Correctly keep the state of NavigationIndicator

Author: bdlukaa

lib/src/controls/navigation/navigation_view/indicators.dart

@@ -75,7 +75,7 @@ class NavigationIndicatorState<T extends NavigationIndicator> extends State<T> {
   }
 
   bool get isSelected {
-    return pane.isSelected(pane.effectiveItems[itemIndex]);
+    return pane.isSelected(item);
   }
 
   Axis get axis {
@@ -94,15 +94,17 @@ class NavigationIndicatorState<T extends NavigationIndicator> extends State<T> {
     return InheritedNavigationView.of(context).oldIndex;
   }
 
+  PaneItem get item {
+    return pane.effectiveItems[itemIndex];
+  }
+
   /// The parent of this item, if any
   PaneItemExpander? get parent {
-    final items = InheritedNavigationView.of(context).pane!.effectiveItems;
+    final items = pane.effectiveItems;
 
     final expandableItems = items.whereType<PaneItemExpander>();
     if (expandableItems.isEmpty) return null;
 
-    final item =
-        InheritedNavigationView.of(context).pane!.effectiveItems[itemIndex];
     for (final expandable in expandableItems) {
       if (expandable.items.contains(item)) return expandable;
     }
@@ -256,9 +258,17 @@ class _StickyNavigationIndicatorState
       return;
     }
 
-    _old = PageStorage.of(context)?.readState(context) as int? ?? _old;
+    _old = (PageStorage.of(context)?.readState(
+          context,
+          identifier: 'oldIndex$itemIndex',
+        ) as num?)
+            ?.toInt() ??
+        _old;
 
-    if (_old == oldIndex) return;
+    // do not perform the animation twice
+    if (_old == oldIndex) {
+      return;
+    }
 
     if (isShowing) {
       if (isBelow) {
@@ -300,7 +310,11 @@ class _StickyNavigationIndicatorState
 
     _old = oldIndex;
     if (mounted) {
-      PageStorage.of(context)?.writeState(context, _old);
+      PageStorage.of(context)?.writeState(
+        context,
+        _old,
+        identifier: 'oldIndex$itemIndex',
+      );
       setState(() {});
     }
   }

lib/src/controls/navigation/navigation_view/pane_items.dart

@@ -596,12 +596,25 @@ class __PaneItemExpanderState extends State<_PaneItemExpander>
     return widget.displayMode != PaneDisplayMode.open;
   }
 
-  bool _open = false;
+  late bool _open;
   late AnimationController controller = AnimationController(
     vsync: this,
     duration: const Duration(milliseconds: 100),
   );
 
+  @override
+  void initState() {
+    super.initState();
+    _open = PageStorage.of(context)?.readState(
+          context,
+          identifier: 'paneItemExpanderOpen',
+        ) as bool? ??
+        false;
+    if (_open) {
+      controller.value = 1;
+    }
+  }
+
   @override
   void dispose() {
     controller.dispose();
@@ -611,6 +624,12 @@ class __PaneItemExpanderState extends State<_PaneItemExpander>
 
   void toggleOpen() {
     setState(() => _open = !_open);
+
+    PageStorage.of(context)?.writeState(
+      context,
+      _open,
+      identifier: 'paneItemExpanderOpen',
+    );
     if (useFlyout) {
       flyoutController.toggle();
     }
@@ -627,6 +646,12 @@ class __PaneItemExpanderState extends State<_PaneItemExpander>
     final theme = FluentTheme.of(context);
     final body = InheritedNavigationView.of(context);
 
+    _open = PageStorage.of(context)?.readState(
+          context,
+          identifier: 'paneItemExpanderOpen',
+        ) as bool? ??
+        _open;
+
     // Indexes
     // Ensure, if the child item is not visible, this is shown as the selected
     // item

lib/src/controls/surfaces/expander.dart

@@ -133,7 +133,10 @@ class ExpanderState extends State<Expander>
   void initState() {
     super.initState();
     _controller = AnimationController(vsync: this);
-    _open = PageStorage.of(context)?.readState(context) as bool? ??
+    _open = PageStorage.of(context)?.readState(
+          context,
+          identifier: 'expanderOpen',
+        ) as bool? ??
         widget.initiallyExpanded;
     if (_open == true) {
       _controller.value = 1;
@@ -166,7 +169,11 @@ class ExpanderState extends State<Expander>
       );
       _open = true;
     }
-    PageStorage.of(context)?.writeState(context, open);
+    PageStorage.of(context)?.writeState(
+      context,
+      open,
+      identifier: 'expanderOpen',
+    );
     widget.onStateChanged?.call(open);
     if (mounted) setState(() {});
   }