recycler: add selection adapter framework

Add a framework for selection-based adapters.

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

@@ -30,7 +30,7 @@ import org.oxycblt.auxio.detail.DiscHeader
 import org.oxycblt.auxio.music.Album
 import org.oxycblt.auxio.music.Song
 import org.oxycblt.auxio.playback.formatDurationMs
-import org.oxycblt.auxio.ui.recycler.IndicatorAdapter
+import org.oxycblt.auxio.ui.recycler.PlayingIndicatorAdapter
 import org.oxycblt.auxio.ui.recycler.Item
 import org.oxycblt.auxio.ui.recycler.MenuItemListener
 import org.oxycblt.auxio.ui.recycler.SimpleItemCallback
@@ -173,7 +173,7 @@ class DiscHeaderViewHolder(private val binding: ItemDiscHeaderBinding) :
 }
 
 private class AlbumSongViewHolder private constructor(private val binding: ItemAlbumSongBinding) :
-    IndicatorAdapter.ViewHolder(binding.root) {
+    PlayingIndicatorAdapter.ViewHolder(binding.root) {
     fun bind(item: Song, listener: MenuItemListener) {
         // Hide the track number view if the song does not have a track.
         if (item.track != null) {
@@ -196,7 +196,7 @@ private class AlbumSongViewHolder private constructor(private val binding: ItemA
         binding.root.setOnClickListener { listener.onItemClick(item) }
     }
 
-    override fun updateIndicator(isActive: Boolean, isPlaying: Boolean) {
+    override fun updatePlayingIndicator(isActive: Boolean, isPlaying: Boolean) {
         binding.root.isSelected = isActive
         binding.songTrackBg.isPlaying = isPlaying
     }

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

@@ -29,7 +29,7 @@ import org.oxycblt.auxio.databinding.ItemSongBinding
 import org.oxycblt.auxio.music.Album
 import org.oxycblt.auxio.music.Artist
 import org.oxycblt.auxio.music.Song
-import org.oxycblt.auxio.ui.recycler.IndicatorAdapter
+import org.oxycblt.auxio.ui.recycler.PlayingIndicatorAdapter
 import org.oxycblt.auxio.ui.recycler.Item
 import org.oxycblt.auxio.ui.recycler.MenuItemListener
 import org.oxycblt.auxio.ui.recycler.SimpleItemCallback
@@ -154,7 +154,7 @@ private class ArtistDetailViewHolder private constructor(private val binding: It
 }
 
 private class ArtistAlbumViewHolder private constructor(private val binding: ItemParentBinding) :
-    IndicatorAdapter.ViewHolder(binding.root) {
+    PlayingIndicatorAdapter.ViewHolder(binding.root) {
     fun bind(item: Album, listener: MenuItemListener) {
         binding.parentImage.bind(item)
         binding.parentName.text = item.resolveName(binding.context)
@@ -164,7 +164,7 @@ private class ArtistAlbumViewHolder private constructor(private val binding: Ite
         binding.root.setOnClickListener { listener.onItemClick(item) }
     }
 
-    override fun updateIndicator(isActive: Boolean, isPlaying: Boolean) {
+    override fun updatePlayingIndicator(isActive: Boolean, isPlaying: Boolean) {
         binding.root.isSelected = isActive
         binding.parentImage.isPlaying = isPlaying
     }
@@ -184,7 +184,7 @@ private class ArtistAlbumViewHolder private constructor(private val binding: Ite
 }
 
 private class ArtistSongViewHolder private constructor(private val binding: ItemSongBinding) :
-    IndicatorAdapter.ViewHolder(binding.root) {
+    PlayingIndicatorAdapter.ViewHolder(binding.root) {
     fun bind(item: Song, listener: MenuItemListener) {
         binding.songAlbumCover.bind(item)
         binding.songName.text = item.resolveName(binding.context)
@@ -193,7 +193,7 @@ private class ArtistSongViewHolder private constructor(private val binding: Item
         binding.root.setOnClickListener { listener.onItemClick(item) }
     }
 
