remove the static variables from the MediaAdapter

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

@@ -194,8 +194,8 @@ class MainActivity : SimpleActivity(), DirectoryAdapter.DirOperationsListener {
     }
 
     private fun checkIfColorChanged() {
-        if (getDirectoryAdapter().foregroundColor != config.primaryColor) {
+        if (getRecyclerAdapter().foregroundColor != config.primaryColor) {
-            getDirectoryAdapter().foregroundColor = config.primaryColor
+            getRecyclerAdapter().foregroundColor = config.primaryColor
             directories_fastscroller.updateHandleColor()
         }
     }
@@ -210,11 +210,7 @@ class MainActivity : SimpleActivity(), DirectoryAdapter.DirOperationsListener {
         }
     }
 
-    private fun getDirectoryAdapter() = (directories_grid.adapter as DirectoryAdapter)
+    private fun getRecyclerAdapter() = (directories_grid.adapter as DirectoryAdapter)
-
-    override fun itemLongClicked(position: Int) {
-        directories_grid.setDragSelectActive(position)
-    }
 
     private fun handleZooming() {
         val layoutManager = directories_grid.layoutManager as GridLayoutManager
@@ -223,23 +219,23 @@ class MainActivity : SimpleActivity(), DirectoryAdapter.DirOperationsListener {
             override fun zoomIn() {
                 if (layoutManager.spanCount > 1) {
                     reduceColumnCount()
-                    getDirectoryAdapter().actMode?.finish()
+                    getRecyclerAdapter().actMode?.finish()
                 }
             }
 
             override fun zoomOut() {
                 if (layoutManager.spanCount < 10) {
                     increaseColumnCount()
-                    getDirectoryAdapter().actMode?.finish()
+                    getRecyclerAdapter().actMode?.finish()
                 }
             }
 
             override fun selectItem(position: Int) {
-                getDirectoryAdapter().selectItem(position)
+                getRecyclerAdapter().selectItem(position)
             }
 
             override fun selectRange(initialSelection: Int, lastDraggedIndex: Int, minReached: Int, maxReached: Int) {
-                getDirectoryAdapter().selectRange(initialSelection, lastDraggedIndex, minReached, maxReached)
+                getRecyclerAdapter().selectRange(initialSelection, lastDraggedIndex, minReached, maxReached)
             }
         }
     }
@@ -355,6 +351,10 @@ class MainActivity : SimpleActivity(), DirectoryAdapter.DirOperationsListener {
         getDirectories()
     }
 
+    override fun itemLongClicked(position: Int) {
+        directories_grid.setDragSelectActive(position)
+    }
+
     private fun checkWhatsNewDialog() {
         arrayListOf<Release>().apply {
             add(Release(46, R.string.release_46))

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

@@ -94,11 +94,6 @@ class MediaActivity : SimpleActivity(), MediaAdapter.MediaOperationsListener {
         config.temporarilyShowHidden = false
     }
 
-    override fun onDestroy() {
-        super.onDestroy()
-        MediaAdapter.cleanup()
-    }
-
     private fun tryloadGallery() {
         if (hasWriteStoragePermission()) {
             val dirName = getHumanizedFilename(mPath)
@@ -170,7 +165,7 @@ class MediaActivity : SimpleActivity(), MediaAdapter.MediaOperationsListener {
     private fun toggleFilenameVisibility() {
         config.displayFileNames = !config.displayFileNames
         if (media_grid.adapter != null)
-            (media_grid.adapter as MediaAdapter).updateDisplayFilenames(config.displayFileNames)
+            getRecyclerAdapter().updateDisplayFilenames(config.displayFileNames)
     }
 
     private fun showSortingDialog() {
@@ -262,6 +257,8 @@ class MediaActivity : SimpleActivity(), MediaAdapter.MediaOperationsListener {
         getMedia()
     }
 
