Reverse media order in ViewPager

Fixes #7354

src/org/thoughtcrime/securesms/MediaPreviewActivity.java

@@ -460,11 +460,10 @@ public class MediaPreviewActivity extends PassphraseRequiredActionBarActivity im
       View      itemView       = LayoutInflater.from(context).inflate(R.layout.media_view_page, container, false);
       MediaView mediaView      = itemView.findViewById(R.id.media_view);
       boolean   autoplay       = position == autoPlayPosition;
-      int       cursorPosition = getCursorPosition(position);
 
       autoPlayPosition = -1;
 
-      cursor.moveToPosition(cursorPosition);
+      cursor.moveToPosition(position);
 
       MediaRecord mediaRecord = MediaRecord.from(context, masterSecret, cursor);
 
@@ -491,7 +490,7 @@ public class MediaPreviewActivity extends PassphraseRequiredActionBarActivity im
     }
 
     public MediaItem getMediaItemFor(int position) {
-      cursor.moveToPosition(getCursorPosition(position));
+      cursor.moveToPosition(position);
       MediaRecord mediaRecord = MediaRecord.from(context, masterSecret, cursor);
       Address     address     = mediaRecord.getAddress();
 
@@ -509,10 +508,6 @@ public class MediaPreviewActivity extends PassphraseRequiredActionBarActivity im
       MediaView mediaView = mediaViews.get(position);
       if (mediaView != null) mediaView.pause();
     }
-
-    private int getCursorPosition(int position) {
-      return cursor.getCount() - 1 - position;
-    }
   }
 
   private static class MediaItem {

src/org/thoughtcrime/securesms/database/loaders/PagingMediaLoader.java

@@ -40,7 +40,7 @@ public class PagingMediaLoader extends AsyncLoader<Pair<Cursor, Integer>> {
       Uri          attachmentUri = PartAuthority.getAttachmentDataUri(attachmentId);
 
       if (attachmentUri.equals(uri)) {
-        return new Pair<>(cursor, cursor.getCount() - 1 - cursor.getPosition());
+        return new Pair<>(cursor, cursor.getPosition());
       }
     }