diff --git a/commons/src/main/kotlin/com/simplemobiletools/commons/activities/BaseSimpleActivity.kt b/commons/src/main/kotlin/com/simplemobiletools/commons/activities/BaseSimpleActivity.kt
index 6fbe816d2..6cb37ca49 100644
--- a/commons/src/main/kotlin/com/simplemobiletools/commons/activities/BaseSimpleActivity.kt
+++ b/commons/src/main/kotlin/com/simplemobiletools/commons/activities/BaseSimpleActivity.kt
@@ -221,12 +221,37 @@ abstract class BaseSimpleActivity : AppCompatActivity() {
         }
 
         Log.i(TAG, "onActivityResult: partition=$partition")
+        Log.i(TAG, "onActivityResult: checkedDocumentPath=$checkedDocumentPath")
+        Log.i(TAG, "onActivityResult: treeUri=${resultData?.data}")
         val sdOtgPattern = Pattern.compile(SD_OTG_SHORT)
 
-        if (requestCode == OPEN_DOCUMENT_TREE) {
+        if (requestCode == OPEN_DOCUMENT_TREE_PRIMARY) {
+            if (resultCode == Activity.RESULT_OK && resultData != null && resultData.data != null) {
+                if (isProperInternalRoot(resultData.data!!)) {
+                    if (resultData.dataString == baseConfig.primaryTreeUri) {
+                        toast(R.string.sd_card_usb_same)
+                        return
+                    }
+
+                    val treeUri = resultData.data
+                    baseConfig.primaryTreeUri = treeUri.toString()
+
+                    val takeFlags = Intent.FLAG_GRANT_READ_URI_PERMISSION or Intent.FLAG_GRANT_WRITE_URI_PERMISSION
+                    applicationContext.contentResolver.takePersistableUriPermission(treeUri!!, takeFlags)
+                    funAfterSAFPermission?.invoke(true)
+                    funAfterSAFPermission = null
+                } else {
+                    toast(R.string.wrong_root_selected)
+                    val intent = Intent(Intent.ACTION_OPEN_DOCUMENT_TREE)
+                    startActivityForResult(intent, requestCode)
+                }
+            } else {
+                funAfterSAFPermission?.invoke(false)
+            }
+        } else if (requestCode == OPEN_DOCUMENT_TREE_SD) {
             if (resultCode == Activity.RESULT_OK && resultData != null && resultData.data != null) {
                 val isProperPartition = partition.isEmpty() || !sdOtgPattern.matcher(partition).matches() || (sdOtgPattern.matcher(partition).matches() && resultData.dataString!!.contains(partition))
-                if (isAndroidDataRoot(checkedDocumentPath) || (isProperSDFolder(resultData.data!!) && isProperPartition)) {
+                if (isProperSDFolder(resultData.data!!) && isProperPartition) {
                     if (resultData.dataString == baseConfig.OTGTreeUri) {
                         toast(R.string.sd_card_usb_same)
                         return
@@ -247,7 +272,7 @@ abstract class BaseSimpleActivity : AppCompatActivity() {
             if (resultCode == Activity.RESULT_OK && resultData != null && resultData.data != null) {
                 val isProperPartition = partition.isEmpty() || !sdOtgPattern.matcher(partition).matches() || (sdOtgPattern.matcher(partition).matches() && resultData.dataString!!.contains(partition))
                 if (isProperOTGFolder(resultData.data!!) && isProperPartition) {
-                    if (resultData.dataString == baseConfig.treeUri) {
+                    if (resultData.dataString == baseConfig.sdTreeUri) {
                         funAfterSAFPermission?.invoke(false)
                         toast(R.string.sd_card_usb_same)
                         return
@@ -277,7 +302,7 @@ abstract class BaseSimpleActivity : AppCompatActivity() {
 
     private fun saveTreeUri(resultData: Intent) {
         val treeUri = resultData.data
-        baseConfig.treeUri = treeUri.toString()
+        baseConfig.sdTreeUri = treeUri.toString()
 
         val takeFlags = Intent.FLAG_GRANT_READ_URI_PERMISSION or Intent.FLAG_GRANT_WRITE_URI_PERMISSION
         applicationContext.contentResolver.takePersistableUriPermission(treeUri!!, takeFlags)
@@ -287,7 +312,10 @@ abstract class BaseSimpleActivity : AppCompatActivity() {
 
     private fun isProperOTGFolder(uri: Uri) = isExternalStorageDocument(uri) && isRootUri(uri) && !isInternalStorage(uri)
 
