Update stored DetailViewModel items

Change the stored items in DetailViewModel to LiveData. Remove the need to reset the stored items when a fragment is destroyed.

AuxioTODO

@@ -24,19 +24,12 @@ TODO:
 
 /library/
 
-- Add genres
 - ? Move into ViewPager ?
 - Sorting
 - Search
     - ? Show Artists, Albums, and Songs in search ?
 - Exit functionality
 
-/other/
-
-- ? Condense detail fragments into a single fragment ?
-- Condense artist/album recyclerview items into single item
-- Remove binding adapters
-
 To be added:
 /prefs/
 /playback/

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

@@ -33,12 +33,14 @@ class AlbumDetailFragment : Fragment() {
 
         // If DetailViewModel isn't already storing the album, get it from MusicViewModel
         // using the ID given by the navigation arguments.
-        if (detailModel.currentAlbum == null) {
+        if (detailModel.currentAlbum.value!!.id != args.albumId) {
             val musicModel: MusicViewModel by activityViewModels()
 
-            detailModel.currentAlbum = musicModel.albums.value!!.find {
+            detailModel.updateAlbum(
+                musicModel.albums.value!!.find {
                     it.id == args.albumId
                 }!!
+            )
         }
 
         val songAdapter = DetailSongAdapter(
@@ -49,7 +51,7 @@ class AlbumDetailFragment : Fragment() {
 
         binding.lifecycleOwner = this
         binding.detailModel = detailModel
-        binding.album = detailModel.currentAlbum
+        binding.album = detailModel.currentAlbum.value!!
 
         binding.albumSongRecycler.apply {
             adapter = songAdapter
@@ -61,20 +63,16 @@ class AlbumDetailFragment : Fragment() {
             findNavController().navigateUp()
         }
 
-        // If the album was shown directly from LibraryFragment [No parent artist stored],
+        // If the album was shown directly from LibraryFragment [No parent artist stored]
-        // then enable the ability to navigate upwards to the album's parent artist.
+        // Then enable the ability to navigate upwards to the parent artist
-        if (detailModel.currentArtist == null) {
+        if (detailModel.currentArtist.value!!.id != detailModel.currentAlbum.value!!.artist.id) {
-            detailModel.doneWithNavToParent()
+            detailModel.currentArtist.observe(viewLifecycleOwner) {
-
+                if (it.id == detailModel.currentAlbum.value!!.artist.id) {
-            detailModel.navToParentArtist.observe(viewLifecycleOwner) {
-                if (it) {
                     findNavController().navigate(
                         AlbumDetailFragmentDirections.actionShowParentArtist(
-                            detailModel.currentAlbum!!.artist.id
+                            detailModel.currentAlbum.value!!.artist.id
                         )
                     )
-
-                    detailModel.doneWithNavToParent()
                 }
             }
 
@@ -87,7 +85,7 @@ class AlbumDetailFragment : Fragment() {
 
             // Then update the sort mode of the album adapter.
             songAdapter.submitList(
-                detailModel.currentAlbum!!.songs.sortedWith(
+                detailModel.currentAlbum.value!!.songs.sortedWith(
                     SortMode.songSortComparators.getOrDefault(
                         mode,
 
@@ -99,7 +97,7 @@ class AlbumDetailFragment : Fragment() {
         }
 
         // Don't enable the sort button if there's only one song [or less]
-        if (detailModel.currentAlbum!!.numSongs < 2) {
+        if (detailModel.currentAlbum.value!!.numSongs < 2) {
             binding.albumSortButton.imageTintList = ColorStateList.valueOf(
                 R.color.inactive_color.toColor(requireContext())
             )
@@ -111,10 +109,4 @@ class AlbumDetailFragment : Fragment() {
 
         return binding.root
     }
-
-    override fun onDestroy() {
-        super.onDestroy()
-
-        detailModel.currentAlbum = null
-    }
 }