-    override fun updateIndicator(isActive: Boolean, isPlaying: Boolean) {
+    override fun updatePlayingIndicator(isActive: Boolean, isPlaying: Boolean) {
         binding.root.isSelected = isActive
         binding.songAlbumCover.isPlaying = isPlaying
     }

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

@@ -29,7 +29,7 @@ import org.oxycblt.auxio.detail.SortHeader
 import org.oxycblt.auxio.ui.recycler.AuxioRecyclerView
 import org.oxycblt.auxio.ui.recycler.Header
 import org.oxycblt.auxio.ui.recycler.HeaderViewHolder
-import org.oxycblt.auxio.ui.recycler.IndicatorAdapter
+import org.oxycblt.auxio.ui.recycler.PlayingIndicatorAdapter
 import org.oxycblt.auxio.ui.recycler.Item
 import org.oxycblt.auxio.ui.recycler.MenuItemListener
 import org.oxycblt.auxio.ui.recycler.SimpleItemCallback
@@ -39,7 +39,7 @@ import org.oxycblt.auxio.util.inflater
 abstract class DetailAdapter<L : DetailAdapter.Listener>(
     private val listener: L,
     diffCallback: DiffUtil.ItemCallback<Item>
-) : IndicatorAdapter<RecyclerView.ViewHolder>(), AuxioRecyclerView.SpanSizeLookup {
+) : PlayingIndicatorAdapter<RecyclerView.ViewHolder>(), AuxioRecyclerView.SpanSizeLookup {
     private var isPlaying = false
 
     @Suppress("LeakingThis") override fun getItemCount() = differ.currentList.size

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

@@ -26,6 +26,7 @@ import org.oxycblt.auxio.home.tabs.Tab
 import org.oxycblt.auxio.music.Album
 import org.oxycblt.auxio.music.Artist
 import org.oxycblt.auxio.music.Genre
+import org.oxycblt.auxio.music.Music
 import org.oxycblt.auxio.music.MusicMode
 import org.oxycblt.auxio.music.MusicStore
 import org.oxycblt.auxio.music.Song

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

@@ -31,7 +31,7 @@ import org.oxycblt.auxio.music.Sort
 import org.oxycblt.auxio.playback.formatDurationMs
 import org.oxycblt.auxio.playback.secsToMs
 import org.oxycblt.auxio.ui.recycler.AlbumViewHolder
-import org.oxycblt.auxio.ui.recycler.IndicatorAdapter
+import org.oxycblt.auxio.ui.recycler.PlayingIndicatorAdapter
 import org.oxycblt.auxio.ui.recycler.Item
 import org.oxycblt.auxio.ui.recycler.MenuItemListener
 import org.oxycblt.auxio.ui.recycler.SyncListDiffer
@@ -117,7 +117,7 @@ class AlbumListFragment : HomeListFragment<Album>() {
     }
 
     private class AlbumAdapter(private val listener: MenuItemListener) :
-        IndicatorAdapter<AlbumViewHolder>() {
+        PlayingIndicatorAdapter<AlbumViewHolder>() {
         private val differ = SyncListDiffer(this, AlbumViewHolder.DIFFER)
 
         override val currentList: List<Item>

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

@@ -28,7 +28,7 @@ import org.oxycblt.auxio.music.MusicParent
 import org.oxycblt.auxio.music.Sort
 import org.oxycblt.auxio.playback.formatDurationMs
 import org.oxycblt.auxio.ui.recycler.ArtistViewHolder
-import org.oxycblt.auxio.ui.recycler.IndicatorAdapter
+import org.oxycblt.auxio.ui.recycler.PlayingIndicatorAdapter
 import org.oxycblt.auxio.ui.recycler.Item
 import org.oxycblt.auxio.ui.recycler.MenuItemListener
 import org.oxycblt.auxio.ui.recycler.SyncListDiffer
@@ -93,7 +93,7 @@ class ArtistListFragment : HomeListFragment<Artist>() {
     }
 