-    private fun isRootUri(uri: Uri) = DocumentsContract.getTreeDocumentId(uri).endsWith(":")
+    @SuppressLint("NewApi")
+    private fun isProperInternalRoot(uri: Uri) = isExternalStorageDocument(uri) && isRootUri(uri) && isInternalStorage(uri)
+
+    private fun isRootUri(uri: Uri) = uri.lastPathSegment?.endsWith(":") ?: false
 
     private fun isInternalStorage(uri: Uri) = isExternalStorageDocument(uri) && DocumentsContract.getTreeDocumentId(uri).contains("primary")
 
@@ -354,6 +382,19 @@ abstract class BaseSimpleActivity : AppCompatActivity() {
         }
     }
 
+    fun handlePrimarySAFDialog(path: String, callback: (success: Boolean) -> Unit): Boolean {
+        return if (!packageName.startsWith("com.simplemobiletools")) {
+            callback(true)
+            false
+        } else if (isShowingSAFPrimaryDialog(path)) {
+            funAfterSAFPermission = callback
+            true
+        } else {
+            callback(true)
+            false
+        }
+    }
+
     fun handleOTGPermission(callback: (success: Boolean) -> Unit) {
         if (baseConfig.OTGTreeUri.isNotEmpty()) {
             callback(true)
diff --git a/commons/src/main/kotlin/com/simplemobiletools/commons/extensions/Activity.kt b/commons/src/main/kotlin/com/simplemobiletools/commons/extensions/Activity.kt
index bcabfd070..bdae8ded0 100644
--- a/commons/src/main/kotlin/com/simplemobiletools/commons/extensions/Activity.kt
+++ b/commons/src/main/kotlin/com/simplemobiletools/commons/extensions/Activity.kt
@@ -36,13 +36,13 @@ import com.simplemobiletools.commons.dialogs.*
 import com.simplemobiletools.commons.helpers.*
 import com.simplemobiletools.commons.models.*
 import com.simplemobiletools.commons.views.MyTextView
-import kotlinx.android.synthetic.main.dialog_title.view.*
 import java.io.File
 import java.io.FileNotFoundException
 import java.io.FileOutputStream
 import java.io.OutputStream
 import java.util.*
 import kotlin.collections.HashMap
+import kotlinx.android.synthetic.main.dialog_title.view.*
 
 fun AppCompatActivity.updateActionBarTitle(text: String, color: Int = baseConfig.primaryColor) {
     supportActionBar?.title = Html.fromHtml("<font color='${color.getContrastColor().toHex()}'>$text</font>")
@@ -117,14 +117,14 @@ fun Activity.isAppInstalledOnSDCard(): Boolean = try {
 }
 
 fun BaseSimpleActivity.isShowingSAFDialog(path: String): Boolean {
-    return if (((isPathOnSD(path) || isAndroidDataRoot(path))  && !isSDCardSetAsDefaultStorage() && (baseConfig.treeUri.isEmpty() || !hasProperStoredTreeUri(false)))) {
+    return if ((isPathOnSD(path) && !isSDCardSetAsDefaultStorage() && (baseConfig.sdTreeUri.isEmpty() || !hasProperStoredTreeUri(false)))) {
         runOnUiThread {
             if (!isDestroyed && !isFinishing) {
                 WritePermissionDialog(this, false) {
                     Intent(Intent.ACTION_OPEN_DOCUMENT_TREE).apply {
                         putExtra("android.content.extra.SHOW_ADVANCED", true)
                         try {
-                            startActivityForResult(this, OPEN_DOCUMENT_TREE)
+                            startActivityForResult(this, OPEN_DOCUMENT_TREE_SD)
                             checkedDocumentPath = path
                             return@apply
                         } catch (e: Exception) {
@@ -132,7 +132,38 @@ fun BaseSimpleActivity.isShowingSAFDialog(path: String): Boolean {
                         }
 
