refactor(library): move queue download labels, dialogs and sliver grid out of queue_tab.dart

Pure moves: download label helpers and the download dialogs become parts of
the queue_tab library, and the animated sliver grid becomes a public widget
in lib/widgets since it uses no private state.

lib/screens/queue_tab.dart

@@ -84,6 +84,7 @@ import 'package:spotiflac_android/screens/queue_library_refresh_policy.dart';
 import 'package:spotiflac_android/utils/clickable_metadata.dart';
 import 'package:spotiflac_android/utils/string_utils.dart';
 import 'package:spotiflac_android/widgets/download_service_picker.dart';
+import 'package:spotiflac_android/widgets/animated_library_sliver_grid.dart';
 import 'package:spotiflac_android/widgets/animation_utils.dart';
 import 'package:spotiflac_android/widgets/selection_bottom_bar.dart';
 import 'package:spotiflac_android/widgets/smoothed_progress.dart';
@@ -99,110 +100,8 @@ part 'queue_tab_filter_widgets.dart';
 part 'queue_tab_sections.dart';
 part 'queue_tab_batch_actions.dart';
 part 'queue_tab_item_widgets.dart';
-
-String _formatDownloadSizeMB(num bytes) => '${formatMegabytes(bytes)} MB';
-
-String _formatDownloadProgressLabel(
-  BuildContext context,
-  DownloadItem item, {
-  double? visualProgress,
-}) {
-  final progress = (visualProgress ?? item.progress).clamp(0.0, 1.0);
-  final speedSuffix = item.speedMBps > 0
-      ? ' • ${item.speedMBps.toStringAsFixed(1)} MB/s'
-      : '';
-
-  if (item.bytesTotal > 0) {
-    final received = visualProgress != null
-        ? item.bytesTotal * progress
-        : item.bytesReceived > 0
-        ? item.bytesReceived
-        : item.bytesTotal * progress;
-    final percent = (progress * 100).toStringAsFixed(0);
-    return '${_formatDownloadSizeMB(received)} / ${_formatDownloadSizeMB(item.bytesTotal)} • $percent%$speedSuffix';
-  }
-
-  if (item.bytesReceived > 0) {
-    final canEstimateTotal = progress > 0.01 && progress < 0.995;
-    if (canEstimateTotal) {
-      final estimatedTotal = item.bytesReceived / progress;
-      if (estimatedTotal > item.bytesReceived) {
-        return '${_formatDownloadSizeMB(item.bytesReceived)} / ~${_formatDownloadSizeMB(estimatedTotal)}$speedSuffix';
-      }
-    }
-    return '${_formatDownloadSizeMB(item.bytesReceived)}$speedSuffix';
-  }
-
-  if (progress > 0) {
-    final percent = (progress * 100).toStringAsFixed(0);
-    return '$percent%$speedSuffix';
-  }
-
-  if (item.speedMBps > 0) {
-    return context.l10n.queueDownloadSpeedStatus(
-      item.speedMBps.toStringAsFixed(1),
-    );
-  }
-
-  if (item.error == 'Waiting for verification') {
-    return context.l10n.queueWaitingForVerification;
-  }
-  switch (item.preparationStage) {
-    case 'checking_session':
-      return context.l10n.queueCheckingDownloadSession;
-    case 'resolving_metadata':
-      return context.l10n.queueResolvingDownloadMetadata;
-    case 'resolving_stream':
-      return context.l10n.queueResolvingDownloadStream;
-  }
-  if (item.error == 'Retrying after verification') {
-    return context.l10n.queueResumingAfterVerification;
-  }
-
-  return context.l10n.queueDownloadStarting;
-}
-
-String _formatDownloadStatusLine(
-  BuildContext context,
-  DownloadItem item, {
-  double? visualProgress,
-}) {
-  final base = _formatDownloadProgressLabel(
-    context,
-    item,
-    visualProgress: visualProgress,
-  );
-  final eta = _formatDownloadEta(item, visualProgress: visualProgress);
-  return eta == null ? base : '$base • $eta';
-}
-
-String? _formatDownloadEta(DownloadItem item, {double? visualProgress}) {
-  if (item.speedMBps <= 0 || item.bytesTotal <= 0) return null;
-  final progress = (visualProgress ?? item.progress).clamp(0.0, 1.0);
-  final received = visualProgress != null
-      ? (item.bytesTotal * progress).round()
-      : item.bytesReceived > 0
-      ? item.bytesReceived
-      : (item.bytesTotal * progress).round();
-  final remaining = item.bytesTotal - received;
-  if (remaining <= 0) return null;