     private class ArtistAdapter(private val listener: MenuItemListener) :
-        IndicatorAdapter<ArtistViewHolder>() {
+        PlayingIndicatorAdapter<ArtistViewHolder>() {
         private val differ = SyncListDiffer(this, ArtistViewHolder.DIFFER)
 
         override val currentList: List<Item>

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

@@ -28,7 +28,7 @@ import org.oxycblt.auxio.music.MusicParent
 import org.oxycblt.auxio.music.Sort
 import org.oxycblt.auxio.playback.formatDurationMs
 import org.oxycblt.auxio.ui.recycler.GenreViewHolder
-import org.oxycblt.auxio.ui.recycler.IndicatorAdapter
+import org.oxycblt.auxio.ui.recycler.PlayingIndicatorAdapter
 import org.oxycblt.auxio.ui.recycler.Item
 import org.oxycblt.auxio.ui.recycler.MenuItemListener
 import org.oxycblt.auxio.ui.recycler.SyncListDiffer
@@ -92,7 +92,7 @@ class GenreListFragment : HomeListFragment<Genre>() {
     }
 
     private class GenreAdapter(private val listener: MenuItemListener) :
-        IndicatorAdapter<GenreViewHolder>() {
+        PlayingIndicatorAdapter<GenreViewHolder>() {
         private val differ = SyncListDiffer(this, GenreViewHolder.DIFFER)
 
         override val currentList: List<Item>

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

@@ -31,7 +31,7 @@ import org.oxycblt.auxio.music.Sort
 import org.oxycblt.auxio.playback.formatDurationMs
 import org.oxycblt.auxio.playback.secsToMs
 import org.oxycblt.auxio.settings.Settings
-import org.oxycblt.auxio.ui.recycler.IndicatorAdapter
+import org.oxycblt.auxio.ui.recycler.PlayingIndicatorAdapter
 import org.oxycblt.auxio.ui.recycler.Item
 import org.oxycblt.auxio.ui.recycler.MenuItemListener
 import org.oxycblt.auxio.ui.recycler.SongViewHolder
@@ -129,7 +129,7 @@ class SongListFragment : HomeListFragment<Song>() {
     }
 
     private class SongAdapter(private val listener: MenuItemListener) :
-        IndicatorAdapter<SongViewHolder>() {
+        PlayingIndicatorAdapter<SongViewHolder>() {
         private val differ = SyncListDiffer(this, SongViewHolder.DIFFER)
 
         override val currentList: List<Item>

app/src/main/java/org/oxycblt/auxio/image/ImageGroup.kt

@@ -40,8 +40,8 @@ import org.oxycblt.auxio.util.getDimenSize
  * Effectively a super-charged [StyledImageView].
  *
  * This class enables the following features alongside the base features pf [StyledImageView]:
- * - Activation indicator
+ * - Selection indicator
- * - (Eventually) selection indicator
+ * - (Eventually) activation indicator
  * - Support for ONE custom view
  *
  * This class is primarily intended for list items. For most uses, the simpler [StyledImageView] is

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

@@ -28,7 +28,7 @@ import com.google.android.material.shape.MaterialShapeDrawable
 import org.oxycblt.auxio.R
 import org.oxycblt.auxio.databinding.ItemQueueSongBinding
 import org.oxycblt.auxio.music.Song
-import org.oxycblt.auxio.ui.recycler.IndicatorAdapter
+import org.oxycblt.auxio.ui.recycler.PlayingIndicatorAdapter
 import org.oxycblt.auxio.ui.recycler.SongViewHolder
 import org.oxycblt.auxio.ui.recycler.SyncListDiffer
 import org.oxycblt.auxio.util.context
@@ -60,7 +60,7 @@ class QueueAdapter(private val listener: QueueItemListener) :
         }
 