                         try {
-                            startActivityForResult(this, OPEN_DOCUMENT_TREE)
+                            startActivityForResult(this, OPEN_DOCUMENT_TREE_SD)
+                            checkedDocumentPath = path
+                        } catch (e: Exception) {
+                            toast(R.string.unknown_error_occurred)
+                        }
+                    }
+                }
+            }
+        }
+        true
+    } else {
+        false
+    }
+}
+
+fun BaseSimpleActivity.isShowingSAFPrimaryDialog(path: String): Boolean {
+    return if (isSAFOnlyRoot(path) && (baseConfig.primaryTreeUri.isEmpty() || !hasProperStoredPrimaryTreeUri())) {
+        runOnUiThread {
+            if (!isDestroyed && !isFinishing) {
+                WritePermissionDialog(this, false) {
+                    Intent(Intent.ACTION_OPEN_DOCUMENT_TREE).apply {
+                        putExtra("android.content.extra.SHOW_ADVANCED", true)
+                        try {
+                            startActivityForResult(this, OPEN_DOCUMENT_TREE_PRIMARY)
+                            checkedDocumentPath = path
+                            return@apply
+                        } catch (e: Exception) {
+                            type = "*/*"
+                        }
+
+                        try {
+                            startActivityForResult(this, OPEN_DOCUMENT_TREE_PRIMARY)
                             checkedDocumentPath = path
                         } catch (e: Exception) {
                             toast(R.string.unknown_error_occurred)
@@ -496,7 +527,7 @@ fun BaseSimpleActivity.deleteFoldersBg(folders: List<FileDirItem>, deleteMediaOn
     var wasSuccess = false
     var needPermissionForPath = ""
     for (folder in folders) {
-        if (needsStupidWritePermissions(folder.path) && baseConfig.treeUri.isEmpty()) {
+        if (needsStupidWritePermissions(folder.path) && baseConfig.sdTreeUri.isEmpty()) {
             needPermissionForPath = folder.path
             break
         }
@@ -818,7 +849,7 @@ fun BaseSimpleActivity.getFileOutputStream(fileDirItem: FileDirItem, allowCreati
 
 fun BaseSimpleActivity.showFileCreateError(path: String) {
     val error = String.format(getString(R.string.could_not_create_file), path)
-    baseConfig.treeUri = ""
+    baseConfig.sdTreeUri = ""
     showErrorToast(error)
 }
 
diff --git a/commons/src/main/kotlin/com/simplemobiletools/commons/extensions/Context-storage.kt b/commons/src/main/kotlin/com/simplemobiletools/commons/extensions/Context-storage.kt
index 065d039f1..29c468966 100644
--- a/commons/src/main/kotlin/com/simplemobiletools/commons/extensions/Context-storage.kt
+++ b/commons/src/main/kotlin/com/simplemobiletools/commons/extensions/Context-storage.kt
@@ -12,8 +12,8 @@ import android.os.Environment
 import android.os.Handler
 import android.os.Looper
 import android.provider.DocumentsContract
+import android.provider.DocumentsContract.Document
 import android.provider.MediaStore.*
-import android.provider.OpenableColumns
 import android.text.TextUtils
 import androidx.annotation.RequiresApi
 import androidx.core.content.FileProvider
@@ -26,13 +26,19 @@ import java.io.File
 import java.io.FileInputStream
 import java.io.InputStream
 import java.net.URLDecoder
-import java.util.*
+import java.util.ArrayList
+import java.util.Collections
+import java.util.HashMap
+import java.util.HashSet
 import java.util.regex.Pattern
 
 // http://stackoverflow.com/a/40582634/1967672
 fun Context.getSDCardPath(): String {
     val directories = getStorageDirectories().filter {
-        !it.equals(getInternalStoragePath()) && !it.equals("/storage/emulated/0", true) && (baseConfig.OTGPartition.isEmpty() || !it.endsWith(baseConfig.OTGPartition))
+        !it.equals(getInternalStoragePath()) && !it.equals(
+            "/storage/emulated/0",
+            true
+        ) && (baseConfig.OTGPartition.isEmpty() || !it.endsWith(baseConfig.OTGPartition))
     }
 
     val fullSDpattern = Pattern.compile(SD_OTG_PATTERN)
@@ -121,12 +127,14 @@ fun Context.getStorageDirectories(): Array<String> {
 }
 
 fun Context.getHumanReadablePath(path: String): String {
-    return getString(when (path) {
-        "/" -> R.string.root
-        internalStoragePath -> R.string.internal
-        otgPath -> R.string.usb
-        else -> R.string.sd_card
-    })
+    return getString(
+        when (path) {
+            "/" -> R.string.root
+            internalStoragePath -> R.string.internal
+            otgPath -> R.string.usb
+            else -> R.string.sd_card
+        }
+    )
 }
 
 fun Context.humanizePath(path: String): String {
@@ -138,14 +146,24 @@ fun Context.humanizePath(path: String): String {
     }
 }
 
