fix(motion): pause loading effects when hidden or motion is reduced

lib/screens/downloaded_album_screen.dart

@@ -38,6 +38,7 @@ import 'package:spotiflac_android/widgets/disc_separator_chip.dart';
 import 'package:spotiflac_android/widgets/album_detail_header.dart';
 import 'package:spotiflac_android/widgets/mornye_artist_header.dart';
 import 'package:spotiflac_android/widgets/motion_header_banner.dart';
+import 'package:spotiflac_android/widgets/app_loading_indicator.dart';
 
 class DownloadedAlbumScreen extends ConsumerStatefulWidget {
   final String albumName;
@@ -270,7 +271,7 @@ class _DownloadedAlbumScreenState extends ConsumerState<DownloadedAlbumScreen>
     if (tracks.isEmpty && tracksValue.isLoading) {
       return Scaffold(
         appBar: AppBar(title: Text(widget.albumName)),
-        body: const Center(child: CircularProgressIndicator()),
+        body: const Center(child: AppLoadingIndicator()),
       );
     }
 

lib/widgets/animation_utils.dart

@@ -28,7 +28,11 @@ class StaggeredListItem extends StatelessWidget {
 
   @override
   Widget build(BuildContext context) {
-    if (!animate || index >= maxAnimatedItems) return child;
+    if (!animate ||
+        index >= maxAnimatedItems ||
+        MediaQuery.disableAnimationsOf(context)) {
+      return child;
+    }
     final cappedIndex = index.clamp(0, maxAnimatedItems - 1);
     final delay = staggerDelay * cappedIndex;
     final totalDuration = duration + delay;
@@ -87,7 +91,18 @@ class _ShimmerLoadingState extends State<ShimmerLoading>
     _controller = AnimationController(
       vsync: this,
       duration: const Duration(milliseconds: 1200),
-    )..repeat();
+    );
+  }
+
+  @override
+  void didChangeDependencies() {
+    super.didChangeDependencies();
+    if (MediaQuery.disableAnimationsOf(context) ||
+        !TickerMode.valuesOf(context).enabled) {
+      _controller.stop();
+    } else if (!_controller.isAnimating) {
+      _controller.repeat();
+    }
   }
 
   @override
@@ -98,6 +113,7 @@ class _ShimmerLoadingState extends State<ShimmerLoading>
 
   @override
   Widget build(BuildContext context) {
+    if (MediaQuery.disableAnimationsOf(context)) return widget.child;
     final colorScheme = Theme.of(context).colorScheme;
     final isDark = Theme.of(context).brightness == Brightness.dark;
 

lib/widgets/app_loading_indicator.dart

@@ -1,6 +1,7 @@
 import 'package:flutter/material.dart';
 import 'package:material_3_expressive/material_3_expressive.dart';
 import 'package:spotiflac_android/theme/material_expressive.dart';
+import 'package:spotiflac_android/theme/mornye_theme.dart';
 
 /// Indeterminate loading only. Downloads/analysis keep their real progress.
 class AppLoadingIndicator extends StatelessWidget {
@@ -16,22 +17,31 @@ class AppLoadingIndicator extends StatelessWidget {
   final String? semanticLabel;
 
   @override
-  Widget build(BuildContext context) => SizedBox.square(
-    dimension: size,
-    child: materialExpressiveEnabled(context)
-        ? MaterialExpressiveScope(
-            child: FittedBox(
-              child: M3ELoadingIndicator(
-                size: 48,
+  Widget build(BuildContext context) {
+    final animate =
+        !MediaQuery.disableAnimationsOf(context) &&
+        TickerMode.valuesOf(context).enabled;
+    return SizedBox.square(
+      dimension: size,
+      child: !context.isMornye
+          ? MaterialExpressiveScope(
+              child: FittedBox(
+                child: M3ELoadingIndicator(
+                  size: 48,
+                  color: color,
+                  rotationTurns: animate ? null : 0,
+                  semanticLabel: semanticLabel,
+                ),
+              ),
+            )
+          : TickerMode(
+              enabled: animate,
+              child: CircularProgressIndicator(
                 color: color,
-                semanticLabel: semanticLabel,
+                strokeWidth: 3,
+                semanticsLabel: semanticLabel,
               ),
             ),
-          )
-        : CircularProgressIndicator(
-            color: color,
-            strokeWidth: 3,
-            semanticsLabel: semanticLabel,
-          ),
-  );
+    );
+  }
 }

test/loading_motion_preferences_test.dart

@@ -0,0 +1,74 @@
+import 'package:flutter/material.dart';
+import 'package:flutter_test/flutter_test.dart';
+import 'package:material_3_expressive/material_3_expressive.dart';
+import 'package:spotiflac_android/theme/app_theme.dart';
+import 'package:spotiflac_android/widgets/animation_utils.dart';
+import 'package:spotiflac_android/widgets/app_loading_indicator.dart';
+
+void main() {
+  for (final reduced in [false, true]) {
+    testWidgets(
+      'loading stops when ${reduced ? 'motion is reduced' : 'its tab is hidden'} and resumes',
+      (tester) async {
+        var stopped = false;
+        late StateSetter update;
+        await tester.pumpWidget(
+          MaterialApp(
+            theme: AppTheme.light(),
+            home: StatefulBuilder(
+              builder: (context, setState) {
+                update = setState;
+                return MediaQuery(
+                  data: MediaQuery.of(
+                    context,
+                  ).copyWith(disableAnimations: reduced && stopped),
+                  child: TickerMode(
+                    enabled: reduced || !stopped,
+                    child: const Column(
+                      children: [
+                        AppLoadingIndicator(semanticLabel: 'Loading'),
+                        ShimmerLoading(
+                          child: SkeletonBox(width: 100, height: 40),
+                        ),
+                      ],
+                    ),
+                  ),
+                );
+              },
+            ),
+          ),
+        );
+        await tester.pump(const Duration(milliseconds: 100));
+        expect(tester.binding.hasScheduledFrame, isTrue);
+        update(() => stopped = true);
+        await tester.pump();
+        await tester.pump(const Duration(seconds: 2));
+        expect(tester.binding.hasScheduledFrame, isFalse);
+        expect(find.byType(M3ELoadingIndicator), findsOneWidget);
+        if (reduced) expect(find.byType(ShaderMask), findsNothing);
+        update(() => stopped = false);
+        await tester.pump();
+        await tester.pump(const Duration(milliseconds: 100));
+        expect(tester.binding.hasScheduledFrame, isTrue);
+        expect(find.byType(ShaderMask), findsOneWidget);
+        await tester.pumpWidget(const SizedBox.shrink());
+        expect(tester.takeException(), isNull);
+      },
+    );
+  }
+
+  testWidgets('reduced motion shows list content immediately', (tester) async {
+    await tester.pumpWidget(
+      const MaterialApp(
+        home: MediaQuery(
+          data: MediaQueryData(disableAnimations: true),
+          child: StaggeredListItem(index: 8, child: Text('Album')),
+        ),
+      ),
+    );
+    expect(find.text('Album').hitTestable(), findsOneWidget);
+    expect(find.byType(TweenAnimationBuilder<double>), findsNothing);
+    await tester.pump(const Duration(seconds: 1));
+    expect(tester.binding.hasScheduledFrame, isFalse);
+  });
+}