Support for persisting sort settings on device

lib/utils/local_settings.dart

@@ -0,0 +1,31 @@
+import 'package:logging/logging.dart';
+import 'package:shared_preferences/shared_preferences.dart';
+
+enum AlbumSortKey {
+  albumName,
+  lastModified,
+  createdAt,
+}
+
+class LocalSettings {
+  LocalSettings._privateConstructor();
+
+  static final LocalSettings instance = LocalSettings._privateConstructor();
+  static const kCollectionSortPref = "collection_sort_pref";
+
+  final _logger = Logger("FeatureFlagService");
+  SharedPreferences _prefs;
+
+  Future<void> init() async {
+    _prefs = await SharedPreferences.getInstance();
+  }
+
+  AlbumSortKey albumSortKey() {
+    return AlbumSortKey.values[_prefs.getInt(kCollectionSortPref)]
+  }
+
+  void setAlbumSortKey(AlbumSortKey key) {
+    _prefs.setInt(kCollectionSortPref, key.index);
+  }
+
+}