Add ability to edit queue

Add the [somewhat rough] ability to move/remove items from the queue.

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

@@ -20,7 +20,7 @@ import org.oxycblt.auxio.theme.disable
 import org.oxycblt.auxio.theme.enable
 import org.oxycblt.auxio.theme.toColor
 
-// TODO: Possibly add some swipe-to-next-track function, could require a ViewPager.
+// TODO: Add a swipe-to-next-track function using a ViewPager
 class PlaybackFragment : Fragment(), SeekBar.OnSeekBarChangeListener {
     private val playbackModel: PlaybackViewModel by activityViewModels()
 

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

@@ -15,7 +15,7 @@ import org.oxycblt.auxio.music.toDuration
 import kotlin.random.Random
 import kotlin.random.Random.Default.nextLong
 
-// TODO: Queue
+// TODO: Editing/Adding to Queue
 // TODO: Add the playback service itself
 // TODO: Add loop control [From playback]
 // TODO: Implement persistence through Bundles [I want to keep my shuffles, okay?]
@@ -237,8 +237,7 @@ class PlaybackViewModel : ViewModel() {
 
         updatePlayback(mQueue.value!![mCurrentIndex.value!!])
 
-        // Force the observers to actually update.
+        forceQueueUpdate()
-        mQueue.value = mQueue.value
     }
 
     // Skip to last song
@@ -249,14 +248,61 @@ class PlaybackViewModel : ViewModel() {
 
         updatePlayback(mQueue.value!![mCurrentIndex.value!!])
 
-        // Force the observers to actually update.
+        forceQueueUpdate()
-        mQueue.value = mQueue.value
     }
 
     fun resetAnimStatus() {
         mCanAnimate = false
     }
 
+    // Move two queue items. Called by QueueDragCallback.
+    fun moveQueueItems(adapterFrom: Int, adapterTo: Int) {
+        // Translate the adapter indices into the correct queue indices
+        val delta = mQueue.value!!.size - formattedQueue.value!!.size
+
+        val from = adapterFrom + delta
+        val to = adapterTo + delta
+
+        try {
+            val currentItem = mQueue.value!![from]
+            val targetItem = mQueue.value!![to]
+
+            // Then swap the items manually since kotlin does have a swap function.
+            mQueue.value!![to] = currentItem
+            mQueue.value!![from] = targetItem
+        } catch (exception: IndexOutOfBoundsException) {
+            Log.e(this::class.simpleName, "Indices were out of bounds, did not swap queue items")
+
+            return
+        }
+
+        forceQueueUpdate()
+    }
+
+    // Remove a queue item. Called by QueueDragCallback.
+    fun removeQueueItem(adapterIndex: Int) {
+        // Translate the adapter index into the correct queue index
+        val delta = mQueue.value!!.size - formattedQueue.value!!.size
+        val properIndex = adapterIndex + delta
+
+        Log.d(this::class.simpleName, "Removing item ${mQueue.value!![properIndex].name}.")
+
+        if (properIndex > mQueue.value!!.size || properIndex < 0) {
+            Log.e(this::class.simpleName, "Index is out of bounds, did not remove queue item.")
+
+            return
+        }
+
+        mQueue.value!!.removeAt(properIndex)
+
+        forceQueueUpdate()
+    }
+
+    // Force the observers of the queue to actually update after making changes.
+    private fun forceQueueUpdate() {
+        mQueue.value = mQueue.value
+    }
+
     // Generic function for updating the playback with a new song.
     // Use this instead of manually updating the values each time.
     private fun updatePlayback(song: Song) {

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

@@ -1,20 +1,49 @@
 package org.oxycblt.auxio.playback.queue
 
+import android.annotation.SuppressLint
+import android.view.LayoutInflater
+import android.view.MotionEvent
 import android.view.ViewGroup
+import androidx.recyclerview.widget.ItemTouchHelper
 import androidx.recyclerview.widget.ListAdapter
+import org.oxycblt.auxio.databinding.ItemQueueSongBinding
 import org.oxycblt.auxio.music.Song
 import org.oxycblt.auxio.recycler.DiffCallback
-import org.oxycblt.auxio.recycler.viewholders.SongViewHolder
+import org.oxycblt.auxio.recycler.viewholders.BaseViewHolder
 
-class QueueAdapter(
+// FIXME: Build a Diff function so that QueueAdapter doesn't scroll wildly when things are moved
-    private val doOnClick: (Song) -> Unit
+class QueueAdapter(private val dragCallback: ItemTouchHelper) :
-) : ListAdapter<Song, SongViewHolder>(DiffCallback<Song>()) {
+    ListAdapter<Song, QueueAdapter.ViewHolder>(DiffCallback<Song>()) {
 
-    override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): SongViewHolder {
+    override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): ViewHolder {
-        return SongViewHolder.from(parent.context, doOnClick)
+        return ViewHolder(ItemQueueSongBinding.inflate(LayoutInflater.from(parent.context)))
     }
 