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

@@ -34,11 +34,14 @@ class ArtistDetailFragment : Fragment() {
 
         // If DetailViewModel isn't already storing the artist, get it from MusicViewModel
         // using the ID given by the navigation arguments
-        if (detailModel.currentArtist == null) {
+        if (detailModel.currentArtist.value!!.id != args.artistId) {
             val musicModel: MusicViewModel by activityViewModels()
-            detailModel.currentArtist = musicModel.artists.value!!.find {
+
+            detailModel.updateArtist(
+                musicModel.artists.value!!.find {
                     it.id == args.artistId
                 }!!
+            )
         }
 
         val albumAdapter = DetailAlbumAdapter(
@@ -49,7 +52,7 @@ class ArtistDetailFragment : Fragment() {
 
         binding.lifecycleOwner = this
         binding.detailModel = detailModel
-        binding.artist = detailModel.currentArtist!!
+        binding.artist = detailModel.currentArtist.value!!
 
         binding.artistAlbumRecycler.apply {
             adapter = albumAdapter
@@ -67,7 +70,7 @@ class ArtistDetailFragment : Fragment() {
 
             // Then update the sort mode of the album adapter.
             albumAdapter.submitList(
-                detailModel.currentArtist!!.albums.sortedWith(
+                detailModel.currentArtist.value!!.albums.sortedWith(
                     SortMode.albumSortComparators.getOrDefault(
                         mode,
 
@@ -79,7 +82,7 @@ class ArtistDetailFragment : Fragment() {
         }
 
         // Don't enable the sort button if there is only one album [Or less]
-        if (detailModel.currentArtist!!.numAlbums < 2) {
+        if (detailModel.currentArtist.value!!.numAlbums < 2) {
             binding.artistSortButton.imageTintList = ColorStateList.valueOf(
                 R.color.inactive_color.toColor(requireContext())
             )
@@ -98,14 +101,6 @@ class ArtistDetailFragment : Fragment() {
         detailModel.isAlreadyNavigating = false
     }
 
-    override fun onDestroy() {
-        super.onDestroy()
-
-        // Reset the stored artist so that the next instance of ArtistDetailFragment
-        // will not read it.
-        detailModel.currentArtist = null
-    }
-
     private fun navToAlbum(album: Album) {
         // Don't navigate if an item already has been selected.
         if (!detailModel.isAlreadyNavigating) {

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

@@ -11,9 +11,6 @@ import org.oxycblt.auxio.recycler.SortMode
 class DetailViewModel : ViewModel() {
     var isAlreadyNavigating = false
 
-    private val mNavToParentArtist = MutableLiveData<Boolean>()
-    val navToParentArtist: LiveData<Boolean> get() = mNavToParentArtist
-
     private val mGenreSortMode = MutableLiveData(SortMode.ALPHA_DOWN)
     val genreSortMode: LiveData<SortMode> get() = mGenreSortMode
 
@@ -23,16 +20,28 @@ class DetailViewModel : ViewModel() {
     private val mAlbumSortMode = MutableLiveData(SortMode.NUMERIC_DOWN)
     val albumSortMode: LiveData<SortMode> get() = mAlbumSortMode
 
-    var currentGenre: Genre? = null
+    // Current music models being shown
-    var currentArtist: Artist? = null
+    // These have placeholder values in them so that they don't
-    var currentAlbum: Album? = null
+    // have to be checked if they're null.
+    private val mCurrentGenre = MutableLiveData(Genre(name = ""))
+    val currentGenre: LiveData<Genre> get() = mCurrentGenre
 
-    fun navToParent() {
+    private val mCurrentArtist = MutableLiveData(Artist(name = ""))
-        mNavToParentArtist.value = true
+    val currentArtist: LiveData<Artist> get() = mCurrentArtist
+
+    private val mCurrentAlbum = MutableLiveData(Album(name = "", artistName = ""))
+    val currentAlbum: LiveData<Album> get() = mCurrentAlbum
+
+    fun updateGenre(genre: Genre) {
+        mCurrentGenre.value = genre
     }
 
