fix some recycler glitches at the directories view

app/build.gradle

@@ -47,7 +47,7 @@ ext {
 }
 
 dependencies {
-    implementation 'com.simplemobiletools:commons:4.3.1'
+    implementation 'com.simplemobiletools:commons:4.3.2'
     implementation 'com.theartofdev.edmodo:android-image-cropper:2.7.0'
     implementation 'com.android.support:multidex:1.0.3'
     implementation 'it.sephiroth.android.exif:library:1.0.1'

app/src/main/kotlin/com/simplemobiletools/gallery/activities/MainActivity.kt

@@ -425,6 +425,32 @@ class MainActivity : SimpleActivity(), DirectoryAdapter.DirOperationsListener {
         layoutManager.spanCount = config.dirColumnCnt
     }
 
+    private fun measureRecyclerViewContent(directories: ArrayList<Directory>) {
+        directories_grid.onGlobalLayout {
+            if (config.scrollHorizontally) {
+                calculateContentWidth(directories)
+            } else {
+                calculateContentHeight(directories)
+            }
+        }
+    }
+
+    private fun calculateContentWidth(directories: ArrayList<Directory>) {
+        val layoutManager = directories_grid.layoutManager as MyGridLayoutManager
+        val thumbnailWidth = layoutManager.getChildAt(0)?.width ?: 0
+        val fullWidth = ((directories.size - 1) / layoutManager.spanCount + 1) * thumbnailWidth
+        directories_horizontal_fastscroller.setContentWidth(fullWidth)
+        directories_horizontal_fastscroller.setScrollToX(directories_grid.computeHorizontalScrollOffset())
+    }
+
+    private fun calculateContentHeight(directories: ArrayList<Directory>) {
+        val layoutManager = directories_grid.layoutManager as MyGridLayoutManager
+        val thumbnailHeight = layoutManager.getChildAt(0)?.height ?: 0
+        val fullHeight = ((directories.size - 1) / layoutManager.spanCount + 1) * thumbnailHeight
+        directories_vertical_fastscroller.setContentHeight(fullHeight)
+        directories_vertical_fastscroller.setScrollToY(directories_grid.computeVerticalScrollOffset())
+    }
+
     private fun initZoomListener() {
         if (config.viewTypeFolders == VIEW_TYPE_GRID) {
             val layoutManager = directories_grid.layoutManager as MyGridLayoutManager
@@ -466,19 +492,19 @@ class MainActivity : SimpleActivity(), DirectoryAdapter.DirOperationsListener {
     }
 
     private fun increaseColumnCount() {
-        directories_vertical_fastscroller.measureRecyclerViewOnRedraw()
-        directories_horizontal_fastscroller.measureRecyclerViewOnRedraw()
         config.dirColumnCnt = ++(directories_grid.layoutManager as MyGridLayoutManager).spanCount
-        invalidateOptionsMenu()
-        directories_grid.adapter?.notifyDataSetChanged()
+        columnCountChanged()
     }
 
     private fun reduceColumnCount() {
-        directories_vertical_fastscroller.measureRecyclerViewOnRedraw()
-        directories_horizontal_fastscroller.measureRecyclerViewOnRedraw()
         config.dirColumnCnt = --(directories_grid.layoutManager as MyGridLayoutManager).spanCount
+        columnCountChanged()
+    }
+
+    private fun columnCountChanged() {
         invalidateOptionsMenu()
         directories_grid.adapter?.notifyDataSetChanged()
+        measureRecyclerViewContent(getRecyclerAdapter()!!.dirs)
     }
 
     private fun isPickImageIntent(intent: Intent) = isPickIntent(intent) && (hasImageContentData(intent) || isImageType(intent))
@@ -698,7 +724,6 @@ class MainActivity : SimpleActivity(), DirectoryAdapter.DirOperationsListener {
 
             runOnUiThread {
                 directories_refresh_layout.isRefreshing = false
-                directories_vertical_fastscroller.measureRecyclerView()
                 checkPlaceholderVisibility(dirs)
             }
             checkInvalidDirectories(dirs, directoryDao)
@@ -763,12 +788,14 @@ class MainActivity : SimpleActivity(), DirectoryAdapter.DirOperationsListener {
             (currAdapter as DirectoryAdapter).updateDirs(directories)
         }
 