-fun Context.getInternalStoragePath() = if (File("/storage/emulated/0").exists()) "/storage/emulated/0" else Environment.getExternalStorageDirectory().absolutePath.trimEnd('/')
+fun Context.getInternalStoragePath() =
+    if (File("/storage/emulated/0").exists()) "/storage/emulated/0" else Environment.getExternalStorageDirectory().absolutePath.trimEnd('/')
 
 fun Context.isPathOnSD(path: String) = sdCardPath.isNotEmpty() && path.startsWith(sdCardPath)
 
 fun Context.isPathOnOTG(path: String) = otgPath.isNotEmpty() && path.startsWith(otgPath)
 
-fun Context.isAndroidDataRoot(path: String) = (path == (internalStoragePath.plus(ANDROID_DIR)) || path == otgPath.plus(ANDROID_DIR) || path == sdCardPath.plus(ANDROID_DIR))
+val DIRS_ACCESSIBLE_ONLY_WITH_SAF = listOf("/Android")
 
+fun Context.getSAFOnlyDirs(): List<String> {
+    return DIRS_ACCESSIBLE_ONLY_WITH_SAF.map { "$internalStoragePath$it" }
+}
+
+fun Context.isSAFOnlyRoot(path: String): Boolean {
+    val dirs = getSAFOnlyDirs()
+    val result = dirs.any { path.startsWith(it) }
+    return result
+}
 
 // no need to use DocumentFile if an SD card is set as the default storage
 fun Context.needsStupidWritePermissions(path: String) = (isPathOnSD(path) || isPathOnOTG(path)) && !isSDCardSetAsDefaultStorage()
@@ -153,18 +171,27 @@ fun Context.needsStupidWritePermissions(path: String) = (isPathOnSD(path) || isP
 fun Context.isSDCardSetAsDefaultStorage() = sdCardPath.isNotEmpty() && Environment.getExternalStorageDirectory().absolutePath.equals(sdCardPath, true)
 
 fun Context.hasProperStoredTreeUri(isOTG: Boolean): Boolean {
-    val uri = if (isOTG) baseConfig.OTGTreeUri else baseConfig.treeUri
+    val uri = if (isOTG) baseConfig.OTGTreeUri else baseConfig.sdTreeUri
     val hasProperUri = contentResolver.persistedUriPermissions.any { it.uri.toString() == uri }
     if (!hasProperUri) {
         if (isOTG) {
             baseConfig.OTGTreeUri = ""
         } else {
-            baseConfig.treeUri = ""
+            baseConfig.sdTreeUri = ""
         }
     }
     return hasProperUri
 }
 
+fun Context.hasProperStoredPrimaryTreeUri(): Boolean {
+    val uri = baseConfig.primaryTreeUri
+    val hasProperUri = contentResolver.persistedUriPermissions.any { it.uri.toString() == uri }
+    if (!hasProperUri) {
+        baseConfig.primaryTreeUri = ""
+    }
+    return hasProperUri
+}
+
 fun Context.isAStorageRootFolder(path: String): Boolean {
     val trimmed = path.trimEnd('/')
     return trimmed.isEmpty() || trimmed.equals(internalStoragePath, true) || trimmed.equals(sdCardPath, true) || trimmed.equals(otgPath, true)
@@ -202,7 +229,7 @@ fun Context.getFastDocumentFile(path: String): DocumentFile? {
 
     val relativePath = Uri.encode(path.substring(baseConfig.sdCardPath.length).trim('/'))
     val externalPathPart = baseConfig.sdCardPath.split("/").lastOrNull(String::isNotEmpty)?.trim('/') ?: return null
-    val fullUri = "${baseConfig.treeUri}/document/$externalPathPart%3A$relativePath"
+    val fullUri = "${baseConfig.sdTreeUri}/document/$externalPathPart%3A$relativePath"
     return DocumentFile.fromSingleUri(this, Uri.parse(fullUri))
 }
 
@@ -230,7 +257,7 @@ fun Context.getDocumentFile(path: String): DocumentFile? {
     }
 
     return try {
-        val treeUri = Uri.parse(if (isOTG) baseConfig.OTGTreeUri else baseConfig.treeUri)
+        val treeUri = Uri.parse(if (isOTG) baseConfig.OTGTreeUri else baseConfig.sdTreeUri)
         var document = DocumentFile.fromTreeUri(applicationContext, treeUri)
         val parts = relativePath.split("/").filter { it.isNotEmpty() }
         for (part in parts) {
@@ -447,60 +474,90 @@ fun Context.getOTGItems(path: String, shouldShowHidden: Boolean, getProperFileSi
     callback(items)
 }
 
