handle deleting folders from local db

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

@@ -362,6 +362,11 @@ class MainActivity : SimpleActivity(), DirectoryAdapter.DirOperationsListener {
             runOnUiThread {
                 refreshItems()
             }
+            Thread {
+                folders.filter { !it.exists() }.forEach {
+                    galleryDB.DirectoryDao().deleteDirPath(it.absolutePath)
+                }
+            }.start()
         }
     }
 

app/src/main/kotlin/com/simplemobiletools/gallery/extensions/Activity.kt

@@ -246,7 +246,13 @@ fun Activity.loadJpg(path: String, target: MySquareImageView, cropThumbnails: Bo
 
 fun Activity.getCachedDirectories(callback: (ArrayList<Directory>) -> Unit) {
     Thread {
-        callback(galleryDB.DirectoryDao().getAll() as ArrayList<Directory>)
+        val directoryDao = galleryDB.DirectoryDao()
+        val directories = directoryDao.getAll() as ArrayList<Directory>
+        callback(directories)
+
+        directories.filter { !File(it.path).exists() }.forEach {
+            directoryDao.deleteDir(it)
+        }
     }.start()
 }
 

app/src/main/kotlin/com/simplemobiletools/gallery/interfaces/DirectoryDao.kt

@@ -1,6 +1,7 @@
 package com.simplemobiletools.gallery.interfaces
 
 import android.arch.persistence.room.Dao
+import android.arch.persistence.room.Delete
 import android.arch.persistence.room.Insert
 import android.arch.persistence.room.OnConflictStrategy.REPLACE
 import android.arch.persistence.room.Query
@@ -16,4 +17,10 @@ interface DirectoryDao {
 
     @Insert(onConflict = REPLACE)
     fun insertAll(directories: List<Directory>)
+
+    @Delete
+    fun deleteDir(directory: Directory)
+
+    @Query("DELETE FROM directories WHERE path = :path")
+    fun deleteDirPath(path: String)
 }