public Uri getUriForFolder(@NonNull final Folder folder) {
        final Uri folderUri = folderToUri(folder);
        if (new File(folderUri.getPath()).isDirectory()) {
            return folderUri;
        }
        return null;
    }
Must return null if folder does not yet exist
main/src/main/java/cgeo/geocaching/storage/FileContentAccessor.java