-  final seconds = remaining / (item.speedMBps * 1024 * 1024);
-  if (!seconds.isFinite || seconds > 3600) return null;
-  if (seconds < 60) return '~${seconds.round()}s';
-  final minutes = (seconds / 60).floor();
-  final secs = (seconds % 60).round();
-  return '~${minutes}m${secs.toString().padLeft(2, '0')}s';
-}
-
-bool _shouldAnimateDownloadProgress(BuildContext context, DownloadItem item) {
-  final progress = item.progress.clamp(0.0, 1.0);
-  final animationsDisabled =
-      MediaQuery.maybeDisableAnimationsOf(context) ?? false;
-  return item.status == DownloadStatus.downloading &&
-      progress > 0 &&
-      progress < 1 &&
-      !animationsDisabled;
-}
+part 'queue_tab_download_labels.dart';
+part 'queue_tab_download_dialogs.dart';
 
 DownloadHistoryItem? _historyItemForCompletionBridge(
   DownloadItem item,
@@ -1848,254 +1747,4 @@ class _QueueTabState extends ConsumerState<QueueTab> {
       },
     );
   }
-
-  Future<void> _confirmCancelDownload(
-    BuildContext context,
-    DownloadItem item,
-  ) async {
-    final confirmed = await showAppDialog<bool>(
-      context: context,
-      builder: (ctx) => AppAlertDialog(
-        title: Text(context.l10n.cancelDownloadTitle),
-        content: Text(context.l10n.cancelDownloadContent(item.track.name)),
-        actions: [
-          AppDialogAction(
-            onPressed: () => Navigator.of(ctx).pop(false),
-            child: Text(context.l10n.cancelDownloadKeep),
-          ),
-          AppDialogAction(
-            isDestructive: true,
-            onPressed: () => Navigator.of(ctx).pop(true),
-            child: Text(context.l10n.dialogCancel),
-          ),
-        ],
-      ),
-    );
-    if (confirmed == true) {
-      // cancelItem (not dismissItem): the item stays in the queue as
-      // cancelled so it can be retried without re-searching the track.
-      ref.read(downloadQueueProvider.notifier).cancelItem(item.id);
-    }
-  }
-
-  Future<void> _showDownloadErrorDialog(
-    BuildContext context,
-    DownloadItem item,
-  ) async {
-    final colorScheme = Theme.of(context).colorScheme;
-    final isRateLimit = item.errorType == DownloadErrorType.rateLimit;
-    final isCancelled = item.status == DownloadStatus.skipped;
-    final isFolderAccessLost =
-        item.errorMessage == safPermissionLostErrorMessage ||
-        item.errorMessage == downloadFolderAccessLostErrorMessage;
-    final title = isCancelled
-        ? context.l10n.queueCancelledTitle
-        : isRateLimit
-        ? context.l10n.queueRateLimitTitle
-        : context.l10n.updateDownloadFailed;
-    final message = isCancelled
-        ? context.l10n.queueCancelledMessage
-        : isRateLimit
-        ? context.l10n.queueRateLimitMessage
-        : (item.errorMessage.trim().isNotEmpty
-              ? _localizedDownloadError(context, item.errorMessage)
-              : context.l10n.updateDownloadFailed);
-    final action = await showAppDialog<String>(
-      context: context,
-      builder: (ctx) => AppAlertDialog(
-        title: Text(title),
-        content: SingleChildScrollView(
-          child: Column(
-            crossAxisAlignment: CrossAxisAlignment.start,
-            mainAxisSize: MainAxisSize.min,
-            children: [
-              Text(
-                item.track.name,
-                style: Theme.of(
-                  ctx,
-                ).textTheme.titleSmall?.copyWith(fontWeight: FontWeight.w600),
-              ),
-              const SizedBox(height: 10),
-              SelectableText(
-                message,
-                style: Theme.of(ctx).textTheme.bodyMedium,
-              ),
-            ],
-          ),
-        ),
-        actions: [
-          AppDialogAction(
-            isDestructive: true,
-            onPressed: () => Navigator.of(ctx).pop('remove'),
-            style: TextButton.styleFrom(foregroundColor: colorScheme.error),
-            child: Text(context.l10n.dialogRemove),
-          ),