-    fun doneWithNavToParent() {
+    fun updateArtist(artist: Artist) {
-        mNavToParentArtist.value = false
+        mCurrentArtist.value = artist
+    }
+
+    fun updateAlbum(album: Album) {
+        mCurrentAlbum.value = album
     }
 
     fun incrementGenreSortMode() {

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

@@ -34,11 +34,14 @@ class GenreDetailFragment : Fragment() {
 
         // If DetailViewModel isn't already storing the genre, get it from MusicViewModel
         // using the ID given by the navigation arguments
-        if (detailModel.currentGenre == null) {
+        if (detailModel.currentGenre.value!!.id != args.genreId) {
             val musicModel: MusicViewModel by activityViewModels()
-            detailModel.currentGenre = musicModel.genres.value!!.find {
+
+            detailModel.updateGenre(
+                musicModel.genres.value!!.find {
                     it.id == args.genreId
                 }!!
+            )
         }
 
         val albumAdapter = DetailArtistAdapter(
@@ -49,7 +52,7 @@ class GenreDetailFragment : Fragment() {
 
         binding.lifecycleOwner = this
         binding.detailModel = detailModel
-        binding.genre = detailModel.currentGenre!!
+        binding.genre = detailModel.currentGenre.value
 
         binding.genreArtistRecycler.adapter = albumAdapter
         binding.genreArtistRecycler.applyDivider()
@@ -63,9 +66,9 @@ class GenreDetailFragment : Fragment() {
             // Update the current sort icon
             binding.genreSortButton.setImageResource(mode.iconRes)
 
-            // Then update the sort mode of the album adapter.
+            // Then update the sort mode of the artist adapter.
             albumAdapter.submitList(
-                detailModel.currentGenre!!.artists.sortedWith(
+                detailModel.currentGenre.value!!.artists.sortedWith(
                     SortMode.artistSortComparators.getOrDefault(
                         mode,
 
@@ -77,7 +80,7 @@ class GenreDetailFragment : Fragment() {
         }
 
         // Don't enable the sort button if there is only one artist [Or less]
-        if (detailModel.currentGenre!!.numArtists < 2) {
+        if (detailModel.currentGenre.value!!.numArtists < 2) {
             binding.genreSortButton.imageTintList = ColorStateList.valueOf(
                 R.color.inactive_color.toColor(requireContext())
             )
@@ -96,14 +99,6 @@ class GenreDetailFragment : Fragment() {
         detailModel.isAlreadyNavigating = false
     }
 
-    override fun onDestroy() {
-        super.onDestroy()
-
-        // Reset the stored artist so that the next instance of GenreDetailFragment
-        // will not read it.
-        detailModel.currentGenre = null
-    }
-
     private fun navToArtist(artist: Artist) {
         // Don't navigate if an item already has been selected.
         if (!detailModel.isAlreadyNavigating) {

app/src/main/java/org/oxycblt/auxio/detail/adapters/DetailAlbumAdapter.kt

@@ -3,9 +3,7 @@ package org.oxycblt.auxio.detail.adapters
 import android.view.LayoutInflater
 import android.view.ViewGroup
 import androidx.recyclerview.widget.ListAdapter
-import org.oxycblt.auxio.databinding.ItemAlbumBinding
 import org.oxycblt.auxio.databinding.ItemArtistAlbumBinding
-import org.oxycblt.auxio.databinding.ItemArtistBinding
 import org.oxycblt.auxio.music.Album
 import org.oxycblt.auxio.recycler.BaseViewHolder
 import org.oxycblt.auxio.recycler.ClickListener

app/src/main/java/org/oxycblt/auxio/detail/adapters/DetailArtistAdapter.kt

@@ -3,10 +3,8 @@ package org.oxycblt.auxio.detail.adapters
 import android.view.LayoutInflater
 import android.view.ViewGroup
 import androidx.recyclerview.widget.ListAdapter
-import org.oxycblt.auxio.databinding.ItemArtistBinding
 import org.oxycblt.auxio.databinding.ItemGenreArtistBinding
 import org.oxycblt.auxio.music.Artist
-import org.oxycblt.auxio.music.bindArtistCounts
 import org.oxycblt.auxio.recycler.BaseViewHolder
 import org.oxycblt.auxio.recycler.ClickListener
 import org.oxycblt.auxio.recycler.DiffCallback