+    private fun getRecyclerAdapter() = (media_grid.adapter as MediaAdapter)
+
     private fun handleZooming() {
         val layoutManager = media_grid.layoutManager as GridLayoutManager
         layoutManager.spanCount = config.mediaColumnCnt
@@ -269,22 +266,23 @@ class MediaActivity : SimpleActivity(), MediaAdapter.MediaOperationsListener {
             override fun zoomIn() {
                 if (layoutManager.spanCount > 1) {
                     reduceColumnCount()
-                    MediaAdapter.actMode?.finish()
+                    getRecyclerAdapter().actMode?.finish()
                 }
             }
 
             override fun zoomOut() {
                 if (layoutManager.spanCount < 10) {
                     increaseColumnCount()
-                    MediaAdapter.actMode?.finish()
+                    getRecyclerAdapter().actMode?.finish()
                 }
             }
+
             override fun selectItem(position: Int) {
-                (media_grid.adapter as MediaAdapter).selectItem(position)
+                getRecyclerAdapter().selectItem(position)
             }
 
             override fun selectRange(initialSelection: Int, lastDraggedIndex: Int, minReached: Int, maxReached: Int) {
-                (media_grid.adapter as MediaAdapter).selectRange(initialSelection, lastDraggedIndex, minReached, maxReached)
+                getRecyclerAdapter().selectRange(initialSelection, lastDraggedIndex, minReached, maxReached)
             }
         }
     }

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

@@ -3,6 +3,7 @@ package com.simplemobiletools.gallery.adapters
 import android.os.Build
 import android.support.v7.view.ActionMode
 import android.support.v7.widget.RecyclerView
+import android.util.SparseArray
 import android.view.*
 import android.widget.FrameLayout
 import com.bignerdranch.android.multiselector.ModalMultiSelectorCallback
@@ -29,14 +30,14 @@ import java.util.*
 class DirectoryAdapter(val activity: SimpleActivity, val dirs: MutableList<Directory>, val listener: DirOperationsListener?, val itemClick: (Directory) -> Unit) :
         RecyclerView.Adapter<DirectoryAdapter.ViewHolder>() {
 
-    val views = ArrayList<View>()
-    val config = activity.config
-    var pinnedFolders = config.pinnedFolders
-    var itemViews: HashMap<Int, View> = HashMap()
-    val selectedPositions: HashSet<Int> = HashSet()
-    var actMode: ActionMode? = null
     val multiSelector = MultiSelector()
+    val config = activity.config
+
+    var actMode: ActionMode? = null
+    var itemViews = SparseArray<View>()
+    val selectedPositions = HashSet<Int>()
     var foregroundColor = 0
+    var pinnedFolders = config.pinnedFolders
 
     fun toggleItemSelection(select: Boolean, pos: Int) {
         if (itemViews[pos] != null)
@@ -79,8 +80,6 @@ class DirectoryAdapter(val activity: SimpleActivity, val dirs: MutableList<Direc
                 getProperView(itemView).foreground = foregroundColor.createSelector()
         }
 
-        override fun getItemViews(): HashMap<Int, View> = itemViews
-
         override fun getSelectedPositions(): HashSet<Int> = selectedPositions
     }
 
@@ -281,7 +280,7 @@ class DirectoryAdapter(val activity: SimpleActivity, val dirs: MutableList<Direc
         var needPermissionForPath = ""
         selectedPositions.forEach {
             val path = dirs[it].path
-            if (activity.needsStupidWritePermissions(path) && activity.config.treeUri.isEmpty()) {
+            if (activity.needsStupidWritePermissions(path) && config.treeUri.isEmpty()) {
                 needPermissionForPath = path
             }
         }
@@ -312,7 +311,7 @@ class DirectoryAdapter(val activity: SimpleActivity, val dirs: MutableList<Direc
 
     override fun onBindViewHolder(holder: ViewHolder, position: Int) {
         val dir = dirs[position]
-        views.add(holder.bindView(activity, multiSelectorMode, multiSelector, dir, position, pinnedFolders.contains(dir.path), listener))
+        itemViews.put(position, holder.bindView(activity, multiSelectorMode, multiSelector, dir, position, pinnedFolders.contains(dir.path), listener))
         holder.itemView.tag = holder
     }
 
