home: add selection framework

Add the basic selection flow to the home UI.

This has no function yet. Further work needs to be done first.

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

@@ -18,9 +18,11 @@
 package org.oxycblt.auxio.home
 
 import android.app.Application
+import androidx.collection.arraySetOf
 import androidx.lifecycle.AndroidViewModel
 import kotlinx.coroutines.flow.MutableStateFlow
 import kotlinx.coroutines.flow.StateFlow
+import kotlinx.coroutines.flow.getAndUpdate
 import org.oxycblt.auxio.R
 import org.oxycblt.auxio.home.tabs.Tab
 import org.oxycblt.auxio.music.Album
@@ -60,6 +62,10 @@ class HomeViewModel(application: Application) :
     val genres: StateFlow<List<Genre>>
         get() = _genres
 
+    private val _selected = MutableStateFlow(listOf<Music>())
+    val selected: StateFlow<List<Music>>
+        get() = _selected
+
     var tabs: List<MusicMode> = visibleTabs
         private set
 
@@ -84,6 +90,19 @@ class HomeViewModel(application: Application) :
         musicStore.addCallback(this)
     }
 
+    /** Select a music item. */
+    fun select(item: Music) {
+        val items = _selected.value.toMutableList()
+        if (items.remove(item)) {
+            logD("Unselecting item $item")
+            _selected.value = items
+        } else {
+            logD("Selecting item $item")
+            items.add(item)
+            _selected.value = items
+        }
+    }
+
     /** Update the current tab based off of the new ViewPager position. */
     fun updateCurrentTab(pos: Int) {
         logD("Updating current tab to ${tabs[pos]}")

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

@@ -25,6 +25,7 @@ import java.util.Formatter
 import org.oxycblt.auxio.R
 import org.oxycblt.auxio.databinding.FragmentHomeListBinding
 import org.oxycblt.auxio.music.Album
+import org.oxycblt.auxio.music.Music
 import org.oxycblt.auxio.music.MusicMode
 import org.oxycblt.auxio.music.MusicParent
 import org.oxycblt.auxio.music.Sort
@@ -97,9 +98,9 @@ class AlbumListFragment : HomeListFragment<Album>() {
         }
     }
 
-    override fun onItemClick(item: Item) {
+    override fun onItemClick(music: Music) {
-        check(item is Album) { "Unexpected datatype: ${item::class.java}" }
+        check(music is Album) { "Unexpected datatype: ${music::class.java}" }
-        navModel.exploreNavigateTo(item)
+        navModel.exploreNavigateTo(music)
     }
 
     override fun onOpenMenu(item: Item, anchor: View) {

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

@@ -23,6 +23,7 @@ import android.view.ViewGroup
 import org.oxycblt.auxio.R
 import org.oxycblt.auxio.databinding.FragmentHomeListBinding
 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.music.Sort
@@ -73,9 +74,9 @@ class ArtistListFragment : HomeListFragment<Artist>() {
         }
     }
 
-    override fun onItemClick(item: Item) {
+    override fun onItemClick(music: Music) {
-        check(item is Artist) { "Unexpected datatype: ${item::class.java}" }
+        check(music is Artist) { "Unexpected datatype: ${music::class.java}" }
-        navModel.exploreNavigateTo(item)
+        navModel.exploreNavigateTo(music)
     }
 
     override fun onOpenMenu(item: Item, anchor: View) {

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

@@ -23,6 +23,7 @@ import android.view.ViewGroup
 import org.oxycblt.auxio.R
 import org.oxycblt.auxio.databinding.FragmentHomeListBinding
 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.music.Sort
@@ -72,9 +73,9 @@ class GenreListFragment : HomeListFragment<Genre>() {
         }
     }
 
-    override fun onItemClick(item: Item) {
+    override fun onItemClick(music: Music) {
-        check(item is Genre) { "Unexpected datatype: ${item::class.java}" }
+        check(music is Genre) { "Unexpected datatype: ${music::class.java}" }
-        navModel.exploreNavigateTo(item)
+        navModel.exploreNavigateTo(music)
     }
 
     override fun onOpenMenu(item: Item, anchor: View) {

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

@@ -22,6 +22,8 @@ import android.view.LayoutInflater
 import androidx.fragment.app.Fragment
 import org.oxycblt.auxio.databinding.FragmentHomeListBinding
 import org.oxycblt.auxio.home.HomeViewModel
+import org.oxycblt.auxio.music.Music
+import org.oxycblt.auxio.music.MusicMode
 import org.oxycblt.auxio.ui.fastscroll.FastScrollRecyclerView
 import org.oxycblt.auxio.ui.fragment.MenuFragment
 import org.oxycblt.auxio.ui.recycler.Item
@@ -63,4 +65,25 @@ abstract class HomeListFragment<T : Item> :
     override fun onFastScrollStop() {
         homeModel.updateFastScrolling(false)
     }
+
+    abstract fun onItemClick(music: Music)
+
+    override fun onItemClick(item: Item) {
+        check(item is Music) { "Unexpected datatype: ${item::class.java}" }
+        if(homeModel.selected.value.isEmpty()) {
+            onItemClick(item)
+        } else {
+            homeModel.select(item)
+        }
+    }
+
+    override fun onItemLongClick(item: Item) {
+        check(item is Music) { "Unexpected datatype: ${item::class.java}" }
+        if (homeModel.selected.value.isEmpty()) {
+            homeModel.select(item)
+        } else {
+            onItemClick(item)
+        }
+    }
+
 }