app/src/main/java/org/oxycblt/auxio/library/adapters/AlbumAdapter.kt

@@ -5,7 +5,6 @@ import android.view.ViewGroup
 import androidx.recyclerview.widget.RecyclerView
 import org.oxycblt.auxio.databinding.ItemAlbumBinding
 import org.oxycblt.auxio.music.Album
-import org.oxycblt.auxio.music.bindAlbumSongs
 import org.oxycblt.auxio.recycler.BaseViewHolder
 import org.oxycblt.auxio.recycler.ClickListener
 

app/src/main/java/org/oxycblt/auxio/library/adapters/ArtistAdapter.kt

@@ -5,7 +5,6 @@ import android.view.ViewGroup
 import androidx.recyclerview.widget.RecyclerView
 import org.oxycblt.auxio.databinding.ItemArtistBinding
 import org.oxycblt.auxio.music.Artist
-import org.oxycblt.auxio.music.bindArtistCounts
 import org.oxycblt.auxio.recycler.BaseViewHolder
 import org.oxycblt.auxio.recycler.ClickListener
 

app/src/main/java/org/oxycblt/auxio/music/Models.kt

@@ -25,7 +25,7 @@ data class Song(
 
 // Album
 data class Album(
-    override val id: Long = -1,
+    override val id: Long = Long.MIN_VALUE,
     override val name: String,
     val artistName: String,
     val coverUri: Uri = Uri.EMPTY,
@@ -47,7 +47,7 @@ data class Album(
 
 // Artist
 data class Artist(
-    override val id: Long = -1,
+    override val id: Long = Long.MIN_VALUE,
     override var name: String,
     val givenGenres: MutableList<Genre> = mutableListOf()
 ) : BaseModel() {
@@ -67,7 +67,7 @@ data class Artist(
 
 // Genre
 data class Genre(
-    override val id: Long = -1,
+    override val id: Long = Long.MIN_VALUE,
     override var name: String,
 ) : BaseModel() {
     val artists = mutableListOf<Artist>()

app/src/main/java/org/oxycblt/auxio/music/MusicUtils.kt

@@ -1,7 +1,6 @@
 package org.oxycblt.auxio.music
 
 import android.content.ContentUris
-import android.content.Context
 import android.net.Uri
 import android.provider.MediaStore
 import android.text.format.DateUtils
@@ -98,7 +97,11 @@ fun TextView.bindGenreCounts(genre: Genre) {
 // TODO: Add option to list all genres
 @BindingAdapter("artistGenre")
 fun TextView.bindArtistGenre(artist: Artist) {
-    text = artist.genres[0].name
+    text = if (artist.genres.isNotEmpty()) {
+        artist.genres[0].name
+    } else {
+        context.getString(R.string.placeholder_genre)
+    }
 }
 
 // Get the artist counts

app/src/main/java/org/oxycblt/auxio/songs/SongAdapter.kt

@@ -31,6 +31,7 @@ class SongAdapter(
 
         override fun onBind(model: Song) {
             binding.song = model
+
             binding.songName.requestLayout()
             binding.songInfo.requestLayout()
         }

app/src/main/res/layout/fragment_album_detail.xml

@@ -77,7 +77,7 @@
                     android:layout_marginStart="@dimen/margin_medium"
                     android:clickable="true"
                     android:focusable="true"
-                    android:onClick="@{() -> detailModel.navToParent()}"
+                    android:onClick="@{() -> detailModel.updateArtist(album.artist)}"
                     android:text="@{album.artist.name}"
                     android:textAppearance="?android:attr/textAppearanceListItem"
                     android:textColor="?android:attr/textColorSecondary"