sort construct list on construct list update, don't repeat sort operation

lib/pangea/models/analytics/construct_list_model.dart

@@ -52,16 +52,21 @@ class ConstructListModel {
     _updateMetrics();
   }
 
+  int _sortConstructs(ConstructUses a, ConstructUses b) {
+    final comp = b.points.compareTo(a.points);
+    if (comp != 0) return comp;
+    return a.lemma.compareTo(b.lemma);
+  }
+
   /// A map of lemmas to ConstructUses, each of which contains a lemma
   /// key = lemmma + constructType.string, value = ConstructUses
   void _updateConstructMap(final List<OneConstructUse> newUses) {
     for (final use in newUses) {
-      if (use.lemma == null) continue;
       final currentUses = _constructMap[use.identifier.string] ??
           ConstructUses(
             uses: [],
             constructType: use.constructType,
-            lemma: use.lemma!,
+            lemma: use.lemma,
             category: use.category,
           );
       currentUses.uses.add(use);
@@ -75,11 +80,7 @@ class ConstructListModel {
   void _updateConstructList() {
     // TODO check how expensive this is
     _constructList = _constructMap.values.toList();
-    _constructList.sort((a, b) {
+    _constructList.sort(_sortConstructs);
-      final comp = b.uses.length.compareTo(a.uses.length);
-      if (comp != 0) return comp;
-      return a.lemma.compareTo(b.lemma);
-    });
   }
 
   void _updateCategoriesToUses() {

lib/pangea/widgets/chat_list/analytics_summary/analytics_popup/analytics_popup.dart

@@ -1,4 +1,3 @@
-import 'package:collection/collection.dart';
 import 'package:fluffychat/pangea/enum/construct_type_enum.dart';
 import 'package:fluffychat/pangea/enum/progress_indicators_enum.dart';
 import 'package:fluffychat/pangea/models/analytics/construct_list_model.dart';
@@ -94,11 +93,7 @@ class AnalyticsPopupState extends State<AnalyticsPopup> {
       dialogContent = Center(child: Text(L10n.of(context)!.noDataFound));
     } else if (hasNoCategories || !widget.showGroups) {
       dialogContent = ConstructsTileList(
-        _constructsModel.constructList(type: widget.type).sorted((a, b) {
+        _constructsModel.constructList(type: widget.type),
-          final comp = b.points.compareTo(a.points);
-          if (comp != 0) return comp;
-          return a.lemma.compareTo(b.lemma);
-        }),
       );
     } else {
       dialogContent = ListView.builder(
@@ -156,8 +151,6 @@ class ConstructsTileList extends StatelessWidget {
 
   @override
   Widget build(BuildContext context) {
-    // sort list by xp
-    constructs.sort((a, b) => b.points.compareTo(a.points));
     return ListView.builder(
       itemCount: constructs.length,
       itemBuilder: (context, index) => ConstructUsesXPTile(constructs[index]),