycblt.auxio.music.Music$UID" />
     </dialog>
 
@@ -41,8 +44,18 @@
         android:label="artist_navigation_picker_dialog"
         tools:layout="@layout/dialog_music_picker">
         <argument
-            android:name="artistUids"
+            android:name="itemUid"
-            app:argType="org.oxycblt.auxio.music.Music$UID[]" />
+            app:argType="org.oxycblt.auxio.music.Music$UID" />
+    </dialog>
+
+    <dialog
+        android:id="@+id/genre_playback_picker_dialog"
+        android:name="org.oxycblt.auxio.music.picker.GenrePlaybackPickerDialog"
+        android:label="genre_playback_picker_dialog"
+        tools:layout="@layout/dialog_music_picker">
+        <argument
+            android:name="itemUid"
+            app:argType="org.oxycblt.auxio.music.Music$UID" />
     </dialog>
 
     <dialog
@@ -51,7 +64,7 @@
         android:label="song_detail_dialog"
         tools:layout="@layout/dialog_song_detail">
         <argument
-            android:name="songUid"
+            android:name="itemUid"
             app:argType="org.oxycblt.auxio.music.Music$UID" />
     </dialog>
 

app/src/main/res/values-ar-rIQ/strings.xml

@@ -23,7 +23,7 @@
     <string name="lbl_playback">يعمل الآن</string>
     <string name="lbl_play">تشغيل</string>
     <string name="lbl_shuffle">خلط</string>
-    <string name="set_playback_mode_all">تشغيل من جميع الاغاني</string>
+    <string name="set_playback_mode_songs">تشغيل من جميع الاغاني</string>
     <string name="set_playback_mode_album">تشغيل من البوم</string>
     <string name="set_playback_mode_artist">تشغيل من فنان</string>
     <string name="lbl_queue">طابور</string>

app/src/main/res/values-cs/strings.xml

@@ -29,7 +29,7 @@
     <string name="lbl_playback">Právě hraje</string>
     <string name="lbl_play">Přehrát</string>
     <string name="lbl_shuffle">Náhodně</string>
-    <string name="set_playback_mode_all">Přehrát ze všech skladeb</string>
+    <string name="set_playback_mode_songs">Přehrát ze všech skladeb</string>
     <string name="set_playback_mode_album">Přehrát z alba</string>
     <string name="set_playback_mode_artist">Přehrát od umělce</string>
     <string name="lbl_queue">Fronta</string>

app/src/main/res/values-de/strings.xml

@@ -15,7 +15,7 @@
     <string name="lbl_sort_asc">Aufsteigend</string>
     <string name="lbl_play">Abspielen</string>
     <string name="lbl_shuffle">Zufällig</string>
-    <string name="set_playback_mode_all">Von allen Lieder abspielen</string>
+    <string name="set_playback_mode_songs">Von allen Lieder abspielen</string>
     <string name="set_playback_mode_album">Von Album abspielen</string>
     <string name="lbl_playback">Aktuelle Wiedergabe</string>
     <string name="lbl_queue">Warteschlange</string>

app/src/main/res/values-es/strings.xml

@@ -23,7 +23,7 @@
     <string name="lbl_playback">En reproducción</string>
     <string name="lbl_play">Reproducir</string>
     <string name="lbl_shuffle">Mezcla</string>
-    <string name="set_playback_mode_all">Reproducir todo</string>
+    <string name="set_playback_mode_songs">Reproducir todo</string>
     <string name="set_playback_mode_album">Reproducir por álbum</string>
     <string name="set_playback_mode_artist">Reproducir por artista</string>
     <string name="lbl_queue">Cola</string>

app/src/main/res/values-hr/strings.xml

@@ -85,7 +85,7 @@
     <string name="set_pre_amp_warning">Upozorenje: Postavljanje pretpojačala na visoke razine može uzrokovati vrhunce tonova u nekim zvučnim zapisima.</string>
     <string name="set_library_song_playback_mode">Kada se reproducira iz zbirke</string>
     <string name="set_detail_song_playback_mode">Kada se reproducira iz detalja o predmetu</string>
-    <string name="set_playback_mode_all">Reproduciraj od svih pjesama</string>
+    <string name="set_playback_mode_songs">Reproduciraj od svih pjesama</string>
     <string name="set_reindex">Aktualiziraj glazbu</string>
     <string name="set_reindex_desc">Ponovo učitaj glazbenu biblioteku, koristeći predmemorirane oznake kada je to moguće</string>
     <string name="set_dirs">Mape glazbe</string>

app/src/main/res/values-in/strings.xml

@@ -95,7 +95,7 @@
     <string name="set_pre_amp_with">Penyesuaian dengan tag</string>
     <string name="set_pre_amp_warning">Peringatan: Mengubah pre-amp ke nilai positif yang tinggi dapat mengakibatkan puncak pada beberapa trek audio.</string>
     <string name="set_playback_mode_none">Putar dari item yang ditampilkan</string>
-    <string name="set_playback_mode_all">Putar dari semua lagu</string>
+    <string name="set_playback_mode_songs">Putar dari semua lagu</string>
     <string name="set_keep_shuffle_desc">Tetap mengacak saat memutar lagu baru</string>
     <string name="set_repeat_pause">Jeda pada pengulangan</string>
     <string name="set_rewind_prev">Putar balik sebelum melompat ke belakang</string>