+        getRecyclerAdapter()?.dirs?.apply {
+            measureRecyclerViewContent(this)
+        }
         setupScrollDirection()
     }
 
     private fun setupScrollDirection() {
         val allowHorizontalScroll = config.scrollHorizontally && config.viewTypeFolders == VIEW_TYPE_GRID
-
         directories_vertical_fastscroller.isHorizontal = false
         directories_vertical_fastscroller.beGoneIf(allowHorizontalScroll)
 

app/src/main/kotlin/com/simplemobiletools/gallery/activities/MediaActivity.kt

@@ -355,7 +355,6 @@ class MediaActivity : SimpleActivity(), MediaAdapter.MediaOperationsListener {
         media_horizontal_fastscroller.beVisibleIf(allowHorizontalScroll)
 
         val sorting = config.getFileSorting(mPath)
-
         if (allowHorizontalScroll) {
             media_horizontal_fastscroller.allowBubbleDisplay = config.showInfoBubble
             media_horizontal_fastscroller.setViews(media_grid, media_refresh_layout) {
@@ -603,8 +602,8 @@ class MediaActivity : SimpleActivity(), MediaAdapter.MediaOperationsListener {
 
     private fun calculateContentWidth(media: ArrayList<ThumbnailItem>) {
         val layoutManager = media_grid.layoutManager as MyGridLayoutManager
-        val mThumbnailWidth = layoutManager.getChildAt(0)?.width ?: 0
-        val fullWidth = ((media.size - 1) / layoutManager.spanCount + 1) * mThumbnailWidth
+        val thumbnailWidth = layoutManager.getChildAt(0)?.width ?: 0
+        val fullWidth = ((media.size - 1) / layoutManager.spanCount + 1) * thumbnailWidth
         media_horizontal_fastscroller.setContentWidth(fullWidth)
         media_horizontal_fastscroller.setScrollToX(media_grid.computeHorizontalScrollOffset())
     }
@@ -612,18 +611,18 @@ class MediaActivity : SimpleActivity(), MediaAdapter.MediaOperationsListener {
     private fun calculateContentHeight(media: ArrayList<ThumbnailItem>) {
         val layoutManager = media_grid.layoutManager as MyGridLayoutManager
         val hasSections = config.getFolderGrouping(mPath) and GROUP_BY_NONE == 0 && !config.scrollHorizontally
-        val mSectionTitleHeight = if (hasSections) layoutManager.getChildAt(0)?.height ?: 0 else 0
-        val mThumbnailHeight = if (hasSections) layoutManager.getChildAt(1)?.height ?: 0 else layoutManager.getChildAt(0)?.height
+        val sectionTitleHeight = if (hasSections) layoutManager.getChildAt(0)?.height ?: 0 else 0
+        val thumbnailHeight = if (hasSections) layoutManager.getChildAt(1)?.height ?: 0 else layoutManager.getChildAt(0)?.height
                 ?: 0
 
         var fullHeight = 0
         var curSectionItems = 0
         media.forEach {
             if (it is ThumbnailSection) {
-                fullHeight += mSectionTitleHeight
+                fullHeight += sectionTitleHeight
                 if (curSectionItems != 0) {
                     val rows = ((curSectionItems - 1) / layoutManager.spanCount + 1)
-                    fullHeight += rows * mThumbnailHeight
+                    fullHeight += rows * thumbnailHeight
                 }
                 curSectionItems = 0
             } else {
@@ -631,7 +630,7 @@ class MediaActivity : SimpleActivity(), MediaAdapter.MediaOperationsListener {
             }
         }
 
-        fullHeight += ((curSectionItems - 1) / layoutManager.spanCount + 1) * mThumbnailHeight
+        fullHeight += ((curSectionItems - 1) / layoutManager.spanCount + 1) * thumbnailHeight
         media_vertical_fastscroller.setContentHeight(fullHeight)
         media_vertical_fastscroller.setScrollToY(media_grid.computeVerticalScrollOffset())
     }

app/src/main/kotlin/com/simplemobiletools/gallery/adapters/DirectoryAdapter.kt

@@ -255,7 +255,6 @@ class DirectoryAdapter(activity: BaseSimpleActivity, var dirs: ArrayList<Directo
                     dirs = newDirs
 
                     finishActMode()
-                    fastScroller?.measureRecyclerView()
                     listener?.updateDirectories(newDirs)
                 }
             }
@@ -423,7 +422,6 @@ class DirectoryAdapter(activity: BaseSimpleActivity, var dirs: ArrayList<Directo
             dirs = newDirs
             notifyDataSetChanged()
             finishActMode()
-            fastScroller?.measureRecyclerView()
         }
     }