         viewHolder.isEnabled = position > currentIndex
-        viewHolder.updateIndicator(position == currentIndex, isPlaying)
+        viewHolder.updatePlayingIndicator(position == currentIndex, isPlaying)
     }
 
     fun submitList(newList: List<Song>) {
@@ -110,7 +110,7 @@ interface QueueItemListener {
 }
 
 class QueueSongViewHolder private constructor(private val binding: ItemQueueSongBinding) :
-    IndicatorAdapter.ViewHolder(binding.root) {
+    PlayingIndicatorAdapter.ViewHolder(binding.root) {
     val bodyView: View
         get() = binding.body
     val backgroundView: View
@@ -164,7 +164,7 @@ class QueueSongViewHolder private constructor(private val binding: ItemQueueSong
             binding.songDragHandle.isEnabled = value
         }
 
-    override fun updateIndicator(isActive: Boolean, isPlaying: Boolean) {
+    override fun updatePlayingIndicator(isActive: Boolean, isPlaying: Boolean) {
         binding.interactBody.isSelected = isActive
         binding.songAlbumCover.isPlaying = isPlaying
     }

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

@@ -30,14 +30,14 @@ import org.oxycblt.auxio.ui.recycler.AuxioRecyclerView
 import org.oxycblt.auxio.ui.recycler.GenreViewHolder
 import org.oxycblt.auxio.ui.recycler.Header
 import org.oxycblt.auxio.ui.recycler.HeaderViewHolder
-import org.oxycblt.auxio.ui.recycler.IndicatorAdapter
+import org.oxycblt.auxio.ui.recycler.PlayingIndicatorAdapter
 import org.oxycblt.auxio.ui.recycler.Item
 import org.oxycblt.auxio.ui.recycler.MenuItemListener
 import org.oxycblt.auxio.ui.recycler.SimpleItemCallback
 import org.oxycblt.auxio.ui.recycler.SongViewHolder
 
 class SearchAdapter(private val listener: MenuItemListener) :
-    IndicatorAdapter<RecyclerView.ViewHolder>(), AuxioRecyclerView.SpanSizeLookup {
+    PlayingIndicatorAdapter<RecyclerView.ViewHolder>(), AuxioRecyclerView.SpanSizeLookup {
     private val differ = AsyncListDiffer(this, DIFFER)
 
     override fun getItemCount() = differ.currentList.size

app/src/main/java/org/oxycblt/auxio/ui/recycler/Adapters.kt

@@ -19,6 +19,7 @@ package org.oxycblt.auxio.ui.recycler
 
 import android.view.View
 import androidx.recyclerview.widget.RecyclerView
+import org.oxycblt.auxio.music.Music
 import org.oxycblt.auxio.util.logW
 
 /**
@@ -27,7 +28,7 @@ import org.oxycblt.auxio.util.logW
  * itself.
  * @author OxygenCobalt
  */
-abstract class IndicatorAdapter<VH : RecyclerView.ViewHolder> : RecyclerView.Adapter<VH>() {
+abstract class PlayingIndicatorAdapter<VH : RecyclerView.ViewHolder> : RecyclerView.Adapter<VH>() {
     private var isPlaying = false
     private var currentItem: Item? = null
 
@@ -37,7 +38,7 @@ abstract class IndicatorAdapter<VH : RecyclerView.ViewHolder> : RecyclerView.Ada
         if (holder is ViewHolder) {
             val item = currentList[position]
             val currentItem = currentItem
-            holder.updateIndicator(item == currentItem, isPlaying)
+            holder.updatePlayingIndicator(item == currentItem, isPlaying)
         }
     }
 
@@ -92,20 +93,8 @@ abstract class IndicatorAdapter<VH : RecyclerView.ViewHolder> : RecyclerView.Ada
         val PAYLOAD_INDICATOR_CHANGED = Any()
     }
 