-          AppDialogAction(
-            onPressed: () => Navigator.of(ctx).pop(),
-            child: Text(context.l10n.dialogCancel),
-          ),
-          if (isFolderAccessLost)
-            AppDialogAction(
-              filled: true,
-              onPressed: () => Navigator.of(ctx).pop('reselect'),
-              child: Text(context.l10n.downloadFolderReselect),
-            )
-          else
-            AppDialogAction(
-              filled: true,
-              onPressed: () => Navigator.of(ctx).pop('retry'),
-              child: Text(context.l10n.dialogRetry),
-            ),
-        ],
-      ),
-    );
-    if (!mounted) return;
-    if (action == 'retry') {
-      ref.read(downloadQueueProvider.notifier).retryItem(item.id);
-    } else if (action == 'remove') {
-      ref.read(downloadQueueProvider.notifier).removeItem(item.id);
-    } else if (action == 'reselect') {
-      final reselected = await _reselectDownloadFolder();
-      if (reselected && mounted) {
-        ref.read(downloadQueueProvider.notifier).retryItem(item.id);
-      }
-    }
-  }
-
-  /// Reopen the platform folder picker to restore download folder access,
-  /// then persist the new location. Returns true when a folder was saved.
-  Future<bool> _reselectDownloadFolder() async {
-    if (Platform.isAndroid) {
-      final result = await PlatformBridge.pickSafTree();
-      if (result == null) return false;
-      final treeUri = result['tree_uri'] as String? ?? '';
-      final displayName = result['display_name'] as String? ?? '';
-      if (treeUri.isEmpty) return false;
-      final notifier = ref.read(settingsProvider.notifier);
-      notifier.setStorageMode('saf');
-      notifier.setDownloadTreeUri(
-        treeUri,
-        displayName: displayName.isNotEmpty ? displayName : treeUri,
-      );
-      return true;
-    }
-    if (Platform.isIOS) {
-      IosPickedDirectory? picked;
-      try {
-        picked = await PlatformBridge.pickIosDirectory();
-      } catch (e) {
-        if (mounted) {
-          ScaffoldMessenger.of(context).showSnackBar(
-            SnackBar(
-              content: Text(
-                context.l10n.snackbarFolderPickerFailed(
-                  context.friendlyError(e),
-                ),
-              ),
-            ),
-          );
-        }
-        return false;
-      }
-      if (picked == null || !mounted) return false;
-      final validation = validateIosPath(
-        picked.path,
-        bookmark: picked.bookmark,
-      );
-      if (!validation.isValid) {
-        if (mounted) {
-          ScaffoldMessenger.of(context).showSnackBar(
-            SnackBar(
-              content: Text(
-                validation.errorReason ?? context.l10n.setupIcloudNotSupported,
-              ),
-            ),
-          );
-        }
-        return false;
-      }
-      ref
-          .read(settingsProvider.notifier)
-          .setDownloadDirectory(picked.path, iosBookmark: picked.bookmark);
-      return true;
-    }
-    return false;
-  }
-}
-
-class _AnimatedLibrarySliverGrid extends StatefulWidget {
-  final double maxCrossAxisExtent;
-  final double mainAxisSpacing;
-  final double crossAxisSpacing;
-  final double childAspectRatio;
-  final SliverChildDelegate delegate;
-
-  const _AnimatedLibrarySliverGrid({
-    required this.maxCrossAxisExtent,
-    required this.mainAxisSpacing,
-    required this.crossAxisSpacing,
-    required this.childAspectRatio,
-    required this.delegate,
-  });
-
-  @override
-  State<_AnimatedLibrarySliverGrid> createState() =>
-      _AnimatedLibrarySliverGridState();
-}
-
-class _AnimatedLibrarySliverGridState extends State<_AnimatedLibrarySliverGrid>
-    with SingleTickerProviderStateMixin {
-  late final AnimationController _controller;
-  late final CurvedAnimation _curve;
-  late double _beginExtent;
-  late double _endExtent;
-
-  @override
-  void initState() {
-    super.initState();
-    _beginExtent = widget.maxCrossAxisExtent;