app/src/main/res/values-it/strings.xml

@@ -23,7 +23,7 @@
     <string name="lbl_playback">Ora in riproduzione</string>
     <string name="lbl_play">Riproduci</string>
     <string name="lbl_shuffle">Mescola</string>
-    <string name="set_playback_mode_all">Riproduci da tutte le canzoni</string>
+    <string name="set_playback_mode_songs">Riproduci da tutte le canzoni</string>
     <string name="set_playback_mode_album">Riproduci dal disco</string>
     <string name="set_playback_mode_artist">Riproduci dall\'artista</string>
     <string name="lbl_queue">Coda</string>

app/src/main/res/values-ko/strings.xml

@@ -27,7 +27,7 @@
     <string name="lbl_playback">지금 재생 중</string>
     <string name="lbl_play">재생</string>
     <string name="lbl_shuffle">셔플</string>
-    <string name="set_playback_mode_all">모든 곡에서 재생</string>
+    <string name="set_playback_mode_songs">모든 곡에서 재생</string>
     <string name="set_playback_mode_album">앨범에서 재생</string>
     <string name="set_playback_mode_artist">아티스트에서 재생</string>
     <string name="lbl_queue">대기열</string>

app/src/main/res/values-lt/strings.xml

@@ -176,7 +176,7 @@
     <string name="set_dirs_mode_exclude_desc">Muzika <b>nebus</b> įkeliama iš pridėtų aplankų jūs pridėsite.</string>
     <string name="set_dirs_mode_include">Įtraukti</string>
     <string name="desc_clear_queue_item">Pašalinti šią eilės dainą</string>
-    <string name="set_playback_mode_all">Groti iš visų dainų</string>
+    <string name="set_playback_mode_songs">Groti iš visų dainų</string>
     <string name="set_playback_mode_none">Groti iš parodyto elemento</string>
     <string name="set_playback_mode_album">Groti iš albumo</string>
     <string name="set_playback_mode_artist">Groti iš atlikėjo</string>

app/src/main/res/values-nl/strings.xml

@@ -17,7 +17,7 @@
     <string name="lbl_sort_asc">Oplopend</string>
     <string name="lbl_play">Afspelen</string>
     <string name="lbl_shuffle">Shuffle</string>
-    <string name="set_playback_mode_all">Speel van alle nummers </string>
+    <string name="set_playback_mode_songs">Speel van alle nummers </string>
     <string name="set_playback_mode_album">Speel af van album </string>
     <string name="set_playback_mode_artist">Speel van artiest </string>
     <string name="lbl_playback">Afspeelscherm</string>

app/src/main/res/values-pl/strings.xml

@@ -136,7 +136,7 @@
     <string name="lbl_equalizer">Equalizer</string>
     <string name="lbl_size">Rozmiar</string>
     <string name="err_no_dirs">Brak folderów</string>
-    <string name="set_playback_mode_all">Odtwórz wszystkie utwory</string>
+    <string name="set_playback_mode_songs">Odtwórz wszystkie utwory</string>
     <string name="set_playback_mode_album">Odtwórz album</string>
     <string name="set_headset_autoplay_desc">Zacznij odtawrzanie po podłączeniu słuchawek (może nie działać na wszystkich urządzeniach)</string>
     <string name="set_reindex">Załaduj ponownie bibliotekę</string>

app/src/main/res/values-pt-rBR/strings.xml

@@ -166,7 +166,7 @@
     <string name="set_round_mode_desc">Ativar cantos arredondados em elementos adicionais da interface do usuário (requer que as capas dos álbuns sejam arredondadas)</string>
     <string name="set_replay_gain">Modo de normalização de volume (ReplayGain)</string>
     <string name="set_playback_mode_none">Reproduzir a partir do item mostrado</string>
-    <string name="set_playback_mode_all">Reproduzir de todas as músicas</string>
+    <string name="set_playback_mode_songs">Reproduzir de todas as músicas</string>
     <string name="set_replay_gain_album">Preferir álbum</string>
     <string name="set_replay_gain_dynamic">Prefira o álbum se estiver tocando</string>
     <string name="set_observing">Recarregamento automático</string>

app/src/main/res/values-pt-rPT/strings.xml

@@ -189,7 +189,7 @@
     <string name="set_replay_gain">Estratégia do ganho de repetição</string>
     <string name="set_replay_gain_album">Preferir álbum</string>
     <string name="set_pre_amp_desc">O pré-amplificador é aplicado ao ajuste existente durante a reprodução</string>
-    <string name="set_playback_mode_all">Reproduzir de todas as músicas</string>
+    <string name="set_playback_mode_songs">Reproduzir de todas as músicas</string>
     <string name="set_repeat_pause_desc">Pausa quando uma música se repete</string>
     <string name="set_wipe_desc">Limpe o estado de reprodução salvo anteriormente (se houver)</string>
     <string name="set_restore_state">Restaurar o estado de reprodução</string>

