list: add update instructions framework

Add the basic framework that should allow for different types of list
updates in different situations.

CHANGELOG.md

@@ -2,6 +2,9 @@
 
 ## dev
 
+#### What's New
+- Added ability to play/shuffle selections
+
 #### What's Improved
 - Added ability to edit previously played or currently playing items in the queue
 - Added support for date values formatted as "YYYYMMDD"

app/src/main/java/org/oxycblt/auxio/MainFragment.kt

@@ -343,10 +343,8 @@ class MainFragment :
         if (playbackSheetBehavior.state == NeoBottomSheetBehavior.STATE_HIDDEN) {
             val queueSheetBehavior =
                 binding.queueSheet.coordinatorLayoutBehavior as QueueBottomSheetBehavior?
-
             // Queue sheet behavior is either collapsed or expanded, no hiding needed
             queueSheetBehavior?.isDraggable = true
-
             playbackSheetBehavior.apply {
                 // Make sure the view is draggable, at least until the draw checks kick in.
                 isDraggable = true

app/src/main/java/org/oxycblt/auxio/list/UpdateInstructions.kt

@@ -0,0 +1,19 @@
+package org.oxycblt.auxio.list
+
+/**
+ * Represents the specific way to update a list of items.
+ * @author Alexander Capehart (OxygenCobalt)
+ */
+enum class UpdateInstructions {
+    /**
+     * (A)synchronously diff the list. This should be used for small diffs with little item
+     * movement.
+     */
+    DIFF,
+
+    /**
+     * Synchronously remove the current list and replace it with a new one. This should be used
+     * for large diffs with that would cause erratic scroll behavior or in-efficiency.
+     */
+    REPLACE
+}

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

@@ -242,7 +242,7 @@ class PlaybackViewModel(application: Application) :
      * @param selection The selection to play.
      */
     fun play(selection: List<Music>) =
-        playbackManager.play(null, selectionToSongs(selection), false)
+        playbackManager.play(null, null, selectionToSongs(selection), false)
 
     /**
      * Shuffle an [Album].
@@ -267,7 +267,7 @@ class PlaybackViewModel(application: Application) :
      * @param selection The selection to shuffle.
      */
     fun shuffle(selection: List<Music>) =
-        playbackManager.play(null, selectionToSongs(selection), true)
+        playbackManager.play(null, null, selectionToSongs(selection), true)
 
     private fun playImpl(
         song: Song?,
@@ -286,7 +286,7 @@ class PlaybackViewModel(application: Application) :
                 null -> musicSettings.songSort
             }
         val queue = sort.songs(parent?.songs ?: library.songs)
-        playbackManager.play(song, queue, shuffled)
+        playbackManager.play(song, parent, queue, shuffled)
     }
 
     /**

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

@@ -27,6 +27,7 @@ import androidx.recyclerview.widget.RecyclerView
 import kotlin.math.min
 import org.oxycblt.auxio.databinding.FragmentQueueBinding
 import org.oxycblt.auxio.list.EditableListListener
+import org.oxycblt.auxio.list.UpdateInstructions
 import org.oxycblt.auxio.music.Song
 import org.oxycblt.auxio.playback.PlaybackViewModel
 import org.oxycblt.auxio.ui.ViewBindingFragment
@@ -100,18 +101,19 @@ class QueueFragment : ViewBindingFragment<FragmentQueueBinding>(), EditableListL
         val binding = requireBinding()
 
         // Replace or diff the queue depending on the type of change it is.
-        // TODO: Extend this to the whole app.
-        if (queueModel.replaceQueue == true) {
+        val instructions = queueModel.instructions
+        if (instructions?.update == UpdateInstructions.REPLACE) {
             logD("Replacing queue")
             queueAdapter.replaceList(queue)
         } else {
             logD("Diffing queue")
             queueAdapter.submitList(queue)
         }
-        queueModel.finishReplace()
+        // Update position in list (and thus past/future items)
+        queueAdapter.setPosition(index, isPlaying)
 
