recycler: fix popup desync in grid layouts [#230]

Fix a popup desynchronization issue in grid-based layouts.

This issue stemmed from the popup index calculation apparently not
needing a division by the span count in order to produce the correct
index. This kind of makes sense, but is still really weird.

Resolves #230.

CHANGELOG.md

@@ -2,6 +2,9 @@
 
 ## dev
 
+#### What's Fixed
+- Fixed issue wher the scroll popup would not display correctly in landscape mode [#230]
+
 ## 2.6.3
 
 #### What's New

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

@@ -79,10 +79,11 @@ class ArtistListFragment : HomeListFragment<Artist>() {
     }
 
     override fun onOpenMenu(item: Item, anchor: View) {
-        when (item) {
+        if (item is Artist) {
-            is Artist -> musicMenu(anchor, R.menu.menu_genre_artist_actions, item)
+            musicMenu(anchor, R.menu.menu_genre_artist_actions, item)
-            else -> error("Unexpected datatype when opening menu: ${item::class.java}")
         }
+
+        error("Unexpected datatype when opening menu: ${item::class.java}")
     }
 
     private fun handleParent(parent: MusicParent?, isPlaying: Boolean) {

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

@@ -163,7 +163,9 @@ class PlaybackStateManager private constructor() {
                 PlaybackMode.IN_ALBUM -> song.album
                 PlaybackMode.IN_ARTIST -> song.album.artist
                 PlaybackMode.IN_GENRE ->
-                    song.genres.maxBy { it.songs.size } // TODO: Stopgap measure until I can rework this and add selection
+                    song.genres.maxBy {
+                        it.songs.size
+                    } // TODO: Stopgap measure until I can rework this and add selection
             }
 
         applyNewQueue(library, settings, settings.keepShuffle && isShuffled, song)

app/src/main/java/org/oxycblt/auxio/ui/fastscroll/FastScrollRecyclerView.kt

@@ -208,13 +208,20 @@ constructor(context: Context, attrs: AttributeSet? = null, @AttrRes defStyleAttr
 
         thumbView.layout(thumbLeft, thumbTop, thumbLeft + thumbWidth, thumbTop + thumbHeight)
 
-        val firstPos = firstAdapterPos
+        val child = getChildAt(0)
+        val firstAdapterPos =
+            if (child != null) {
+                layoutManager?.getPosition(child) ?: NO_POSITION
+            } else {
+                NO_POSITION
+            }
+
         val popupText: String
         val provider = popupProvider
-        if (firstPos != NO_POSITION && provider != null) {
+        if (firstAdapterPos != NO_POSITION && provider != null) {
             popupView.isInvisible = false
             // Get the popup text. If there is none, we default to "?".
-            popupText = provider.getPopup(firstPos) ?: "?"
+            popupText = provider.getPopup(firstAdapterPos) ?: "?"
         } else {
             // No valid position or provider, do not show the popup.
             popupView.isInvisible = true
@@ -298,6 +305,14 @@ constructor(context: Context, attrs: AttributeSet? = null, @AttrRes defStyleAttr
         // Combine the previous item dimensions with the current item top to find our scroll
         // position
         getDecoratedBoundsWithMargins(getChildAt(0), tRect)
+        val child = getChildAt(0)
+        val firstAdapterPos =
+            when (val mgr = layoutManager) {
+                is GridLayoutManager -> mgr.getPosition(child) / mgr.spanCount
+                is LinearLayoutManager -> mgr.getPosition(child)
+                else -> 0
+            }
+
         val scrollOffset = paddingTop + (firstAdapterPos * itemHeight) - tRect.top
 
         // Then calculate the thumb position, which is just:
@@ -474,21 +489,6 @@ constructor(context: Context, attrs: AttributeSet? = null, @AttrRes defStyleAttr
     private val scrollOffsetRange: Int
         get() = scrollRange - height
 
-    private val firstAdapterPos: Int
-        get() {
-            if (childCount == 0) {
-                return NO_POSITION
-            }
-
-            val child = getChildAt(0)
-
-            return when (val mgr = layoutManager) {
-                is GridLayoutManager -> mgr.getPosition(child) / mgr.spanCount
-                is LinearLayoutManager -> mgr.getPosition(child)
-                else -> 0
-            }
-        }
-
     private val itemHeight: Int
         get() {
             if (childCount == 0) {