-    _endExtent = widget.maxCrossAxisExtent;
-    _controller = AnimationController(
-      vsync: this,
-      duration: const Duration(milliseconds: 130),
-    )..value = 1;
-    _curve = CurvedAnimation(parent: _controller, curve: Curves.easeOutCubic);
-  }
-
-  @override
-  void didUpdateWidget(covariant _AnimatedLibrarySliverGrid oldWidget) {
-    super.didUpdateWidget(oldWidget);
-    if ((widget.maxCrossAxisExtent - _endExtent).abs() < 0.1) return;
-    _beginExtent = _currentExtent;
-    _endExtent = widget.maxCrossAxisExtent;
-    _controller.forward(from: 0);
-  }
-
-  double get _currentExtent =>
-      _beginExtent + ((_endExtent - _beginExtent) * _curve.value);
-
-  @override
-  void dispose() {
-    _curve.dispose();
-    _controller.dispose();
-    super.dispose();
-  }
-
-  @override
-  Widget build(BuildContext context) {
-    return AnimatedBuilder(
-      animation: _controller,
-      builder: (context, child) {
-        return SliverGrid(
-          gridDelegate: SliverGridDelegateWithMaxCrossAxisExtent(
-            maxCrossAxisExtent: _currentExtent,
-            mainAxisSpacing: widget.mainAxisSpacing,
-            crossAxisSpacing: widget.crossAxisSpacing,
-            childAspectRatio: widget.childAspectRatio,
-          ),
-          delegate: widget.delegate,
-        );
-      },
-    );
-  }
 }

lib/screens/queue_tab_download_dialogs.dart

@@ -0,0 +1,176 @@
+part of 'queue_tab.dart';
+
+extension _QueueTabDownloadDialogs on _QueueTabState {
+  Future<void> _confirmCancelDownload(
+    BuildContext context,
+    DownloadItem item,
+  ) async {
+    final confirmed = await showAppDialog<bool>(
+      context: context,
+      builder: (ctx) => AppAlertDialog(
+        title: Text(context.l10n.cancelDownloadTitle),
+        content: Text(context.l10n.cancelDownloadContent(item.track.name)),
+        actions: [
+          AppDialogAction(
+            onPressed: () => Navigator.of(ctx).pop(false),
+            child: Text(context.l10n.cancelDownloadKeep),
+          ),
+          AppDialogAction(
+            isDestructive: true,
+            onPressed: () => Navigator.of(ctx).pop(true),
+            child: Text(context.l10n.dialogCancel),
+          ),
+        ],
+      ),
+    );
+    if (confirmed == true) {
+      // cancelItem (not dismissItem): the item stays in the queue as
+      // cancelled so it can be retried without re-searching the track.
+      ref.read(downloadQueueProvider.notifier).cancelItem(item.id);
+    }
+  }
+
+  Future<void> _showDownloadErrorDialog(
+    BuildContext context,
+    DownloadItem item,
+  ) async {
+    final colorScheme = Theme.of(context).colorScheme;
+    final isRateLimit = item.errorType == DownloadErrorType.rateLimit;
+    final isCancelled = item.status == DownloadStatus.skipped;
+    final isFolderAccessLost =
+        item.errorMessage == safPermissionLostErrorMessage ||
+        item.errorMessage == downloadFolderAccessLostErrorMessage;
+    final title = isCancelled
+        ? context.l10n.queueCancelledTitle
+        : isRateLimit
+        ? context.l10n.queueRateLimitTitle
+        : context.l10n.updateDownloadFailed;
+    final message = isCancelled
+        ? context.l10n.queueCancelledMessage
+        : isRateLimit
+        ? context.l10n.queueRateLimitMessage
+        : (item.errorMessage.trim().isNotEmpty
+              ? _localizedDownloadError(context, item.errorMessage)
+              : context.l10n.updateDownloadFailed);
+    final action = await showAppDialog<String>(
+      context: context,
+      builder: (ctx) => AppAlertDialog(
+        title: Text(title),
+        content: SingleChildScrollView(
+          child: Column(
+            crossAxisAlignment: CrossAxisAlignment.start,
+            mainAxisSize: MainAxisSize.min,
+            children: [
+              Text(
+                item.track.name,
+                style: Theme.of(
+                  ctx,
+                ).textTheme.titleSmall?.copyWith(fontWeight: FontWeight.w600),