-const val MIME_TYPE_IS_DIRECTORY = "vnd.android.document/directory"
 
 @RequiresApi(Build.VERSION_CODES.O)
-fun Context.getStorageItems(path: String, shouldShowHidden: Boolean, getProperFileSize: Boolean, callback: (ArrayList<FileDirItem>) -> Unit) {
+fun Context.getStorageItemsWithTreeUri(path: String, shouldShowHidden: Boolean, getProperFileSize: Boolean, callback: (ArrayList<FileDirItem>) -> Unit) {
     val items = ArrayList<FileDirItem>()
-    val treeUri = baseConfig.treeUri
-    val document = getFastDocumentFile(path)
-    val files = document?.listFiles()
-    val childrenUri  = try {
-         DocumentsContract.buildChildDocumentsUriUsingTree(treeUri.toUri(), document?.uri.toString())
+    val rootDocumentFile = try {
+        DocumentFile.fromTreeUri(applicationContext, baseConfig.primaryTreeUri.toUri())
     } catch (e: Exception) {
         showErrorToast(e)
-        baseConfig.treeUri = ""
+        baseConfig.primaryTreeUri = ""
         null
     }
-    if (childrenUri == null) {
+
+    if (rootDocumentFile == null) {
         callback(items)
         return
     }
 
-    contentResolver.query(childrenUri, null, null, null)
-        ?.use { cursor ->
-            val nameIndex = cursor.getColumnIndex(OpenableColumns.DISPLAY_NAME)
-            val mimeIndex = cursor.getColumnIndex("mime_type")
-            while (cursor.moveToNext()) {
-                val name = cursor.getString(nameIndex) ?: continue
+    val treeUri = baseConfig.primaryTreeUri.toUri()
+    // uri should be a concatenation of the tree uri and the path without the internal storage path
+    val relativePath = path.substring(baseConfig.internalStoragePath.length).trim('/')
+    val documentId = "primary:$relativePath"
+    val childrenUri = DocumentsContract.buildChildDocumentsUriUsingTree(treeUri, documentId)
+    val projection = arrayOf(Document.COLUMN_DOCUMENT_ID, Document.COLUMN_DISPLAY_NAME, Document.COLUMN_MIME_TYPE)
+
+    val rawCursor = contentResolver.query(childrenUri, projection, null, null)!!
+    val cursor = ExternalStorageProviderHack.transformQueryResult(childrenUri, rawCursor)
+    cursor.use {
+        if (cursor.moveToFirst()) {
+            do {
+                val documentId = cursor.getStringValue(Document.COLUMN_DOCUMENT_ID)
+                val name = cursor.getStringValue(Document.COLUMN_DISPLAY_NAME)
+                val mimeType = cursor.getStringValue(Document.COLUMN_MIME_TYPE)
+                val isDirectory = mimeType == Document.MIME_TYPE_DIR
+                val filePath = documentId.substring("primary:".length)
                 if (!shouldShowHidden && name.startsWith(".")) {
                     continue
                 }
 
-                val mimeType = cursor.getString(mimeIndex)
-                val isDirectory = mimeType == MIME_TYPE_IS_DIRECTORY
-
+                val decodedPath = internalStoragePath + "/" + URLDecoder.decode(filePath, "UTF-8")
                 val fileSize = when {
-                    getProperFileSize -> 0L
+                    getProperFileSize -> getFileSize(treeUri, documentId)
                     isDirectory -> 0L
-                    else -> 0L
+                    else -> getFileSize(treeUri, documentId)
                 }
 
                 val childrenCount = if (isDirectory) {
-                    0
+                    getChildrenCount(treeUri, documentId)
                 } else {
                     0
                 }
 
-                val lastModified = 0L
-                val fileDirItem = FileDirItem(path, name, isDirectory, childrenCount, fileSize, lastModified)
+                val lastModified = System.currentTimeMillis()
+                val fileDirItem = FileDirItem(decodedPath, name, isDirectory, childrenCount, fileSize, lastModified)
                 items.add(fileDirItem)
-            }
+            } while (cursor.moveToNext())
         }
-
+    }
     callback(items)
 }
 