-    /** A ViewHolder that can respond to indicator updates. */
+    /** A ViewHolder that can respond to playing ]indicator updates. */
     abstract class ViewHolder(root: View) : RecyclerView.ViewHolder(root) {
-        abstract fun updateIndicator(isActive: Boolean, isPlaying: Boolean)
+        abstract fun updatePlayingIndicator(isActive: Boolean, isPlaying: Boolean)
-    }
-}
-
-/**
- * ViewHolder that correctly resizes the item to match the parent width, which it is not normally.
- */
-abstract class DialogViewHolder(root: View) : RecyclerView.ViewHolder(root) {
-    init {
-        // Actually make the item full-width, which it won't be in dialogs
-        root.layoutParams =
-            RecyclerView.LayoutParams(
-                RecyclerView.LayoutParams.MATCH_PARENT, RecyclerView.LayoutParams.WRAP_CONTENT)
     }
 }

app/src/main/java/org/oxycblt/auxio/ui/recycler/DialogRecyclerView.kt

@@ -19,6 +19,7 @@ package org.oxycblt.auxio.ui.recycler
 
 import android.content.Context
 import android.util.AttributeSet
+import android.view.View
 import android.view.ViewGroup
 import androidx.annotation.AttrRes
 import androidx.core.view.isInvisible
@@ -93,3 +94,16 @@ constructor(context: Context, attrs: AttributeSet? = null, @AttrRes defStyleAttr
             manager.findLastCompletelyVisibleItemPosition() == (manager.itemCount - 1)
     }
 }
+
+/**
+ * ViewHolder that correctly resizes the item to match the parent width, which it is not normally
+ * in dialogs.
+ */
+abstract class DialogViewHolder(root: View) : RecyclerView.ViewHolder(root) {
+    init {
+        // Actually make the item full-width, which it won't be in dialogs
+        root.layoutParams =
+            RecyclerView.LayoutParams(
+                RecyclerView.LayoutParams.MATCH_PARENT, RecyclerView.LayoutParams.WRAP_CONTENT)
+    }
+}

app/src/main/java/org/oxycblt/auxio/ui/recycler/SelectionIndicatorAdapter.kt

@@ -0,0 +1,53 @@
+package org.oxycblt.auxio.ui.recycler
+
+import android.view.View
+import androidx.recyclerview.widget.RecyclerView
+import org.oxycblt.auxio.music.Music
+
+/**
+ * An adapter that implements selection indicators.
+ * @author OxygenCobalt
+ */
+abstract class SelectionIndicatorAdapter<VH : RecyclerView.ViewHolder> : PlayingIndicatorAdapter<VH>() {
+    private var selectedItems = setOf<Music>()
+
+    override fun onBindViewHolder(
+        holder: VH,
+        position: Int,
+        payloads: List<Any>
+    ) {
+        super.onBindViewHolder(holder, position, payloads)
+
+        if (holder is ViewHolder) {
+            holder.updateSelectionIndicator(selectedItems.contains(currentList[position]))
+        }
+    }
+
+    fun updateSelection(items: Set<Music>) {
+        val oldSelectedItems = selectedItems
+
+        if (items == oldSelectedItems) {
+            return
+        }
+
+        selectedItems = items
+        for (i in currentList.indices) {
+            // TODO: Perhaps add an optimization that allows me to avoid the O(n) iteration
+            //  assuming all list items are unique?
+            val item = currentList[i]
+            if (item !is Music) {
+                continue
+            }
+
+            if (oldSelectedItems.contains(item) || items.contains(item)) {
+                notifyItemChanged(i, PAYLOAD_INDICATOR_CHANGED)
+            }
+        }
+    }
+
+    /** A ViewHolder that can respond to selection indicator updates. */
+    abstract class ViewHolder(root: View) : RecyclerView.ViewHolder(root) {
+        abstract fun updateSelectionIndicator(isSelected: Boolean)
+    }
+}
+