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

@@ -24,6 +24,7 @@ import android.view.ViewGroup
 import java.util.Formatter
 import org.oxycblt.auxio.R
 import org.oxycblt.auxio.databinding.FragmentHomeListBinding
+import org.oxycblt.auxio.music.Music
 import org.oxycblt.auxio.music.MusicMode
 import org.oxycblt.auxio.music.MusicParent
 import org.oxycblt.auxio.music.Song
@@ -34,6 +35,7 @@ import org.oxycblt.auxio.settings.Settings
 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.SelectionIndicatorAdapter
 import org.oxycblt.auxio.ui.recycler.SongViewHolder
 import org.oxycblt.auxio.ui.recycler.SyncListDiffer
 import org.oxycblt.auxio.util.collectImmediately
@@ -58,6 +60,7 @@ class SongListFragment : HomeListFragment<Song>() {
         }
 
         collectImmediately(homeModel.songs, homeAdapter::replaceList)
+        collectImmediately(homeModel.selected, homeAdapter::updateSelection)
         collectImmediately(
             playbackModel.song, playbackModel.parent, playbackModel.isPlaying, ::handlePlayback)
     }
@@ -104,12 +107,12 @@ class SongListFragment : HomeListFragment<Song>() {
         }
     }
 
-    override fun onItemClick(item: Item) {
+    override fun onItemClick(music: Music) {
-        check(item is Song) { "Unexpected datatype: ${item::class.java}" }
+        check(music is Song) { "Unexpected datatype: ${music::class.java}" }
         when (settings.libPlaybackMode) {
-            MusicMode.SONGS -> playbackModel.playFromAll(item)
+            MusicMode.SONGS -> playbackModel.playFromAll(music)
-            MusicMode.ALBUMS -> playbackModel.playFromAlbum(item)
+            MusicMode.ALBUMS -> playbackModel.playFromAlbum(music)
-            MusicMode.ARTISTS -> playbackModel.playFromArtist(item)
+            MusicMode.ARTISTS -> playbackModel.playFromArtist(music)
             else -> error("Unexpected playback mode: ${settings.libPlaybackMode}")
         }
     }
@@ -129,7 +132,7 @@ class SongListFragment : HomeListFragment<Song>() {
     }
 
     private class SongAdapter(private val listener: MenuItemListener) :
-        PlayingIndicatorAdapter<SongViewHolder>() {
+        SelectionIndicatorAdapter<SongViewHolder>() {
         private val differ = SyncListDiffer(this, SongViewHolder.DIFFER)
 
         override val currentList: List<Item>

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

@@ -40,6 +40,9 @@ interface ItemClickListener {
 
 /** An interface for detecting if an item has had it's menu opened. */
 interface MenuItemListener : ItemClickListener {
+    /** Called when an item is long-clicked. */
+    fun onItemLongClick(item: Item) {}
+
     /** Called when an item desires to open a menu relating to it. */
     fun onOpenMenu(item: Item, anchor: View)
 }

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

@@ -3,6 +3,7 @@ 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.logD
 
 /**
  * An adapter that implements selection indicators.
@@ -23,14 +24,14 @@ abstract class SelectionIndicatorAdapter<VH : RecyclerView.ViewHolder> : Playing
         }
     }
 
-    fun updateSelection(items: Set<Music>) {
+    fun updateSelection(items: List<Music>) {
         val oldSelectedItems = selectedItems
-
+        val newSelectedItems = items.toSet()
-        if (items == oldSelectedItems) {
+        if (newSelectedItems == oldSelectedItems) {
             return
         }
 
-        selectedItems = items
+        selectedItems = newSelectedItems
         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?
@@ -39,14 +40,16 @@ abstract class SelectionIndicatorAdapter<VH : RecyclerView.ViewHolder> : Playing
                 continue
             }
 
-            if (oldSelectedItems.contains(item) || items.contains(item)) {
+            val added = !oldSelectedItems.contains(item) && newSelectedItems.contains(item)
+            val removed = oldSelectedItems.contains(item) && !newSelectedItems.contains(item)
+            if (added || removed) {
                 notifyItemChanged(i, PAYLOAD_INDICATOR_CHANGED)
             }
         }
     }
 
     /** A ViewHolder that can respond to selection indicator updates. */
-    abstract class ViewHolder(root: View) : RecyclerView.ViewHolder(root) {
+    abstract class ViewHolder(root: View) : PlayingIndicatorAdapter.ViewHolder(root) {
         abstract fun updateSelectionIndicator(isSelected: Boolean)
     }
 }

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

@@ -31,17 +31,19 @@ import org.oxycblt.auxio.music.Song
 import org.oxycblt.auxio.util.context
 import org.oxycblt.auxio.util.getPlural
 import org.oxycblt.auxio.util.inflater
+import org.oxycblt.auxio.util.logD
 
 /**
  * The shared ViewHolder for a [Song].
  * @author OxygenCobalt
  */
 class SongViewHolder private constructor(private val binding: ItemSongBinding) :
-    PlayingIndicatorAdapter.ViewHolder(binding.root) {
+    SelectionIndicatorAdapter.ViewHolder(binding.root) {
     fun bind(item: Song, listener: MenuItemListener) {
         binding.songAlbumCover.bind(item)
         binding.songName.text = item.resolveName(binding.context)
         binding.songInfo.text = item.resolveArtistContents(binding.context)
+
         binding.songMenu.setOnClickListener { listener.onOpenMenu(item, it) }
         binding.root.setOnClickListener { listener.onItemClick(item) }
     }
@@ -51,6 +53,11 @@ class SongViewHolder private constructor(private val binding: ItemSongBinding) :
         binding.songAlbumCover.isPlaying = isPlaying
     }
 
+    override fun updateSelectionIndicator(isSelected: Boolean) {
+        logD("Selected")
+        binding.root.isActivated = isSelected
+    }
+
     companion object {
         const val VIEW_TYPE = IntegerTable.VIEW_TYPE_SONG