+fun Context.getChildrenCount(treeUri: Uri, documentId: String): Int {
+    val projection = arrayOf(Document.COLUMN_DOCUMENT_ID)
+    val childrenUri = DocumentsContract.buildChildDocumentsUriUsingTree(treeUri, documentId)
+    val rawCursor = contentResolver.query(childrenUri, projection, null, null, null)!!
+    val cursor = ExternalStorageProviderHack.transformQueryResult(childrenUri, rawCursor)
+    val count = cursor.count
+    return count
+}
+
+fun Context.getFileSize(treeUri: Uri, documentId: String): Long {
+    val projection = arrayOf(Document.COLUMN_SIZE)
+    val childrenUri = DocumentsContract.buildChildDocumentsUriUsingTree(treeUri, documentId)
+    val rawCursor = contentResolver.query(childrenUri, projection, null, null, null)!!
+    val cursor = ExternalStorageProviderHack.transformQueryResult(childrenUri, rawCursor)
+    var size = 0L
+    cursor.use { c ->
+        if (c.moveToFirst()) {
+            size = c.getLongValue(Document.COLUMN_SIZE)
+        }
+    }
+    return size
+}
+
+
 fun Context.trySAFFileDelete(fileDirItem: FileDirItem, allowDeleteFolder: Boolean = false, callback: ((wasSuccess: Boolean) -> Unit)? = null) {
     var fileDeleted = tryFastDocumentDelete(fileDirItem.path, allowDeleteFolder)
     if (!fileDeleted) {
@@ -509,7 +566,7 @@ fun Context.trySAFFileDelete(fileDirItem: FileDirItem, allowDeleteFolder: Boolea
             try {
                 fileDeleted = (document.isFile || allowDeleteFolder) && DocumentsContract.deleteDocument(applicationContext.contentResolver, document.uri)
             } catch (ignored: Exception) {
-                baseConfig.treeUri = ""
+                baseConfig.sdTreeUri = ""
                 baseConfig.sdCardPath = ""
             }
         }
diff --git a/commons/src/main/kotlin/com/simplemobiletools/commons/extensions/Context.kt b/commons/src/main/kotlin/com/simplemobiletools/commons/extensions/Context.kt
index f402a594e..adcc89660 100644
--- a/commons/src/main/kotlin/com/simplemobiletools/commons/extensions/Context.kt
+++ b/commons/src/main/kotlin/com/simplemobiletools/commons/extensions/Context.kt
@@ -55,7 +55,9 @@ import com.simplemobiletools.commons.models.SharedTheme
 import com.simplemobiletools.commons.views.*
 import java.io.File
 import java.text.SimpleDateFormat
-import java.util.*
+import java.util.ArrayList
+import java.util.Date
+import java.util.Locale
 
 fun Context.getSharedPrefs() = getSharedPreferences(PREFS_KEY, Context.MODE_PRIVATE)
 
@@ -489,7 +491,7 @@ fun Context.updateSDCardPath() {
         val oldPath = baseConfig.sdCardPath
         baseConfig.sdCardPath = getSDCardPath()
         if (oldPath != baseConfig.sdCardPath) {
-            baseConfig.treeUri = ""
+            baseConfig.sdTreeUri = ""
         }
     }
 }
diff --git a/commons/src/main/kotlin/com/simplemobiletools/commons/helpers/BaseConfig.kt b/commons/src/main/kotlin/com/simplemobiletools/commons/helpers/BaseConfig.kt
index 620b12b8b..5b64915b9 100644
--- a/commons/src/main/kotlin/com/simplemobiletools/commons/helpers/BaseConfig.kt
+++ b/commons/src/main/kotlin/com/simplemobiletools/commons/helpers/BaseConfig.kt
@@ -7,7 +7,9 @@ import com.simplemobiletools.commons.extensions.getInternalStoragePath
 import com.simplemobiletools.commons.extensions.getSDCardPath
 import com.simplemobiletools.commons.extensions.getSharedPrefs
 import java.text.SimpleDateFormat
-import java.util.*
+import java.util.Calendar
+import java.util.HashSet
+import java.util.Locale
 
 open class BaseConfig(val context: Context) {
     protected val prefs = context.getSharedPrefs()
@@ -24,9 +26,13 @@ open class BaseConfig(val context: Context) {
         get() = prefs.getInt(LAST_VERSION, 0)
         set(lastVersion) = prefs.edit().putInt(LAST_VERSION, lastVersion).apply()
 