@@ -365,7 +364,6 @@ class DirectoryAdapter(val activity: SimpleActivity, val dirs: MutableList<Direc
     class ViewHolder(val view: View, val adapter: MyAdapterListener, val itemClick: (Directory) -> (Unit)) : SwappingHolder(view, MultiSelector()) {
         fun bindView(activity: SimpleActivity, multiSelectorCallback: ModalMultiSelectorCallback, multiSelector: MultiSelector, directory: Directory, pos: Int,
                      isPinned: Boolean, listener: DirOperationsListener?): View {
-            adapter.getItemViews().put(pos, itemView)
             itemView.apply {
                 dir_name.text = directory.name
                 photo_cnt.text = directory.mediaCnt.toString()
@@ -410,8 +408,6 @@ class DirectoryAdapter(val activity: SimpleActivity, val dirs: MutableList<Direc
 
         fun setupItemForeground(itemView: View)
 
-        fun getItemViews(): HashMap<Int, View>
-
         fun getSelectedPositions(): HashSet<Int>
     }
 

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

@@ -3,6 +3,7 @@ package com.simplemobiletools.gallery.adapters
 import android.os.Build
 import android.support.v7.view.ActionMode
 import android.support.v7.widget.RecyclerView
+import android.util.SparseArray
 import android.view.*
 import android.widget.FrameLayout
 import com.bignerdranch.android.multiselector.ModalMultiSelectorCallback
@@ -26,17 +27,13 @@ class MediaAdapter(val activity: SimpleActivity, var media: MutableList<Medium>,
         RecyclerView.Adapter<MediaAdapter.ViewHolder>() {
 
     val multiSelector = MultiSelector()
-    val views = ArrayList<View>()
     val config = activity.config
 
-    companion object {
     var actMode: ActionMode? = null
-        var displayFilenames = false
+    var itemViews = SparseArray<View>()
-        var foregroundColor = 0
-        var backgroundColor = 0
-        var itemCnt = 0
-        var itemViews: HashMap<Int, View> = HashMap()
     val selectedPositions = HashSet<Int>()
+    var foregroundColor = 0
+    var displayFilenames = false
 
     fun toggleItemSelection(select: Boolean, pos: Int) {
         if (itemViews[pos] != null)
@@ -64,19 +61,26 @@ class MediaAdapter(val activity: SimpleActivity, var media: MutableList<Medium>,
     }
 
     fun updateTitle(cnt: Int) {
-            actMode?.title = "$cnt / $itemCnt"
+        actMode?.title = "$cnt / ${media.size}"
     }
 
-        fun cleanup() {
+    val adapterListener = object : MyAdapterListener {
-            itemViews.clear()
+        override fun toggleItemSelectionAdapter(select: Boolean, position: Int) {
-            selectedPositions.clear()
+            toggleItemSelection(select, position)
         }
+
+        override fun setupItemForeground(itemView: View) {
+            if (Build.VERSION.SDK_INT < Build.VERSION_CODES.M)
+                (getProperView(itemView) as FrameLayout).foreground = foregroundColor.createSelector()
+            else
+                getProperView(itemView).foreground = foregroundColor.createSelector()
+        }
+
+        override fun getSelectedPositions(): HashSet<Int> = selectedPositions
     }
 
     init {
         foregroundColor = config.primaryColor
-        backgroundColor = config.backgroundColor
-        itemCnt = media.size
     }
 
     val multiSelectorMode = object : ModalMultiSelectorCallback(multiSelector) {
@@ -229,7 +233,6 @@ class MediaAdapter(val activity: SimpleActivity, var media: MutableList<Medium>,
             media.removeAll(removeMedia)
             selectedPositions.clear()
             listener?.deleteFiles(files)
-            itemCnt = media.size
         }
     }
 