app/src/main/res/values-ru/strings.xml

@@ -23,7 +23,7 @@
     <string name="lbl_playback">Сейчас играет</string>
     <string name="lbl_play">Играть</string>
     <string name="lbl_shuffle">Перемешать</string>
-    <string name="set_playback_mode_all">Играть все треки</string>
+    <string name="set_playback_mode_songs">Играть все треки</string>
     <string name="set_playback_mode_album">Играть альбом</string>
     <string name="set_playback_mode_artist">Играть исполнителя</string>
     <string name="lbl_queue">Очередь</string>

app/src/main/res/values-tr/strings.xml

@@ -94,7 +94,7 @@
     <string name="set_pre_amp_with">Etiket ile ayarla</string>
     <string name="set_pre_amp_warning">Uyarı: Ön amfinin yüksek bir pozitif değere değiştirilmesi bazı ses parçalarında pik yapmaya neden olabilir.</string>
     <string name="set_playback_mode_none">Gösterilen öğeden çal</string>
-    <string name="set_playback_mode_all">Tüm şarkılardan çal</string>
+    <string name="set_playback_mode_songs">Tüm şarkılardan çal</string>
     <string name="set_playback_mode_album">Albümden çal</string>
     <string name="set_dirs">Müzik klasörleri</string>
     <string name="set_dirs_mode_include_desc">Müzik <b>yalnızca</b> eklediğiniz klasörlerden yüklenecektir.</string>

app/src/main/res/values-zh-rCN/strings.xml

@@ -23,7 +23,7 @@
     <string name="lbl_playback">正在播放</string>
     <string name="lbl_play">播放</string>
     <string name="lbl_shuffle">随机</string>
-    <string name="set_playback_mode_all">从全部歌曲开始播放</string>
+    <string name="set_playback_mode_songs">从全部歌曲开始播放</string>
     <string name="set_playback_mode_album">从专辑开始播放</string>
     <string name="set_playback_mode_artist">从艺术家播放</string>
     <string name="lbl_queue">播放队列</string>

app/src/main/res/values/settings.xml

@@ -99,22 +99,25 @@
     </integer-array>
 
     <string-array name="entries_library_song_playback_mode">
-        <item>@string/set_playback_mode_all</item>
+        <item>@string/set_playback_mode_songs</item>
         <item>@string/set_playback_mode_artist</item>
         <item>@string/set_playback_mode_album</item>
+        <item>@string/set_playback_mode_genre</item>
     </string-array>
 
     <integer-array name="values_library_song_playback_mode">
         <item>@integer/music_mode_songs</item>
         <item>@integer/music_mode_artist</item>
         <item>@integer/music_mode_album</item>
+        <item>@integer/music_mode_genre</item>
     </integer-array>
 
     <string-array name="entries_detail_song_playback_mode">
         <item>@string/set_playback_mode_none</item>
-        <item>@string/set_playback_mode_all</item>
+        <item>@string/set_playback_mode_songs</item>
         <item>@string/set_playback_mode_artist</item>
         <item>@string/set_playback_mode_album</item>
+        <item>@string/set_playback_mode_genre</item>
     </string-array>
 
     <integer-array name="values_detail_song_playback_mode">
@@ -122,6 +125,7 @@
         <item>@integer/music_mode_songs</item>
         <item>@integer/music_mode_artist</item>
         <item>@integer/music_mode_album</item>
+        <item>@integer/music_mode_genre</item>
     </integer-array>
 
     <string-array name="entries_replay_gain">
@@ -141,6 +145,7 @@
     <integer name="theme_dark">2</integer>
 
     <integer name="music_mode_none">-2147483648</integer>
+    <integer name="music_mode_genre">0xA108</integer>
     <integer name="music_mode_artist">0xA109</integer>
     <integer name="music_mode_album">0xA10A</integer>
     <integer name="music_mode_songs">0xA10B</integer>

app/src/main/res/values/strings.xml

@@ -202,9 +202,10 @@
     <string name="set_library_song_playback_mode">When playing from the library</string>
     <string name="set_detail_song_playback_mode">When playing from item details</string>
     <string name="set_playback_mode_none">Play from shown item</string>
-    <string name="set_playback_mode_all">Play from all songs</string>
+    <string name="set_playback_mode_songs">Play from all songs</string>
     <string name="set_playback_mode_album">Play from album</string>
     <string name="set_playback_mode_artist">Play from artist</string>
+    <string name="set_playback_mode_genre">Play from genre</string>
     <string name="set_keep_shuffle">Remember shuffle</string>
     <string name="set_keep_shuffle_desc">Keep shuffle on when playing a new song</string>
     <string name="set_rewind_prev">Rewind before skipping back</string>