queue: rework previous items

Rework previous items to be based off of adapter state.

This improves the transitions between active and previous items and
their overall efficiency.

app/src/main/java/com/google/android/material/bottomsheet/NeoBottomSheetBehavior.java

@@ -720,7 +720,8 @@ public class NeoBottomSheetBehavior<V extends View> extends CoordinatorLayout.Be
       }
     } else if (dy < 0) { // Downward
       if (!target.canScrollVertically(-1)) {
-        if (newTop <= collapsedOffset || hideable) {
+        // MODIFICATION: Add enableHidingGestures method
+        if (newTop <= collapsedOffset || (hideable && enableHidingGestures())) {
           if (!draggable) {
             // Prevent dragging
             return;
@@ -774,7 +775,8 @@ public class NeoBottomSheetBehavior<V extends View> extends CoordinatorLayout.Be
           }
         }
       }
-    } else if (hideable && shouldHide(child, getYVelocity())) {
+      // MODIFICATION: Add enableHidingGestures method
+    } else if (hideable && shouldHide(child, getYVelocity()) && enableHidingGestures()) {
       targetState = STATE_HIDDEN;
     } else if (lastNestedScrollDy == 0) {
       int currentTop = child.getTop();
@@ -1723,7 +1725,8 @@ public class NeoBottomSheetBehavior<V extends View> extends CoordinatorLayout.Be
                 }
               }
             }
-          } else if (hideable && shouldHide(releasedChild, yvel)) {
+            // MODIFICATION: Add enableHidingGestures method
+          } else if (hideable && shouldHide(releasedChild, yvel) && enableHidingGestures()) {
             // Hide if the view was either released low or it was a significant vertical swipe
             // otherwise settle to closest expanded state.
             if ((Math.abs(xvel) < Math.abs(yvel) && yvel > SIGNIFICANT_VEL_THRESHOLD)
@@ -1795,8 +1798,9 @@ public class NeoBottomSheetBehavior<V extends View> extends CoordinatorLayout.Be
 
         @Override
         public int clampViewPositionVertical(@NonNull View child, int top, int dy) {
+          // MODIFICATION: Add enableHidingGestures method
           return MathUtils.clamp(
-              top, getExpandedOffset(), hideable ? parentHeight : collapsedOffset);
+              top, getExpandedOffset(), (hideable && enableHidingGestures()) ? parentHeight : collapsedOffset);
         }
 
         @Override
@@ -1806,7 +1810,8 @@ public class NeoBottomSheetBehavior<V extends View> extends CoordinatorLayout.Be
 
         @Override
         public int getViewVerticalDragRange(@NonNull View child) {
-          if (hideable) {
+          // MODIFICATION: Add enableHidingGestures method
+          if (hideable && enableHidingGestures()) {
             return parentHeight;
           } else {
             return collapsedOffset;
@@ -1876,6 +1881,15 @@ public class NeoBottomSheetBehavior<V extends View> extends CoordinatorLayout.Be
     return true;
   }
 
+  /**
+   * Checks whether hiding gestures should be enabled if {@code isHideable} is true.
+   * @hide
+   */
+  @RestrictTo(LIBRARY_GROUP)
+  public boolean enableHidingGestures() {
+    return true;
+  }
+
   /**
    * Checks whether the bottom sheet should be expanded after it has been released after dragging.
    *

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

@@ -68,6 +68,9 @@ class PlaybackSheetBehavior<V : View>(context: Context, attributeSet: AttributeS
         return success
     }
 
+    // Note: This is an extension to Auxio's vendored BottomSheetBehavior
+    override fun enableHidingGestures() = true
+
     fun hideSafe() {
         if (state != STATE_HIDDEN) {
             isDraggable = false