+              ),
+              const SizedBox(height: 10),
+              SelectableText(
+                message,
+                style: Theme.of(ctx).textTheme.bodyMedium,
+              ),
+            ],
+          ),
+        ),
+        actions: [
+          AppDialogAction(
+            isDestructive: true,
+            onPressed: () => Navigator.of(ctx).pop('remove'),
+            style: TextButton.styleFrom(foregroundColor: colorScheme.error),
+            child: Text(context.l10n.dialogRemove),
+          ),
+          AppDialogAction(
+            onPressed: () => Navigator.of(ctx).pop(),
+            child: Text(context.l10n.dialogCancel),
+          ),
+          if (isFolderAccessLost)
+            AppDialogAction(
+              filled: true,
+              onPressed: () => Navigator.of(ctx).pop('reselect'),
+              child: Text(context.l10n.downloadFolderReselect),
+            )
+          else
+            AppDialogAction(
+              filled: true,
+              onPressed: () => Navigator.of(ctx).pop('retry'),
+              child: Text(context.l10n.dialogRetry),
+            ),
+        ],
+      ),
+    );
+    if (!mounted) return;
+    if (action == 'retry') {
+      ref.read(downloadQueueProvider.notifier).retryItem(item.id);
+    } else if (action == 'remove') {
+      ref.read(downloadQueueProvider.notifier).removeItem(item.id);
+    } else if (action == 'reselect') {
+      final reselected = await _reselectDownloadFolder();
+      if (reselected && mounted) {
+        ref.read(downloadQueueProvider.notifier).retryItem(item.id);
+      }
+    }
+  }
+
+  /// Reopen the platform folder picker to restore download folder access,
+  /// then persist the new location. Returns true when a folder was saved.
+  Future<bool> _reselectDownloadFolder() async {
+    if (Platform.isAndroid) {
+      final result = await PlatformBridge.pickSafTree();
+      if (result == null) return false;
+      final treeUri = result['tree_uri'] as String? ?? '';
+      final displayName = result['display_name'] as String? ?? '';
+      if (treeUri.isEmpty) return false;
+      final notifier = ref.read(settingsProvider.notifier);
+      notifier.setStorageMode('saf');
+      notifier.setDownloadTreeUri(
+        treeUri,
+        displayName: displayName.isNotEmpty ? displayName : treeUri,
+      );
+      return true;
+    }
+    if (Platform.isIOS) {
+      IosPickedDirectory? picked;
+      try {
+        picked = await PlatformBridge.pickIosDirectory();
+      } catch (e) {
+        if (mounted) {
+          ScaffoldMessenger.of(context).showSnackBar(
+            SnackBar(
+              content: Text(
+                context.l10n.snackbarFolderPickerFailed(
+                  context.friendlyError(e),
+                ),
+              ),
+            ),
+          );
+        }
+        return false;
+      }
+      if (picked == null || !mounted) return false;
+      final validation = validateIosPath(
+        picked.path,
+        bookmark: picked.bookmark,
+      );
+      if (!validation.isValid) {
+        if (mounted) {
+          ScaffoldMessenger.of(context).showSnackBar(
+            SnackBar(
+              content: Text(
+                validation.errorReason ?? context.l10n.setupIcloudNotSupported,
+              ),
+            ),
+          );
+        }
+        return false;
+      }
+      ref
+          .read(settingsProvider.notifier)
+          .setDownloadDirectory(picked.path, iosBookmark: picked.bookmark);
+      return true;
+    }
+    return false;
+  }
+}

lib/screens/queue_tab_download_labels.dart

@@ -0,0 +1,105 @@
+part of 'queue_tab.dart';
+
+String _formatDownloadSizeMB(num bytes) => '${formatMegabytes(bytes)} MB';
+
+String _formatDownloadProgressLabel(
+  BuildContext context,
+  DownloadItem item, {
+  double? visualProgress,
+}) {
+  final progress = (visualProgress ?? item.progress).clamp(0.0, 1.0);
+  final speedSuffix = item.speedMBps > 0
+      ? ' • ${item.speedMBps.toStringAsFixed(1)} MB/s'