-    override fun onBindViewHolder(holder: SongViewHolder, position: Int) {
+    override fun onBindViewHolder(holder: ViewHolder, position: Int) {
         holder.bind(getItem(position))
     }
+
+    // Generic ViewHolder for a detail album
+    inner class ViewHolder(
+        private val binding: ItemQueueSongBinding,
+    ) : BaseViewHolder<Song>(binding, null) {
+
+        @SuppressLint("ClickableViewAccessibility")
+        override fun onBind(model: Song) {
+            binding.song = model
+            binding.songDragHandle.setOnTouchListener { _, motionEvent ->
+                binding.songDragHandle.performClick()
+
+                if (motionEvent.actionMasked == MotionEvent.ACTION_DOWN) {
+                    dragCallback.startDrag(this)
+                    return@setOnTouchListener true
+                }
+
+                false
+            }
+
+            binding.songName.requestLayout()
+            binding.songInfo.requestLayout()
+        }
+    }
 }

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

@@ -0,0 +1,55 @@
+package org.oxycblt.auxio.playback.queue
+
+import androidx.recyclerview.widget.ItemTouchHelper
+import androidx.recyclerview.widget.RecyclerView
+import org.oxycblt.auxio.playback.PlaybackViewModel
+import kotlin.math.abs
+import kotlin.math.min
+import kotlin.math.sign
+
+class QueueDragCallback(private val playbackModel: PlaybackViewModel) :
+    ItemTouchHelper.SimpleCallback(
+        ItemTouchHelper.UP or ItemTouchHelper.DOWN,
+        ItemTouchHelper.START
+    ) {
+    override fun interpolateOutOfBoundsScroll(
+        recyclerView: RecyclerView,
+        viewSize: Int,
+        viewSizeOutOfBounds: Int,
+        totalSize: Int,
+        msSinceStartScroll: Long
+    ): Int {
+        val standardSpeed = super.interpolateOutOfBoundsScroll(
+            recyclerView, viewSize, viewSizeOutOfBounds, totalSize, msSinceStartScroll
+        )
+
+        val clampedAbsVelocity = Math.max(
+            MINIMUM_INITIAL_DRAG_VELOCITY,
+            min(
+                abs(standardSpeed),
+                MAXIMUM_INITIAL_DRAG_VELOCITY
+            )
+        )
+
+        return clampedAbsVelocity * sign(viewSizeOutOfBounds.toDouble()).toInt()
+    }
+
+    override fun onMove(
+        recyclerView: RecyclerView,
+        viewHolder: RecyclerView.ViewHolder,
+        target: RecyclerView.ViewHolder
+    ): Boolean {
+        playbackModel.moveQueueItems(viewHolder.adapterPosition, target.adapterPosition)
+
+        return true
+    }
+
+    override fun onSwiped(viewHolder: RecyclerView.ViewHolder, direction: Int) {
+        playbackModel.removeQueueItem(viewHolder.adapterPosition)
+    }
+
+    companion object {
+        const val MINIMUM_INITIAL_DRAG_VELOCITY = 10
+        const val MAXIMUM_INITIAL_DRAG_VELOCITY = 25
+    }
+}

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

@@ -5,6 +5,8 @@ import android.view.LayoutInflater
 import android.view.View
 import android.view.ViewGroup
 import androidx.fragment.app.activityViewModels
+import androidx.recyclerview.widget.DefaultItemAnimator
+import androidx.recyclerview.widget.ItemTouchHelper
 import com.google.android.material.bottomsheet.BottomSheetDialogFragment
 import org.oxycblt.auxio.R
 import org.oxycblt.auxio.databinding.FragmentQueueBinding
@@ -25,7 +27,9 @@ class QueueFragment : BottomSheetDialogFragment() {
     ): View? {
         val binding = FragmentQueueBinding.inflate(inflater)
 
-        val queueAdapter = QueueAdapter {}
+        val helper = ItemTouchHelper(QueueDragCallback(playbackModel))
+
+        val queueAdapter = QueueAdapter(helper)
 
         // --- UI SETUP ---
 
@@ -34,12 +38,15 @@ class QueueFragment : BottomSheetDialogFragment() {
             adapter = queueAdapter
             applyDivider()
             setHasFixedSize(true)
+            itemAnimator = DefaultItemAnimator()
+
+            helper.attachToRecyclerView(this)
         }
 
         // --- VIEWMODEL SETUP ---
 
         playbackModel.formattedQueue.observe(viewLifecycleOwner) {
-            queueAdapter.submitList(it)
+            queueAdapter.submitList(it.toMutableList())
         }
 
         return binding.root

app/src/main/res/drawable/ic_handle.xml

@@ -0,0 +1,11 @@
+<?xml version="1.0" encoding="utf-8"?>
+<vector xmlns:android="http://schemas.android.com/apk/res/android"
+    android:width="24dp"
+    android:height="24dp"
+    android:viewportWidth="24"
+    android:viewportHeight="24"
+    android:tint="?android:attr/colorControlNormal">
+    <path
+        android:fillColor="@android:color/white"
+        android:pathData="M20,9H4v2h16V9zM4,15h16v-2H4V15z" />
+</vector>

