update: minor improvement swapping lakes

app/lib/pages/default_page.dart

@@ -6,6 +6,7 @@ import 'package:liquid_pull_to_refresh/liquid_pull_to_refresh.dart';
 
 import '../consts.dart';
 import '../widgets/main_layout.dart';
+import '../widgets/choropleth_map.dart';
 import '../utils/custom_search_delegate.dart';
 
 class DefaultPage extends StatefulWidget {
@@ -66,6 +67,7 @@ class _DefaultPageState extends State<DefaultPage> {
                       setState(() {
                         print("SetState called!");
                         selectedLake = result;
+                        // NB update lastLake persistent variable
                         initialiseState(false);
                       });
                     }

app/lib/widgets/choropleth_map.dart

@@ -9,7 +9,8 @@ import '../data_classes.dart';
 /// The map is created using the Syncfusion Flutter Maps library and
 /// coordinates fetched from the server.
 class ChoroplethMap extends StatefulWidget {
-  const ChoroplethMap({Key? key,
+  const ChoroplethMap({
+    Key? key,
     required this.relation,
     required this.measurements,
     required this.onSelectionChanged,
@@ -20,64 +21,75 @@ class ChoroplethMap extends StatefulWidget {
   final void Function(int selectedIndex) onSelectionChanged;
 
   @override
-  _ChoroplethMapState createState() => _ChoroplethMapState();
+  ChoroplethMapState createState() => ChoroplethMapState();
 }
 
-class _ChoroplethMapState extends State<ChoroplethMap> {
+class ChoroplethMapState extends State<ChoroplethMap> {
   int selectedIndex = -1;            // Subdivision/map tile index
   late MapShapeSource dataSource;
   late final MapZoomPanBehavior _zoomPanBehavior = MapZoomPanBehavior();
   final List<SubDiv> _subdivisions = <SubDiv>[];
 
+  void updateDataSource() {
+    _initDataSource();
+  }
+
   @override
   void initState() {
     super.initState();
-    // Extract all _subdivisions from list of measurements
-    for (Measurement measurement in widget.measurements) {
-      for (SubDiv subdivision in measurement.subDivs) {
-        _subdivisions.add(subdivision);
+      _initDataSource();
+    }
+
+    void _initDataSource() {
+      _subdivisions.clear();
+
+      // Extract all _subdivisions from list of measurements
+      for (Measurement measurement in widget.measurements) {
+        for (SubDiv subdivision in measurement.subDivs) {
+          _subdivisions.add(subdivision);
+        }
       }
-    };
 
-    // Initialise data source
-    dataSource = MapShapeSource.memory(
-      widget.relation,
-      shapeDataField: 'sub_div_id',
-      dataCount: _subdivisions.length,
-      primaryValueMapper: (int index) => _subdivisions[index].sub_div_id,
-      shapeColorValueMapper: (int index) => _subdivisions[index].avgThickness, // NB will later be minThickness
-      shapeColorMappers: const [
+      dataSource = MapShapeSource.memory(
+        widget.relation,
+        shapeDataField: 'sub_div_id',
+        dataCount: _subdivisions.length,
+        primaryValueMapper: (int index) => _subdivisions[index].sub_div_id,
+        shapeColorValueMapper: (int index) => _subdivisions[index].avgThickness, // NB will later be minThickness
+        shapeColorMappers: const [
+          MapColorMapper(
+              from: -2,
+              to: -1,
+              color: Color(0xFF8C8C8C),
+              text: '>8'),
+        MapColorMapper(
+            from: 0,
+            to: 4,
+            color: Color(0xFFff0000),
+            text: '{0},{4}'),
         MapColorMapper(
-            from: -2,
-            to: -1,
-            color: Color(0xFF8C8C8C),
+            from: 4,
+            to: 6,
+            color: Color(0xffff6a00),
+            text: '6'),
+        MapColorMapper(
+            from: 6,
+            to: 8,
+            color: Color(0xFFb1ff00),
+            text: '8'),
+        MapColorMapper(
+            from: 8,
+            to: 400,
+            color: Color(0xFF00d6ff),
             text: '>8'),
-      MapColorMapper(
-          from: 0,
-          to: 4,
-          color: Color(0xFFff0000),
-          text: '{0},{4}'),
-      MapColorMapper(
-          from: 4,
-          to: 6,
-          color: Color(0xffff6a00),
-          text: '6'),
-      MapColorMapper(
-          from: 6,
-          to: 8,
-          color: Color(0xFFb1ff00),
-          text: '8'),
-      MapColorMapper(
-          from: 8,
-          to: 400,
-          color: Color(0xFF00d6ff),
-          text: '>8'),
-        ],
-    );
+          ],
+      );
   }
 
   @override
   Widget build(BuildContext context) {
+    updateDataSource();
+
     return Stack(
       children: [
         SfMapsTheme(

app/lib/widgets/main_layout.dart

@@ -75,7 +75,6 @@ class _MapContainerWidgetState extends State<MapContainerWidget> {
   Widget build(BuildContext context) {
     // Initialise selectedMarker to first element in markerList
     selectedSubDiv ??= widget.measurements[0].subDivs[0];
-
     checkAndSetLastUpdate();
 
     const double contPadding = 30; // Container padding space
@@ -107,7 +106,8 @@ class _MapContainerWidgetState extends State<MapContainerWidget> {
                       child: ChoroplethMap(
                         relation: widget.relation,
                         measurements: widget.measurements,
-                        onSelectionChanged: handleSelection,),
+                        onSelectionChanged: handleSelection,
+                      ),
                     ),
                   ),
                   SizedBox(