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

@@ -29,13 +29,46 @@ import java.util.*
 import org.oxycblt.auxio.IntegerTable
 import org.oxycblt.auxio.R
 import org.oxycblt.auxio.databinding.ItemQueueSongBinding
+import org.oxycblt.auxio.music.Song
 import org.oxycblt.auxio.ui.recycler.*
 import org.oxycblt.auxio.util.*
 
 class QueueAdapter(listener: QueueItemListener) :
-    MonoAdapter<QueueViewModel.QueueSong, QueueItemListener, QueueSongViewHolder>(listener) {
+    MonoAdapter<Song, QueueItemListener, QueueSongViewHolder>(listener) {
+    private var currentIndex = 0
+
     override val data = SyncBackingData(this, QueueSongViewHolder.DIFFER)
     override val creator = QueueSongViewHolder.CREATOR
+
+    override fun onBindViewHolder(
+        viewHolder: QueueSongViewHolder,
+        position: Int,
+        payload: List<Any>
+    ) {
+        if (payload.isEmpty()) {
+            super.onBindViewHolder(viewHolder, position, payload)
+        }
+
+        viewHolder.isPrevious = position <= currentIndex
+    }
+
+    fun updateIndex(index: Int) {
+        when {
+            index < currentIndex -> {
+                val lastIndex = currentIndex
+                currentIndex = index
+                notifyItemRangeChanged(0, lastIndex + 1, PAYLOAD_UPDATE_INDEX)
+            }
+            index > currentIndex -> {
+                currentIndex = index
+                notifyItemRangeChanged(0, currentIndex + 1, PAYLOAD_UPDATE_INDEX)
+            }
+        }
+    }
+
+    companion object {
+        val PAYLOAD_UPDATE_INDEX = Any()
+    }
 }
 
 interface QueueItemListener {
@@ -46,7 +79,7 @@ interface QueueItemListener {
 class QueueSongViewHolder
 private constructor(
     private val binding: ItemQueueSongBinding,
-) : BindingViewHolder<QueueViewModel.QueueSong, QueueItemListener>(binding.root) {
+) : BindingViewHolder<Song, QueueItemListener>(binding.root) {
     val bodyView: View
         get() = binding.body
     val backgroundView: View
@@ -58,8 +91,15 @@ private constructor(
             elevation = binding.context.getDimenSafe(R.dimen.elevation_normal) * 5
         }
 
-    val isPrevious: Boolean
+    var isPrevious: Boolean
         get() = binding.songDragHandle.alpha == 0.5f
+        set(value) {
+            val alpha = if (value) 0.5f else 1f
+            binding.songAlbumCover.alpha = alpha
+            binding.songName.alpha = alpha
+            binding.songInfo.alpha = alpha
+            binding.songDragHandle.alpha = alpha
+        }
 
     init {
         binding.body.background =
@@ -75,10 +115,10 @@ private constructor(
     }
 
     @SuppressLint("ClickableViewAccessibility")
-    override fun bind(item: QueueViewModel.QueueSong, listener: QueueItemListener) {
+    override fun bind(item: Song, listener: QueueItemListener) {
-        binding.songAlbumCover.bind(item.song)
+        binding.songAlbumCover.bind(item)
-        binding.songName.textSafe = item.song.resolveName(binding.context)
+        binding.songName.textSafe = item.resolveName(binding.context)
-        binding.songInfo.textSafe = item.song.resolveIndividualArtistName(binding.context)
+        binding.songInfo.textSafe = item.resolveIndividualArtistName(binding.context)
 
         binding.background.isInvisible = true
 
@@ -87,12 +127,6 @@ private constructor(
 
         binding.body.setOnClickListener { listener.onClick(this) }
 
-        val alpha = if (item.previous) 0.5f else 1f
-        binding.songAlbumCover.alpha = alpha
-        binding.songName.alpha = alpha
-        binding.songInfo.alpha = alpha
-        binding.songDragHandle.alpha = alpha
-
         // Roll our own drag handlers as the default ones suck
         binding.songDragHandle.setOnTouchListener { _, motionEvent ->
             binding.songDragHandle.performClick()
@@ -113,19 +147,6 @@ private constructor(
                     QueueSongViewHolder(ItemQueueSongBinding.inflate(context.inflater))
             }
 
