all: minor cleanup

Do some minor cleanup before the next release.

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

@@ -30,8 +30,11 @@ import org.oxycblt.auxio.coil.MusicKeyer
 import org.oxycblt.auxio.settings.SettingsManager
 
 /**
- * TODO: Phase out databinding
- * TODO: Rework sealed classes to minimize whens and maximize overrides
+ * TODO: Plan for a general UI rework
+ *       - Refactor fragment class
+ *       - Remove databinding and dedup layouts
+ *       - Rework RecyclerView management and item dragging
+ *       - Rework sealed classes to minimize whens and maximize overrides
  */
 @Suppress("UNUSED")
 class AuxioApp : Application(), ImageLoaderFactory {

app/src/main/java/org/oxycblt/auxio/music/MusicLoader.kt

@@ -130,6 +130,8 @@ class MusicLoader {
             args += "$path%" // Append % so that the selector properly detects children
         }
 
+        // TODO: Move all references to contentResolver into a single variable so we can
+        //  avoid accidentally removing the applicationContext fix
         context.applicationContext.contentResolver.query(
             MediaStore.Audio.Media.EXTERNAL_CONTENT_URI,
             arrayOf(
@@ -142,7 +144,7 @@ class MusicLoader {
                 MediaStore.Audio.AudioColumns.ALBUM,
                 MediaStore.Audio.AudioColumns.ALBUM_ID,
                 MediaStore.Audio.AudioColumns.ARTIST,
-                MediaStore.Audio.AudioColumns.ALBUM_ARTIST,
+                AUDIO_COLUMN_ALBUM_ARTIST
             ),
             selector, args.toTypedArray(), null
         )?.use { cursor ->
@@ -155,7 +157,7 @@ class MusicLoader {
             val albumIndex = cursor.getColumnIndexOrThrow(MediaStore.Audio.AudioColumns.ALBUM)
             val albumIdIndex = cursor.getColumnIndexOrThrow(MediaStore.Audio.AudioColumns.ALBUM_ID)
             val artistIndex = cursor.getColumnIndexOrThrow(MediaStore.Audio.AudioColumns.ARTIST)
-            val albumArtistIndex = cursor.getColumnIndexOrThrow(MediaStore.Audio.AudioColumns.ALBUM_ARTIST)
+            val albumArtistIndex = cursor.getColumnIndexOrThrow(AUDIO_COLUMN_ALBUM_ARTIST)
 
             while (cursor.moveToNext()) {
                 val id = cursor.getLong(idIndex)
@@ -412,6 +414,15 @@ class MusicLoader {
     }
 
     companion object {
+        /**
+         * The album_artist MediaStore field has existed since at least API 21, but until API
+         * 30 it was a proprietary extension for Google Play Music and was not documented.
+         * Since this field probably works on all versions Auxio supports, we suppress the
+         * warning about using a possibly-unsupported constant.
+         */
+        @Suppress("InlinedApi")
+        const val AUDIO_COLUMN_ALBUM_ARTIST = MediaStore.Audio.AudioColumns.ALBUM_ARTIST
+
         /**
          * A complete array of all the hardcoded genre values for ID3(v2), contains standard genres and
          * winamp extensions.

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

@@ -21,7 +21,7 @@ import org.oxycblt.auxio.util.getDrawableSafe
  *
  * This view also enables use of an "indicator", which is a dot that can denote when a
  * button is active. This is useful for the shuffle/loop buttons, as at times highlighting
- * them is not enough to
+ * them is not enough to differentiate them.
  */
 class PlaybackButton @JvmOverloads constructor(
     context: Context,
@@ -73,6 +73,7 @@ class PlaybackButton @JvmOverloads constructor(
             }
         }
 
+        // Put the indicator right below the icon.
         val x = (measuredWidth - indicatorDrawable.intrinsicWidth) / 2
         val y = ((measuredHeight - iconSize) / 2) + iconSize
 
@@ -81,9 +82,11 @@ class PlaybackButton @JvmOverloads constructor(
         )
     }
 
-    override fun onDrawForeground(canvas: Canvas) {
-        super.onDrawForeground(canvas)
+    override fun onDraw(canvas: Canvas) {
+        super.onDraw(canvas)
 
+        // I would use onDrawForeground but apparently that isn't called by Lollipop devices.
+        // This is not referenced in the documentation at all.
         if (hasIndicator && isActivated) {
             indicatorDrawable.draw(canvas)
         }