@@ -241,11 +244,11 @@ class MediaAdapter(val activity: SimpleActivity, var media: MutableList<Medium>,
 
     override fun onCreateViewHolder(parent: ViewGroup?, viewType: Int): ViewHolder {
         val view = LayoutInflater.from(parent?.context).inflate(R.layout.photo_video_item, parent, false)
-        return ViewHolder(view, itemClick)
+        return ViewHolder(view, adapterListener, itemClick)
     }
 
     override fun onBindViewHolder(holder: ViewHolder, position: Int) {
-        views.add(holder.bindView(activity, multiSelectorMode, multiSelector, media[position], position, listener))
+        itemViews.put(position, holder.bindView(activity, multiSelectorMode, multiSelector, media[position], position, listener, displayFilenames))
         holder.itemView.tag = holder
     }
 
@@ -305,40 +308,38 @@ class MediaAdapter(val activity: SimpleActivity, var media: MutableList<Medium>,
         }
     }
 
-    class ViewHolder(val view: View, val itemClick: (Medium) -> (Unit)) : SwappingHolder(view, MultiSelector()) {
+    class ViewHolder(val view: View, val adapter: MyAdapterListener, val itemClick: (Medium) -> (Unit)) : SwappingHolder(view, MultiSelector()) {
         fun bindView(activity: SimpleActivity, multiSelectorCallback: ModalMultiSelectorCallback, multiSelector: MultiSelector, medium: Medium,
-                     pos: Int, listener: MediaOperationsListener?): View {
+                     pos: Int, listener: MediaOperationsListener?, displayFilenames: Boolean): View {
-            itemViews.put(pos, itemView)
             itemView.apply {
                 play_outline.visibility = if (medium.video) View.VISIBLE else View.GONE
                 photo_name.beVisibleIf(displayFilenames)
                 photo_name.text = medium.name
-                toggleItemSelection(selectedPositions.contains(pos), pos)
+                adapter.toggleItemSelectionAdapter(adapter.getSelectedPositions().contains(pos), pos)
                 activity.loadImage(medium.path, medium_thumbnail)
 
                 setOnClickListener { viewClicked(multiSelector, medium, pos) }
                 setOnLongClickListener {
+                    if (listener != null) {
                         if (!multiSelector.isSelectable) {
                             activity.startSupportActionMode(multiSelectorCallback)
-                        toggleItemSelection(true, pos)
+                            adapter.toggleItemSelectionAdapter(true, pos)
                         }
 
-                    listener!!.itemLongClicked(pos)
+                        listener.itemLongClicked(pos)
+                    }
                     true
                 }
 
-                if (Build.VERSION.SDK_INT < Build.VERSION_CODES.M)
+                adapter.setupItemForeground(this)
-                    (getProperView(this) as FrameLayout).foreground = foregroundColor.createSelector()
-                else
-                    getProperView(this).foreground = foregroundColor.createSelector()
             }
             return itemView
         }
 
         fun viewClicked(multiSelector: MultiSelector, medium: Medium, pos: Int) {
             if (multiSelector.isSelectable) {
-                val isSelected = selectedPositions.contains(layoutPosition)
+                val isSelected = adapter.getSelectedPositions().contains(layoutPosition)
-                toggleItemSelection(!isSelected, pos)
+                adapter.toggleItemSelectionAdapter(!isSelected, pos)
             } else {
                 itemClick(medium)
             }
@@ -349,6 +350,14 @@ class MediaAdapter(val activity: SimpleActivity, var media: MutableList<Medium>,
         }
     }
 
+    interface MyAdapterListener {
+        fun toggleItemSelectionAdapter(select: Boolean, position: Int)
+
+        fun setupItemForeground(itemView: View)
+
+        fun getSelectedPositions(): HashSet<Int>
+    }
+
     interface MediaOperationsListener {
         fun refreshItems()