use an improved way of file thumbnail caching

Author: tibbi

app/src/main/kotlin/com/simplemobiletools/filemanager/pro/adapters/DecompressItemsAdapter.kt

@@ -95,7 +95,7 @@ class DecompressItemsAdapter(activity: SimpleActivity, var listItems: MutableLis
             } else {
                 val drawable = fileDrawables.getOrElse(fileName.substringAfterLast(".").toLowerCase(), { fileDrawable })
                 val options = RequestOptions()
-                    .signature(listItem.mPath.getFileSignature())
+                    .signature(listItem.getKey())
                     .diskCacheStrategy(DiskCacheStrategy.RESOURCE)
                     .error(drawable)
                     .centerCrop()

app/src/main/kotlin/com/simplemobiletools/filemanager/pro/adapters/ItemsAdapter.kt

@@ -736,7 +736,7 @@ class ItemsAdapter(activity: SimpleActivity, var listItems: MutableList<ListItem
 
                     val drawable = fileDrawables.getOrElse(fileName.substringAfterLast(".").toLowerCase(), { fileDrawable })
                     val options = RequestOptions()
-                        .signature(listItem.mPath.getFileSignature())
+                        .signature(listItem.getKey())
                         .diskCacheStrategy(DiskCacheStrategy.RESOURCE)
                         .error(drawable)
                         .transform(CenterCrop(), RoundedCorners(10))

app/src/main/kotlin/com/simplemobiletools/filemanager/pro/fragments/ItemsFragment.kt

@@ -231,7 +231,7 @@ class ItemsFragment : Fragment(), ItemOperationsListener, Breadcrumbs.Breadcrumb
             return
         }
 
-        val lastModifieds = if (isRPlus()) context!!.getFolderLastModifieds(path) else HashMap()
+        val lastModifieds = context!!.getFolderLastModifieds(path)
         val isSortingBySize = context!!.config.getFolderSorting(currentPath) and SORT_BY_SIZE != 0
         if (files != null) {
             for (file in files) {

app/src/main/kotlin/com/simplemobiletools/filemanager/pro/models/ListItem.kt

@@ -1,6 +1,20 @@
 package com.simplemobiletools.filemanager.pro.models
 
+import com.bumptech.glide.signature.ObjectKey
 import com.simplemobiletools.commons.models.FileDirItem
+import java.io.File
 
 data class ListItem(val mPath: String, val mName: String = "", var mIsDirectory: Boolean = false, var mChildren: Int = 0, var mSize: Long = 0L, var mModified: Long = 0L,
-                    var isSectionTitle: Boolean) : FileDirItem(mPath, mName, mIsDirectory, mChildren, mSize, mModified)
+                    var isSectionTitle: Boolean) : FileDirItem(mPath, mName, mIsDirectory, mChildren, mSize, mModified) {
+    fun getSignature(): String {
+        val lastModified = if (modified > 1) {
+            modified
+        } else {
+            File(path).lastModified()
+        }
+
+        return "$path-$lastModified-$size"
+    }
+
+    fun getKey() = ObjectKey(getSignature())
+}