-        val DIFFER =
+        val DIFFER = SongViewHolder.DIFFER
-            object : SimpleItemCallback<QueueViewModel.QueueSong>() {
-                override fun areContentsTheSame(
-                    oldItem: QueueViewModel.QueueSong,
-                    newItem: QueueViewModel.QueueSong
-                ) =
-                    super.areContentsTheSame(oldItem, newItem) &&
-                        oldItem.previous == newItem.previous
-
-                override fun areItemsTheSame(
-                    oldItem: QueueViewModel.QueueSong,
-                    newItem: QueueViewModel.QueueSong
-                ) = oldItem.song == newItem.song && oldItem.previous == newItem.previous
-            }
     }
 }

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

@@ -25,10 +25,11 @@ import androidx.fragment.app.activityViewModels
 import androidx.recyclerview.widget.ItemTouchHelper
 import androidx.recyclerview.widget.LinearLayoutManager
 import androidx.recyclerview.widget.RecyclerView
-import java.util.*
 import org.oxycblt.auxio.databinding.FragmentQueueBinding
+import org.oxycblt.auxio.music.Song
 import org.oxycblt.auxio.ui.fragment.ViewBindingFragment
 import org.oxycblt.auxio.util.collectImmediately
+import org.oxycblt.auxio.util.logD
 
 /**
  * A [Fragment] that shows the queue and enables editing as well.
@@ -66,7 +67,7 @@ class QueueFragment : ViewBindingFragment<FragmentQueueBinding>(), QueueItemList
 
         // --- VIEWMODEL SETUP ----
 
-        collectImmediately(queueModel.queue, ::updateQueue)
+        collectImmediately(queueModel.queue, queueModel.index, ::updateQueue)
     }
 
     override fun onDestroyBinding(binding: FragmentQueueBinding) {
@@ -82,16 +83,20 @@ class QueueFragment : ViewBindingFragment<FragmentQueueBinding>(), QueueItemList
         touchHelper.startDrag(viewHolder)
     }
 
-    private fun updateQueue(queue: List<QueueViewModel.QueueSong>) {
+    private fun updateQueue(queue: List<Song>, index: Int) {
-        val instructions = queueModel.instructions
+        val replaceQueue = queueModel.replaceQueue
-        if (instructions != null) {
+        if (replaceQueue == true) {
-            if (instructions.replace) {
+            logD("Replacing queue")
             queueAdapter.data.replaceList(queue)
         } else {
+            logD("Diffing queue")
             queueAdapter.data.submitList(queue)
         }
 
-            if (instructions.scrollTo != null) {
+        queueModel.finishReplace()
+
+        val scrollTo = queueModel.scrollTo
+        if (scrollTo != null) {
             val binding = requireBinding()
             val lmm = binding.queueRecycler.layoutManager as LinearLayoutManager
             val start = lmm.findFirstCompletelyVisibleItemPosition()
@@ -99,14 +104,13 @@ class QueueFragment : ViewBindingFragment<FragmentQueueBinding>(), QueueItemList
 
             if (start != RecyclerView.NO_POSITION &&
                 end != RecyclerView.NO_POSITION &&
-                    instructions.scrollTo !in start..end) {
+                scrollTo !in start..end) {
-                    binding.queueRecycler.scrollToPosition(instructions.scrollTo)
+                binding.queueRecycler.scrollToPosition(scrollTo)
             }
         }
 
-            queueModel.finishInstructions()
+        queueModel.finishScrollTo()
-        } else {
+
-            queueAdapter.data.submitList(queue)
+        queueAdapter.updateIndex(index)
-        }
     }
 }

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

@@ -33,6 +33,7 @@ class QueueSheetBehavior<V : View>(context: Context, attributeSet: AttributeSet?
     private var barSpacing = context.getDimenSizeSafe(R.dimen.spacing_small)
 
     init {
+        isHideable = false
         sheetBackgroundDrawable.setCornerSize(context.getDimenSafe(R.dimen.size_corners_medium))
     }
 

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

@@ -24,21 +24,19 @@ import kotlinx.coroutines.flow.StateFlow
 import org.oxycblt.auxio.music.MusicParent
 import org.oxycblt.auxio.music.Song
 import org.oxycblt.auxio.playback.state.PlaybackStateManager
-import org.oxycblt.auxio.ui.recycler.Item
 
 class QueueViewModel : ViewModel(), PlaybackStateManager.Callback {
     private val playbackManager = PlaybackStateManager.getInstance()
 
