move the gallery database fetcher in a context extension

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

@@ -29,7 +29,6 @@ import com.simplemobiletools.gallery.BuildConfig
 import com.simplemobiletools.gallery.R
 import com.simplemobiletools.gallery.adapters.DirectoryAdapter
 import com.simplemobiletools.gallery.asynctasks.GetDirectoriesAsynctask
-import com.simplemobiletools.gallery.databases.GalleryDataBase
 import com.simplemobiletools.gallery.dialogs.ChangeSortingDialog
 import com.simplemobiletools.gallery.dialogs.FilterMediaDialog
 import com.simplemobiletools.gallery.extensions.*
@@ -63,7 +62,6 @@ class MainActivity : SimpleActivity(), DirectoryAdapter.DirOperationsListener {
     private var mTempShowHiddenHandler = Handler()
     private var mCurrAsyncTask: GetDirectoriesAsynctask? = null
     private var mZoomListener: MyRecyclerView.MyZoomListener? = null
-    private var mGalleryDB: GalleryDataBase? = null
 
     private var mStoredAnimateGifs = true
     private var mStoredCropThumbnails = true
@@ -91,7 +89,6 @@ class MainActivity : SimpleActivity(), DirectoryAdapter.DirOperationsListener {
         removeTempFolder()
         directories_refresh_layout.setOnRefreshListener { getDirectories() }
         mDirs = ArrayList()
-        mGalleryDB = GalleryDataBase.getInstance(applicationContext)
         storeStateVariables()
         checkWhatsNewDialog()
 
@@ -557,7 +554,7 @@ class MainActivity : SimpleActivity(), DirectoryAdapter.DirOperationsListener {
         if (!isFromCache) {
             Thread {
                 //checkFolderContentChange(newDirs)
-                mGalleryDB!!.DirectoryDao().insertAll(newDirs)
+                galleryDB.DirectoryDao().insertAll(newDirs)
             }.start()
         }
 

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

@@ -33,7 +33,6 @@ import com.simplemobiletools.commons.views.MyRecyclerView
 import com.simplemobiletools.gallery.R
 import com.simplemobiletools.gallery.adapters.MediaAdapter
 import com.simplemobiletools.gallery.asynctasks.GetMediaAsynctask
-import com.simplemobiletools.gallery.databases.GalleryDataBase
 import com.simplemobiletools.gallery.dialogs.ChangeSortingDialog
 import com.simplemobiletools.gallery.dialogs.ExcludeFolderDialog
 import com.simplemobiletools.gallery.dialogs.FilterMediaDialog
@@ -63,7 +62,6 @@ class MediaActivity : SimpleActivity(), MediaAdapter.MediaOperationsListener {
     private var mCurrAsyncTask: GetMediaAsynctask? = null
     private var mZoomListener: MyRecyclerView.MyZoomListener? = null
     private var mSearchMenuItem: MenuItem? = null
-    private var mGalleryDB: GalleryDataBase? = null
 
     private var mStoredAnimateGifs = true
     private var mStoredCropThumbnails = true
@@ -96,7 +94,6 @@ class MediaActivity : SimpleActivity(), MediaAdapter.MediaOperationsListener {
         }
 
         storeStateVariables()
-        mGalleryDB = GalleryDataBase.getInstance(applicationContext)
 
         if (mShowAll) {
             supportActionBar?.setDisplayHomeAsUpEnabled(false)
@@ -629,7 +626,7 @@ class MediaActivity : SimpleActivity(), MediaAdapter.MediaOperationsListener {
             mLatestMediaId = getLatestMediaId()
             mLatestMediaDateId = getLatestMediaByDateId()
             if (!isFromCache) {
-                mGalleryDB!!.MediumDao().insertAll(media)
+                galleryDB.MediumDao().insertAll(media)
             }
         }.start()
 

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

@@ -16,6 +16,7 @@ import com.simplemobiletools.gallery.R
 import com.simplemobiletools.gallery.activities.SettingsActivity
 import com.simplemobiletools.gallery.asynctasks.GetDirectoriesAsynctask
 import com.simplemobiletools.gallery.asynctasks.GetMediaAsynctask
+import com.simplemobiletools.gallery.databases.GalleryDataBase
 import com.simplemobiletools.gallery.helpers.Config
 import com.simplemobiletools.gallery.helpers.NOMEDIA
 import com.simplemobiletools.gallery.helpers.SAVE_DIRS_CNT
@@ -65,6 +66,8 @@ fun Context.launchSettings() {
 
 val Context.config: Config get() = Config.newInstance(applicationContext)
 
+val Context.galleryDB: GalleryDataBase get() = GalleryDataBase.getInstance(applicationContext)
+
 fun Context.movePinnedDirectoriesToFront(dirs: ArrayList<Directory>): ArrayList<Directory> {
     val foundFolders = ArrayList<Directory>()
     val pinnedFolders = config.pinnedFolders