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

@@ -37,7 +37,7 @@ import org.oxycblt.auxio.util.inflater
  * @author OxygenCobalt
  */
 class SongViewHolder private constructor(private val binding: ItemSongBinding) :
-    IndicatorAdapter.ViewHolder(binding.root) {
+    PlayingIndicatorAdapter.ViewHolder(binding.root) {
     fun bind(item: Song, listener: MenuItemListener) {
         binding.songAlbumCover.bind(item)
         binding.songName.text = item.resolveName(binding.context)
@@ -46,7 +46,7 @@ class SongViewHolder private constructor(private val binding: ItemSongBinding) :
         binding.root.setOnClickListener { listener.onItemClick(item) }
     }
 
-    override fun updateIndicator(isActive: Boolean, isPlaying: Boolean) {
+    override fun updatePlayingIndicator(isActive: Boolean, isPlaying: Boolean) {
         binding.root.isSelected = isActive
         binding.songAlbumCover.isPlaying = isPlaying
     }
@@ -69,7 +69,7 @@ class SongViewHolder private constructor(private val binding: ItemSongBinding) :
  * @author OxygenCobalt
  */
 class AlbumViewHolder private constructor(private val binding: ItemParentBinding) :
-    IndicatorAdapter.ViewHolder(binding.root) {
+    PlayingIndicatorAdapter.ViewHolder(binding.root) {
 
     fun bind(item: Album, listener: MenuItemListener) {
         binding.parentImage.bind(item)
@@ -79,7 +79,7 @@ class AlbumViewHolder private constructor(private val binding: ItemParentBinding
         binding.root.setOnClickListener { listener.onItemClick(item) }
     }
 
-    override fun updateIndicator(isActive: Boolean, isPlaying: Boolean) {
+    override fun updatePlayingIndicator(isActive: Boolean, isPlaying: Boolean) {
         binding.root.isSelected = isActive
         binding.parentImage.isPlaying = isPlaying
     }
@@ -104,7 +104,7 @@ class AlbumViewHolder private constructor(private val binding: ItemParentBinding
  * @author OxygenCobalt
  */
 class ArtistViewHolder private constructor(private val binding: ItemParentBinding) :
-    IndicatorAdapter.ViewHolder(binding.root) {
+    PlayingIndicatorAdapter.ViewHolder(binding.root) {
 
     fun bind(item: Artist, listener: MenuItemListener) {
         binding.parentImage.bind(item)
@@ -125,7 +125,7 @@ class ArtistViewHolder private constructor(private val binding: ItemParentBindin
         binding.root.setOnClickListener { listener.onItemClick(item) }
     }
 
-    override fun updateIndicator(isActive: Boolean, isPlaying: Boolean) {
+    override fun updatePlayingIndicator(isActive: Boolean, isPlaying: Boolean) {
         binding.root.isSelected = isActive
         binding.parentImage.isPlaying = isPlaying
     }
@@ -150,7 +150,7 @@ class ArtistViewHolder private constructor(private val binding: ItemParentBindin
  * @author OxygenCobalt
  */
 class GenreViewHolder private constructor(private val binding: ItemParentBinding) :
-    IndicatorAdapter.ViewHolder(binding.root) {
+    PlayingIndicatorAdapter.ViewHolder(binding.root) {
 
     fun bind(item: Genre, listener: MenuItemListener) {
         binding.parentImage.bind(item)
@@ -164,7 +164,7 @@ class GenreViewHolder private constructor(private val binding: ItemParentBinding
         binding.root.setOnClickListener { listener.onItemClick(item) }
     }
 
-    override fun updateIndicator(isActive: Boolean, isPlaying: Boolean) {
+    override fun updatePlayingIndicator(isActive: Boolean, isPlaying: Boolean) {
         binding.root.isSelected = isActive
         binding.parentImage.isPlaying = isPlaying
     }