-    data class QueueSong(val song: Song, val previous: Boolean) : Item() {
+    private val _queue = MutableStateFlow(listOf<Song>())
-        override val id: Long
+    val queue: StateFlow<List<Song>> = _queue
-            get() = song.id
-    }
 
-    private val _queue = MutableStateFlow(listOf<QueueSong>())
+    private val _index = MutableStateFlow(playbackManager.index)
-    val queue: StateFlow<List<QueueSong>> = _queue
+    val index: StateFlow<Int>
+        get() = _index
 
-    data class QueueInstructions(val replace: Boolean, val scrollTo: Int?)
+    var replaceQueue: Boolean? = null
-    var instructions: QueueInstructions? = null
+    var scrollTo: Int? = null
 
     init {
         playbackManager.addCallback(this)
@@ -76,35 +74,38 @@ class QueueViewModel : ViewModel(), PlaybackStateManager.Callback {
         return true
     }
 
-    fun finishInstructions() {
+    fun finishReplace() {
-        instructions = null
+        replaceQueue = null
+    }
+
+    fun finishScrollTo() {
+        scrollTo = null
     }
 
     override fun onIndexMoved(index: Int) {
-        instructions = QueueInstructions(false, min(index + 1, playbackManager.queue.lastIndex))
+        replaceQueue = null
-        _queue.value = generateQueue(index, playbackManager.queue)
+        scrollTo = min(index + 1, playbackManager.queue.lastIndex)
+        _index.value = index
     }
 
     override fun onQueueChanged(queue: List<Song>) {
-        instructions = QueueInstructions(false, null)
+        replaceQueue = false
-        _queue.value = generateQueue(playbackManager.index, queue)
+        scrollTo = null
+        _queue.value = playbackManager.queue.toMutableList()
     }
 
     override fun onQueueReworked(index: Int, queue: List<Song>) {
-        instructions = QueueInstructions(true, min(index + 1, playbackManager.queue.lastIndex))
+        replaceQueue = true
-        _queue.value = generateQueue(index, queue)
+        scrollTo = min(index + 1, playbackManager.queue.lastIndex)
+        _queue.value = playbackManager.queue.toMutableList()
+        _index.value = index
     }
 
     override fun onNewPlayback(index: Int, queue: List<Song>, parent: MusicParent?) {
-        instructions = QueueInstructions(true, min(index + 1, playbackManager.queue.lastIndex))
+        replaceQueue = true
-        _queue.value = generateQueue(index, queue)
+        scrollTo = min(index + 1, playbackManager.queue.lastIndex)
-    }
+        _queue.value = playbackManager.queue.toMutableList()
-
+        _index.value = index
-    private fun generateQueue(index: Int, queue: List<Song>): List<QueueSong> {
-        val before = queue.slice(0..index).map { QueueSong(it, true) }
-        val after =
-            queue.slice(index + 1..playbackManager.queue.lastIndex).map { QueueSong(it, false) }
-        return before + after
     }
 
     override fun onCleared() {

app/src/main/res/layout-w600dp-land/fragment_playback_panel.xml

@@ -38,8 +38,7 @@
         app:layout_constraintHorizontal_bias="0.5"
         app:layout_constraintStart_toEndOf="@+id/playback_cover"
         app:layout_constraintTop_toBottomOf="@+id/playback_toolbar"
-        app:layout_constraintVertical_chainStyle="packed"
+        app:layout_constraintVertical_chainStyle="packed">
-        app:trackColorInactive="@color/sel_track">
 
         <TextView
             android:id="@+id/playback_song"

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

@@ -87,8 +87,7 @@
                         android:indeterminate="true"
                         app:indeterminateAnimationType="disjoint"
                         app:layout_constraintBottom_toBottomOf="@+id/home_indexing_action"
-                        app:layout_constraintTop_toTopOf="@+id/home_indexing_action"
+                        app:layout_constraintTop_toTopOf="@+id/home_indexing_action" />
-                        app:trackColor="@color/sel_track" />
 
                     <Button
                         android:id="@+id/home_indexing_action"