-    var treeUri: String
-        get() = prefs.getString(TREE_URI, "")!!
-        set(uri) = prefs.edit().putString(TREE_URI, uri).apply()
+    var primaryTreeUri: String
+        get() = prefs.getString(PRIMARY_TREE_URI, "")!!
+        set(uri) = prefs.edit().putString(PRIMARY_TREE_URI, uri).apply()
+
+    var sdTreeUri: String
+        get() = prefs.getString(SD_TREE_URI, "")!!
+        set(uri) = prefs.edit().putString(SD_TREE_URI, uri).apply()
 
     var OTGTreeUri: String
         get() = prefs.getString(OTG_TREE_URI, "")!!
diff --git a/commons/src/main/kotlin/com/simplemobiletools/commons/helpers/Constants.kt b/commons/src/main/kotlin/com/simplemobiletools/commons/helpers/Constants.kt
index 6e3c010c1..2084be226 100644
--- a/commons/src/main/kotlin/com/simplemobiletools/commons/helpers/Constants.kt
+++ b/commons/src/main/kotlin/com/simplemobiletools/commons/helpers/Constants.kt
@@ -8,7 +8,8 @@ import android.os.Looper
 import android.util.Log
 import com.simplemobiletools.commons.R
 import com.simplemobiletools.commons.overloads.times
-import java.util.*
+import java.util.HashMap
+import java.util.LinkedHashMap
 
 const val APP_NAME = "app_name"
 const val APP_LICENSES = "app_licenses"
@@ -61,7 +62,8 @@ const val YEAR_SECONDS = YEAR_MINUTES * 60
 const val PREFS_KEY = "Prefs"
 const val APP_RUN_COUNT = "app_run_count"
 const val LAST_VERSION = "last_version"
-const val TREE_URI = "tree_uri_2"
+const val SD_TREE_URI = "tree_uri_2"
+const val PRIMARY_TREE_URI = "primary_tree_uri_2"
 const val OTG_TREE_URI = "otg_tree_uri_2"
 const val SD_CARD_PATH = "sd_card_path_2"
 const val OTG_REAL_PATH = "otg_real_path_2"
@@ -183,8 +185,9 @@ const val LICENSE_SMS_MMS = 134217728
 const val LICENSE_APNG = 268435456
 
 // global intents
-const val OPEN_DOCUMENT_TREE = 1000
+const val OPEN_DOCUMENT_TREE_PRIMARY = 1000
 const val OPEN_DOCUMENT_TREE_OTG = 1001
+const val OPEN_DOCUMENT_TREE_SD = 1002
 const val REQUEST_SET_AS = 1002
 const val REQUEST_EDIT_IMAGE = 1003
 const val SELECT_EXPORT_SETTINGS_FILE_INTENT = 1004
@@ -305,9 +308,6 @@ const val DATE_FORMAT_FOURTEEN = "yy/MM/dd"
 const val TIME_FORMAT_12 = "hh:mm a"
 const val TIME_FORMAT_24 = "HH:mm"
 
