properly refresh thumbnails at changing column count

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

@@ -259,11 +259,13 @@ class MainActivity : SimpleActivity(), DirectoryAdapter.DirOperationsListener {
     private fun increaseColumnCount() {
         config.dirColumnCnt = ++(directories_grid.layoutManager as GridLayoutManager).spanCount
         invalidateOptionsMenu()
+        directories_grid.adapter.notifyDataSetChanged()
     }
 
     private fun reduceColumnCount() {
         config.dirColumnCnt = --(directories_grid.layoutManager as GridLayoutManager).spanCount
         invalidateOptionsMenu()
+        directories_grid.adapter.notifyDataSetChanged()
     }
 
     private fun isPickImageIntent(intent: Intent) = isPickIntent(intent) && (hasImageContentData(intent) || isImageType(intent))

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

@@ -335,11 +335,13 @@ class MediaActivity : SimpleActivity(), MediaAdapter.MediaOperationsListener {
     private fun increaseColumnCount() {
         config.mediaColumnCnt = ++(media_grid.layoutManager as GridLayoutManager).spanCount
         invalidateOptionsMenu()
+        media_grid.adapter.notifyDataSetChanged()
     }
 
     private fun reduceColumnCount() {
         config.mediaColumnCnt = --(media_grid.layoutManager as GridLayoutManager).spanCount
         invalidateOptionsMenu()
+        media_grid.adapter.notifyDataSetChanged()
     }
 
     private fun isSetWallpaperIntent() = intent.getBooleanExtra(SET_WALLPAPER_INTENT, false)

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

@@ -2,7 +2,7 @@
 <RelativeLayout
     xmlns:android="http://schemas.android.com/apk/res/android"
     android:id="@+id/dir_holder"
-    android:layout_width="match_parent"
+    android:layout_width="wrap_content"
     android:layout_height="wrap_content"
     android:padding="1px">
 

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

@@ -2,7 +2,7 @@
 <RelativeLayout
     xmlns:android="http://schemas.android.com/apk/res/android"
     android:id="@+id/media_item_holder"
-    android:layout_width="match_parent"
+    android:layout_width="wrap_content"
     android:layout_height="wrap_content"
     android:padding="1px">