         // If requested, scroll to a new item (occurs when the index moves)
-        val scrollTo = queueModel.scrollTo
+        val scrollTo = instructions?.scrollTo
         if (scrollTo != null) {
             val lmm = binding.queueRecycler.layoutManager as LinearLayoutManager
             val start = lmm.findFirstCompletelyVisibleItemPosition()
@@ -132,9 +134,7 @@ class QueueFragment : ViewBindingFragment<FragmentQueueBinding>(), EditableListL
                     min(queue.lastIndex, scrollTo + (end - start)))
             }
         }
-        queueModel.finishScrollTo()
 
-        // Update position in list (and thus past/future items)
-        queueAdapter.setPosition(index, isPlaying)
+        queueModel.finishInstructions()
     }
 }

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

@@ -20,6 +20,7 @@ package org.oxycblt.auxio.playback.queue
 import androidx.lifecycle.ViewModel
 import kotlinx.coroutines.flow.MutableStateFlow
 import kotlinx.coroutines.flow.StateFlow
+import org.oxycblt.auxio.list.UpdateInstructions
 import org.oxycblt.auxio.music.MusicParent
 import org.oxycblt.auxio.music.Song
 import org.oxycblt.auxio.playback.state.PlaybackStateManager
@@ -42,15 +43,47 @@ class QueueViewModel : ViewModel(), PlaybackStateManager.Listener {
     val index: StateFlow<Int>
         get() = _index
 
-    /** Whether to replace or diff the queue list when updating it. Is null if not specified. */
-    var replaceQueue: Boolean? = null
-    /** Flag to scroll to a particular queue item. Is null if no command has been specified. */
-    var scrollTo: Int? = null
+    /** Specifies how to update the list when the queue changes. */
+    var instructions: Instructions? = null
 
     init {
         playbackManager.addListener(this)
     }
 
+    override fun onIndexMoved(queue: Queue) {
+        instructions = Instructions(null, queue.index)
+        _index.value = queue.index
+    }
+
+    override fun onQueueChanged(queue: Queue, change: Queue.ChangeResult) {
+        // Queue changed trivially due to item mo -> Diff queue, stay at current index.
+        instructions = Instructions(UpdateInstructions.DIFF, null)
+        _queue.value = queue.resolve()
+        if (change != Queue.ChangeResult.MAPPING) {
+            // Index changed, make sure it remains updated without actually scrolling to it.
+            _index.value = queue.index
+        }
+    }
+
+    override fun onQueueReordered(queue: Queue) {
+        // Queue changed completely -> Replace queue, update index
+        instructions = Instructions(UpdateInstructions.REPLACE, null)
+        _queue.value = queue.resolve()
+        _index.value = queue.index
+    }
+
+    override fun onNewPlayback(queue: Queue, parent: MusicParent?) {
+        // Entirely new queue -> Replace queue, update index
+        instructions = Instructions(UpdateInstructions.REPLACE, null)
+        _queue.value = queue.resolve()
+        _index.value = queue.index
+    }
+
+    override fun onCleared() {
+        super.onCleared()
+        playbackManager.removeListener(this)
+    }
+
     /**
      * Start playing the the queue item at the given index.
      * @param adapterIndex The index of the queue item to play. Does nothing if the index is out of
@@ -86,52 +119,10 @@ class QueueViewModel : ViewModel(), PlaybackStateManager.Listener {
         return true
     }
 
-    /** Finish a replace flag specified by [replaceQueue]. */
-    fun finishReplace() {
-        replaceQueue = null
+    /** Signal that the specified [Instructions] in [instructions] were performed. */
+    fun finishInstructions() {
+        instructions = null
     }
 