-//storage
-const val ANDROID_DIR = "/Android"
-
 val appIconColorStrings = arrayListOf(
     ".Red",
     ".Pink",
diff --git a/commons/src/main/kotlin/com/simplemobiletools/commons/helpers/ExternalStorageProviderHack.kt b/commons/src/main/kotlin/com/simplemobiletools/commons/helpers/ExternalStorageProviderHack.kt
new file mode 100644
index 000000000..849832892
--- /dev/null
+++ b/commons/src/main/kotlin/com/simplemobiletools/commons/helpers/ExternalStorageProviderHack.kt
@@ -0,0 +1,106 @@
+package com.simplemobiletools.commons.helpers
+
+import android.database.Cursor
+import android.database.MatrixCursor
+import android.database.MergeCursor
+import android.net.Uri
+import android.provider.DocumentsContract
+import com.simplemobiletools.commons.extensions.getStringValue
+
+// On Android 11, ExternalStorageProvider no longer returns Android/data and Android/obb as children
+// of the Android directory on primary storage. However, the two child directories are actually
+// still accessible.
+// https://github.com/zhanghai/MaterialFiles/blob/master/app/src/main/java/me/zhanghai/android/files/provider/document/resolver/ExternalStorageProviderPrimaryAndroidDataHack.kt
+object ExternalStorageProviderHack {
+    private const val EXTERNAL_STORAGE_PROVIDER_AUTHORITY = "com.android.externalstorage.documents"
+    private const val EXTERNAL_STORAGE_PROVIDER_PRIMARY_ANDROID_DOCUMENT_ID = "primary:Android"
+    private const val EXTERNAL_STORAGE_PROVIDER_PRIMARY_ANDROID_DATA_DOCUMENT_ID =
+        "primary:Android/data"
+    private const val EXTERNAL_STORAGE_PROVIDER_PRIMARY_ANDROID_DATA_DISPLAY_NAME = "data"
+    private const val EXTERNAL_STORAGE_PROVIDER_PRIMARY_ANDROID_OBB_DOCUMENT_ID =
+        "primary:Android/obb"
+    private const val EXTERNAL_STORAGE_PROVIDER_PRIMARY_ANDROID_OBB_DISPLAY_NAME = "obb"
+
+    private val CHILD_DOCUMENTS_CURSOR_COLUMN_NAMES = arrayOf(
+        DocumentsContract.Document.COLUMN_DOCUMENT_ID,
+        DocumentsContract.Document.COLUMN_DISPLAY_NAME,
+        DocumentsContract.Document.COLUMN_MIME_TYPE,
+        DocumentsContract.Document.COLUMN_LAST_MODIFIED,
+        DocumentsContract.Document.COLUMN_SIZE,
+    )
+
+    fun transformQueryResult(uri: Uri, cursor: Cursor): Cursor {
+        val documentId = DocumentsContract.getDocumentId(uri)
+        if (uri.authority == EXTERNAL_STORAGE_PROVIDER_AUTHORITY && documentId == EXTERNAL_STORAGE_PROVIDER_PRIMARY_ANDROID_DOCUMENT_ID) {
+            var hasDataRow = false
+            var hasObbRow = false
+            try {
+                while (cursor.moveToNext()) {
+                    when (cursor.getStringValue(DocumentsContract.Document.COLUMN_DOCUMENT_ID)) {
+                        EXTERNAL_STORAGE_PROVIDER_PRIMARY_ANDROID_DATA_DOCUMENT_ID ->
+                            hasDataRow = true
+                        EXTERNAL_STORAGE_PROVIDER_PRIMARY_ANDROID_OBB_DOCUMENT_ID ->
+                            hasObbRow = true
+                    }
+                    if (hasDataRow && hasObbRow) {
+                        break
+                    }
+                }
+            } finally {
+                cursor.moveToPosition(-1)
+            }
+            if (hasDataRow && hasObbRow) {
+                return cursor
+            }
+            val extraCursor = MatrixCursor(CHILD_DOCUMENTS_CURSOR_COLUMN_NAMES)
+            if (!hasDataRow) {
+                extraCursor.newRow()
+                    .add(
+                        DocumentsContract.Document.COLUMN_DOCUMENT_ID,
+                        EXTERNAL_STORAGE_PROVIDER_PRIMARY_ANDROID_DATA_DOCUMENT_ID
+                    )
+                    .add(
+                        DocumentsContract.Document.COLUMN_DISPLAY_NAME,
+                        EXTERNAL_STORAGE_PROVIDER_PRIMARY_ANDROID_DATA_DISPLAY_NAME
+                    )
+                    .add(
+                        DocumentsContract.Document.COLUMN_MIME_TYPE,
+                        DocumentsContract.Document.MIME_TYPE_DIR
+                    )
+                    .add(
+                        DocumentsContract.Document.COLUMN_LAST_MODIFIED,
+                       System.currentTimeMillis()
+                    )
+                    .add(
+                        DocumentsContract.Document.COLUMN_SIZE,
+                        0L
+                    )
+            }
+            if (!hasObbRow) {
+                extraCursor.newRow()
+                    .add(
+                        DocumentsContract.Document.COLUMN_DOCUMENT_ID,
+                        EXTERNAL_STORAGE_PROVIDER_PRIMARY_ANDROID_OBB_DOCUMENT_ID
+                    )
+                    .add(
+                        DocumentsContract.Document.COLUMN_DISPLAY_NAME,
+                        EXTERNAL_STORAGE_PROVIDER_PRIMARY_ANDROID_OBB_DISPLAY_NAME
+                    )
+                    .add(
+                        DocumentsContract.Document.COLUMN_MIME_TYPE,
+                        DocumentsContract.Document.MIME_TYPE_DIR
+                    )
+                    .add(
+                        DocumentsContract.Document.COLUMN_LAST_MODIFIED,
+                        System.currentTimeMillis()
+                    )
+                    .add(
+                        DocumentsContract.Document.COLUMN_SIZE,
+                        0L
+                    )
+            }
+            return MergeCursor(arrayOf(cursor, extraCursor))
+        }
+        return cursor
+    }
+}