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

@@ -0,0 +1,79 @@
+<?xml version="1.0" encoding="utf-8"?>
+<layout xmlns:app="http://schemas.android.com/apk/res-auto"
+    xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:tools="http://schemas.android.com/tools"
+    tools:context=".recycler.viewholders.SongViewHolder">
+
+    <data>
+
+        <variable
+            name="song"
+            type="org.oxycblt.auxio.music.Song" />
+    </data>
+
+    <androidx.constraintlayout.widget.ConstraintLayout
+        android:layout_width="match_parent"
+        android:layout_height="wrap_content"
+        android:padding="@dimen/padding_medium">
+
+        <ImageView
+            android:id="@+id/album_cover"
+            android:layout_width="@dimen/size_cover_compact"
+            android:layout_height="@dimen/size_cover_compact"
+            android:contentDescription="@{@string/description_album_cover(song.name)}"
+            app:coverArt="@{song}"
+            app:layout_constraintBottom_toBottomOf="parent"
+            app:layout_constraintStart_toStartOf="parent"
+            app:layout_constraintTop_toTopOf="parent"
+            tools:ignore="ContentDescription"
+            tools:src="@drawable/ic_song" />
+
+        <TextView
+            android:id="@+id/song_name"
+            android:layout_width="0dp"
+            android:layout_height="wrap_content"
+            android:layout_marginStart="@dimen/margin_medium"
+            android:layout_marginEnd="@dimen/margin_medium"
+            android:ellipsize="end"
+            android:maxLines="1"
+            android:text="@{song.name}"
+            android:textAppearance="?android:attr/textAppearanceListItem"
+            android:textColor="?android:attr/textColorPrimary"
+            app:layout_constraintBottom_toTopOf="@+id/song_info"
+            app:layout_constraintEnd_toStartOf="@+id/song_drag_handle"
+            app:layout_constraintStart_toEndOf="@+id/album_cover"
+            app:layout_constraintTop_toTopOf="parent"
+            app:layout_constraintVertical_chainStyle="packed"
+            tools:text="Song Name" />
+
+        <TextView
+            android:id="@+id/song_info"
+            android:layout_width="0dp"
+            android:layout_height="wrap_content"
+            android:layout_marginStart="@dimen/margin_medium"
+            android:layout_marginEnd="@dimen/margin_medium"
+            android:ellipsize="end"
+            android:maxLines="1"
+            android:textAppearance="?android:attr/textAppearanceListItemSecondary"
+            android:textColor="?android:attr/textColorSecondary"
+            android:text="@{@string/format_info(song.album.artist.name, song.album.name)}"
+            app:layout_constraintBottom_toBottomOf="parent"
+            app:layout_constraintEnd_toStartOf="@+id/song_drag_handle"
+            app:layout_constraintStart_toEndOf="@+id/album_cover"
+            app:layout_constraintTop_toBottomOf="@+id/song_name"
+            tools:text="Artist / Album" />
+
+        <ImageView
+            android:id="@+id/song_drag_handle"
+            android:layout_width="wrap_content"
+            android:layout_height="wrap_content"
+            android:src="@drawable/ic_handle"
+            android:clickable="true"
+            android:focusable="true"
+            app:layout_constraintBottom_toBottomOf="parent"
+            app:layout_constraintEnd_toEndOf="parent"
+            app:layout_constraintTop_toTopOf="parent"
+            tools:ignore="ContentDescription" />
+
+    </androidx.constraintlayout.widget.ConstraintLayout>
+</layout>

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

@@ -10,17 +10,18 @@
         <item name="android:fitsSystemWindows">true</item>
     </style>
 
-    <!-- Toolbar Themes -->
+    <!-- Hack to fix the weird icon/underline with LibraryFragment's SearchView -->
     <style name="Toolbar.Style" parent="ThemeOverlay.MaterialComponents.ActionBar">
         <item name="android:searchViewStyle">@style/Widget.AppCompat.SearchView</item>
     </style>
 
+    <!-- Toolbar Title Theme -->
     <style name="TextAppearance.Toolbar.Header" parent="TextAppearance.Widget.AppCompat.Toolbar.Title">
         <item name="android:fontFamily">@font/inter_black</item>
         <item name="android:textColor">?android:attr/colorPrimary</item>
     </style>
 
-    <!-- Header Themes -->
+    <!-- Title theme for Detail Fragments -->
     <style name="DetailHeader">
         <item name="android:textAppearance">?android:attr/textAppearanceLarge</item>
         <item name="android:textColor">?android:attr/colorPrimary</item>
@@ -28,6 +29,7 @@
         <item name="android:textSize">@dimen/text_size_header_max</item>
     </style>
 
+    <!-- Smaller Title theme that is used for headers -->
     <style name="TextAppearance.SmallHeader" parent="TextAppearance.MaterialComponents.Body2">
         <item name="android:fontFamily">@font/inter_semibold</item>
     </style>