-    /** Finish a scroll operation started by [scrollTo]. */
-    fun finishScrollTo() {
-        scrollTo = null
-    }
-
-    override fun onIndexMoved(queue: Queue) {
-        // Index moved -> Scroll to new index
-        replaceQueue = null
-        scrollTo = queue.index
-        _index.value = queue.index
-    }
-
-    override fun onQueueChanged(queue: Queue, change: Queue.ChangeResult) {
-        // Queue changed trivially due to item mo -> Diff queue, stay at current index.
-        replaceQueue = false
-        scrollTo = null
-        _queue.value = queue.resolve()
-        if (change != Queue.ChangeResult.MAPPING) {
-            // Index changed, make sure it remains updated without actually scrolling to it.
-            _index.value = queue.index
-        }
-    }
-
-    override fun onQueueReordered(queue: Queue) {
-        // Queue changed completely -> Replace queue, update index
-        replaceQueue = true
-        scrollTo = queue.index
-        _queue.value = queue.resolve()
-        _index.value = queue.index
-    }
-
-    override fun onNewPlayback(queue: Queue, parent: MusicParent?) {
-        // Entirely new queue -> Replace queue, update index
-        replaceQueue = true
-        scrollTo = queue.index
-        _queue.value = queue.resolve()
-        _index.value = queue.index
-    }
-
-    override fun onCleared() {
-        super.onCleared()
-        playbackManager.removeListener(this)
-    }
+    class Instructions(val update: UpdateInstructions?, val scrollTo: Int?)
 }

app/src/main/java/org/oxycblt/auxio/playback/state/PlaybackStateManager.kt

@@ -23,7 +23,6 @@ import org.oxycblt.auxio.BuildConfig
 import org.oxycblt.auxio.music.*
 import org.oxycblt.auxio.music.MusicStore
 import org.oxycblt.auxio.music.library.Library
-import org.oxycblt.auxio.music.library.Sort
 import org.oxycblt.auxio.playback.state.PlaybackStateManager.Listener
 import org.oxycblt.auxio.util.logD
 import org.oxycblt.auxio.util.logE
@@ -60,7 +59,7 @@ class PlaybackStateManager private constructor() {
     val queue = Queue()
     /** The [MusicParent] currently being played. Null if playback is occurring from all songs. */
     @Volatile
-    var parent: MusicParent? = null
+    var parent: MusicParent? = null // TODO: Parent is interpreted wrong when nothing is playing.
         private set
 
     /** The current [InternalPlayer] state. */
@@ -98,7 +97,7 @@ class PlaybackStateManager private constructor() {
     }
 
     /**
-     * Remove a [Listener] from this instance, preventing it from recieving any further updates.
+     * Remove a [Listener] from this instance, preventing it from receiving any further updates.
      * @param listener The [Listener] to remove. Does nothing if the [Listener] was never added in
      * the first place.
      * @see Listener
@@ -156,14 +155,13 @@ class PlaybackStateManager private constructor() {
      * Start new playback.
      * @param song A particular [Song] to play, or null to play the first [Song] in the new queue.
      * @param queue The queue of [Song]s to play from.
-     * @param parent The [MusicParent] to play from, or null if to play from the entire [Library].
-     * @param sort [Sort] to initially sort an ordered queue with.
+     * @param parent The [MusicParent] to play from, or null if to play from an non-specific
+     * collection of "All [Song]s".
      * @param shuffled Whether to shuffle or not.
      */
     @Synchronized
-    fun play(song: Song?, queue: List<Song>, shuffled: Boolean) {
+    fun play(song: Song?, parent: MusicParent?, queue: List<Song>, shuffled: Boolean) {
         val internalPlayer = internalPlayer ?: return
-        val library = musicStore.library ?: return
         // Set up parent and queue
         this.parent = parent
         this.queue.start(song, queue, shuffled)

app/src/main/java/org/oxycblt/auxio/playback/state/Queue.kt

@@ -208,8 +208,9 @@ class Queue {
             // We have moved an song from in front of the playing song to behind, shift forward.
             in dst until src -> index += 1
             else -> {
+                // Nothing to do.
                 check()
-                ChangeResult.MAPPING
+                return ChangeResult.MAPPING
             }
         }
         check()

