improved performance and battery usage on older devices

lib/state/app/infrastructure/loadable_state/view/loadable_state_consumer.dart

@@ -69,7 +69,7 @@ class LoadableStateConsumer<
     // null mid-refetch, and toggling the RefreshIndicator on that signal would
     // rebuild the tree under the ListView and reset its scroll position.
     final content = SizedBox(
-      height: MediaQuery.of(context).size.height,
+      height: MediaQuery.sizeOf(context).height,
       child: hasContent
           ? child(typedData as TState, isLoading)
           : const SizedBox.shrink(),

lib/state/app/infrastructure/loadable_state/view/loadable_state_error_bar.dart

@@ -95,10 +95,12 @@ class _LoadableStateErrorBarTextState extends State<LoadableStateErrorBarText> {
   late Timer _rebuildTimer;
   @override
   void initState() {
-    _rebuildTimer = Timer.periodic(
-      const Duration(seconds: 10),
-      (timer) => setState(() {}),
-    );
+    // Only refresh the relative "last updated" text while this page is the
+    // visible one; offstage tabs and covered routes have tickers disabled.
+    _rebuildTimer = Timer.periodic(const Duration(seconds: 10), (timer) {
+      if (!mounted) return;
+      if (TickerMode.getValuesNotifier(context).value.enabled) setState(() {});
+    });
     super.initState();
   }
 

lib/state/app/infrastructure/loadable_state/view/loadable_state_primary_loading.dart

@@ -33,6 +33,9 @@ class _LoadableStatePrimaryLoadingState
     extends State<LoadableStatePrimaryLoading> {
   Timer? _slowHintTimer;
   bool _showSlowHint = false;
+  // An indeterminate spinner ticks every frame even at opacity 0, so it is
+  // unmounted once the fade-out finished instead of just being hidden.
+  late bool _spinnerMounted = widget.visible;
 
   @override
   void initState() {
@@ -44,6 +47,7 @@ class _LoadableStatePrimaryLoadingState
   void didUpdateWidget(covariant LoadableStatePrimaryLoading oldWidget) {
     super.didUpdateWidget(oldWidget);
     if (widget.visible != oldWidget.visible) _restartSlowHintTimer();
+    if (widget.visible) _spinnerMounted = true;
   }
 
   void _restartSlowHintTimer() {
@@ -62,43 +66,49 @@ class _LoadableStatePrimaryLoadingState
   }
 
   @override
-  Widget build(BuildContext context) {
+  Widget build(BuildContext context) => AnimatedOpacity(
+    opacity: widget.visible ? 1.0 : 0.0,
+    duration: LoadableStateConsumer.animationDuration,
+    curve: Curves.easeInOut,
+    onEnd: () {
+      if (!widget.visible && _spinnerMounted) {
+        setState(() => _spinnerMounted = false);
+      }
+    },
+    child: _spinnerMounted ? _spinner(context) : const SizedBox.shrink(),
+  );
+
+  Widget _spinner(BuildContext context) {
     final status =
         widget.statusText ??
         (_showSlowHint ? LoadableStatePrimaryLoading.slowHintText : null);
-
-    return AnimatedOpacity(
-      opacity: widget.visible ? 1.0 : 0.0,
-      duration: LoadableStateConsumer.animationDuration,
-      curve: Curves.easeInOut,
-      child: Center(
-        child: Column(
-          mainAxisSize: MainAxisSize.min,
-          children: [
-            const AppProgressIndicator.large(),
-            AnimatedSwitcher(
-              duration: LoadableStateConsumer.animationDuration,
-              child: status == null
-                  ? const SizedBox.shrink()
-                  : Padding(
-                      key: ValueKey(status),
-                      padding: const EdgeInsets.only(
-                        top: 16,
-                        left: 24,
-                        right: 24,
-                      ),
-                      child: Text(
-                        status,
-                        textAlign: TextAlign.center,
-                        style: TextStyle(
-                          fontSize: 13,
-                          color: Theme.of(context).hintColor,
-                        ),
+    return Center(
+      child: Column(
+        mainAxisSize: MainAxisSize.min,
+        children: [
+          const AppProgressIndicator.large(),
+          AnimatedSwitcher(
+            duration: LoadableStateConsumer.animationDuration,
+            child: status == null
+                ? const SizedBox.shrink()
+                : Padding(
+                    key: ValueKey(status),
+                    padding: const EdgeInsets.only(
+                      top: 16,
+                      left: 24,
+                      right: 24,
+                    ),
+                    child: Text(
+                      status,
+                      textAlign: TextAlign.center,
+                      style: TextStyle(
+                        fontSize: 13,
+                        color: Theme.of(context).hintColor,
                       ),
                     ),
-            ),
-          ],
-        ),
+                  ),
+          ),
+        ],
       ),
     );
   }