app/src/main/java/org/oxycblt/auxio/playback/system/PlaybackService.kt

@@ -355,13 +355,14 @@ class PlaybackService :
             }
             // Shuffle all -> Start new playback from all songs
             is InternalPlayer.Action.ShuffleAll -> {
-                playbackManager.play(null, musicSettings.songSort.songs(library.songs), true)
+                playbackManager.play(null, null, musicSettings.songSort.songs(library.songs), true)
             }
             // Open -> Try to find the Song for the given file and then play it from all songs
             is InternalPlayer.Action.Open -> {
                 library.findSongForUri(application, action.uri)?.let { song ->
                     playbackManager.play(
                         song,
+                        null,
                         musicSettings.songSort.songs(library.songs),
                         playbackManager.queue.isShuffled && playbackSettings.keepShuffle)
                 }

app/src/main/java/org/oxycblt/auxio/settings/AboutFragment.kt

@@ -123,8 +123,7 @@ class AboutFragment : ViewBindingFragment<FragmentAboutBinding>() {
                 if (pkgName == "android") {
                     // No default browser [Must open app chooser, may not be supported]
                     openAppChooser(browserIntent)
-                } else {
-                    try {
+                } else try {
                     browserIntent.setPackage(pkgName)
                     startActivity(browserIntent)
                 } catch (e: ActivityNotFoundException) {
@@ -132,7 +131,6 @@ class AboutFragment : ViewBindingFragment<FragmentAboutBinding>() {
                     browserIntent.setPackage(null)
                     openAppChooser(browserIntent)
                 }
-                }
             } else {
                 // No app installed to open the link
                 context.showToast(R.string.err_no_app)

app/src/main/java/org/oxycblt/auxio/settings/Settings.kt

@@ -88,6 +88,11 @@ interface Settings<L> {
             onSettingChanged(key, unlikelyToBeNull(listener))
         }
 
-        open fun onSettingChanged(key: String, listener: L) {}
+        /**
+         * Called when a setting entry with the given [key] has changed.
+         * @param key The key of the changed setting.
+         * @param listener The implementation's listener that updates should be applied to.
+         */
+        protected open fun onSettingChanged(key: String, listener: L) {}
     }
 }

app/src/main/java/org/oxycblt/auxio/ui/BaseBottomSheetBehavior.kt

@@ -56,7 +56,7 @@ abstract class BaseBottomSheetBehavior<V : View>(context: Context, attributeSet:
     /**
      * Called when window insets are being applied to the [View] this [BaseBottomSheetBehavior] is
      * linked to.
-     * @param child The child view recieving the [WindowInsets].
+     * @param child The child view receiving the [WindowInsets].
      * @param insets The [WindowInsets] to apply.
      * @return The (possibly modified) [WindowInsets].
      * @see View.onApplyWindowInsets

app/src/main/java/org/oxycblt/auxio/ui/ViewBindingDialogFragment.kt

@@ -74,12 +74,11 @@ abstract class ViewBindingDialogFragment<VB : ViewBinding> : DialogFragment() {
      * @return The currently-inflated [ViewBinding].
      * @throws IllegalStateException if the [ViewBinding] is not inflated.
      */
-    protected fun requireBinding(): VB {
-        return requireNotNull(_binding) {
+    protected fun requireBinding() =
+        requireNotNull(_binding) {
             "ViewBinding was available. Fragment should be a valid state " +
                 "right now, but instead it was ${lifecycle.currentState}"
         }
-    }
 
     final override fun onCreateView(
         inflater: LayoutInflater,

app/src/main/java/org/oxycblt/auxio/ui/ViewBindingFragment.kt

@@ -65,12 +65,11 @@ abstract class ViewBindingFragment<VB : ViewBinding> : Fragment() {
      * @return The currently-inflated [ViewBinding].
      * @throws IllegalStateException if the [ViewBinding] is not inflated.
      */
-    protected fun requireBinding(): VB {
-        return requireNotNull(_binding) {
+    protected fun requireBinding() =
+        requireNotNull(_binding) {
             "ViewBinding was available. Fragment should be a valid state " +
                 "right now, but instead it was ${lifecycle.currentState}"
         }
-    }
 
     final override fun onCreateView(
         inflater: LayoutInflater,