+      : '';
+
+  if (item.bytesTotal > 0) {
+    final received = visualProgress != null
+        ? item.bytesTotal * progress
+        : item.bytesReceived > 0
+        ? item.bytesReceived
+        : item.bytesTotal * progress;
+    final percent = (progress * 100).toStringAsFixed(0);
+    return '${_formatDownloadSizeMB(received)} / ${_formatDownloadSizeMB(item.bytesTotal)} • $percent%$speedSuffix';
+  }
+
+  if (item.bytesReceived > 0) {
+    final canEstimateTotal = progress > 0.01 && progress < 0.995;
+    if (canEstimateTotal) {
+      final estimatedTotal = item.bytesReceived / progress;
+      if (estimatedTotal > item.bytesReceived) {
+        return '${_formatDownloadSizeMB(item.bytesReceived)} / ~${_formatDownloadSizeMB(estimatedTotal)}$speedSuffix';
+      }
+    }
+    return '${_formatDownloadSizeMB(item.bytesReceived)}$speedSuffix';
+  }
+
+  if (progress > 0) {
+    final percent = (progress * 100).toStringAsFixed(0);
+    return '$percent%$speedSuffix';
+  }
+
+  if (item.speedMBps > 0) {
+    return context.l10n.queueDownloadSpeedStatus(
+      item.speedMBps.toStringAsFixed(1),
+    );
+  }
+
+  if (item.error == 'Waiting for verification') {
+    return context.l10n.queueWaitingForVerification;
+  }
+  switch (item.preparationStage) {
+    case 'checking_session':
+      return context.l10n.queueCheckingDownloadSession;
+    case 'resolving_metadata':
+      return context.l10n.queueResolvingDownloadMetadata;
+    case 'resolving_stream':
+      return context.l10n.queueResolvingDownloadStream;
+  }
+  if (item.error == 'Retrying after verification') {
+    return context.l10n.queueResumingAfterVerification;
+  }
+
+  return context.l10n.queueDownloadStarting;
+}
+
+String _formatDownloadStatusLine(
+  BuildContext context,
+  DownloadItem item, {
+  double? visualProgress,
+}) {
+  final base = _formatDownloadProgressLabel(
+    context,
+    item,
+    visualProgress: visualProgress,
+  );
+  final eta = _formatDownloadEta(item, visualProgress: visualProgress);
+  return eta == null ? base : '$base • $eta';
+}
+
+String? _formatDownloadEta(DownloadItem item, {double? visualProgress}) {
+  if (item.speedMBps <= 0 || item.bytesTotal <= 0) return null;
+  final progress = (visualProgress ?? item.progress).clamp(0.0, 1.0);
+  final received = visualProgress != null
+      ? (item.bytesTotal * progress).round()
+      : item.bytesReceived > 0
+      ? item.bytesReceived
+      : (item.bytesTotal * progress).round();
+  final remaining = item.bytesTotal - received;
+  if (remaining <= 0) return null;
+  final seconds = remaining / (item.speedMBps * 1024 * 1024);
+  if (!seconds.isFinite || seconds > 3600) return null;
+  if (seconds < 60) return '~${seconds.round()}s';
+  final minutes = (seconds / 60).floor();
+  final secs = (seconds % 60).round();
+  return '~${minutes}m${secs.toString().padLeft(2, '0')}s';
+}
+
+bool _shouldAnimateDownloadProgress(BuildContext context, DownloadItem item) {
+  final progress = item.progress.clamp(0.0, 1.0);
+  final animationsDisabled =
+      MediaQuery.maybeDisableAnimationsOf(context) ?? false;
+  return item.status == DownloadStatus.downloading &&
+      progress > 0 &&
+      progress < 1 &&
+      !animationsDisabled;
+}

lib/screens/queue_tab_filter_widgets.dart

@@ -466,7 +466,7 @@ extension _QueueTabFilterWidgets on _QueueTabState {
                 filteredGroupedLocalAlbums.isNotEmpty))
           SliverPadding(
             padding: EdgeInsets.symmetric(horizontal: edge),
-            sliver: _AnimatedLibrarySliverGrid(
+            sliver: AnimatedLibrarySliverGrid(
               maxCrossAxisExtent: _libraryAlbumGridExtent,
               mainAxisSpacing: 12,
               crossAxisSpacing: 12,
@@ -521,7 +521,7 @@ extension _QueueTabFilterWidgets on _QueueTabState {
           ),
           SliverPadding(
             padding: EdgeInsets.symmetric(horizontal: edge),
-            sliver: _AnimatedLibrarySliverGrid(
+            sliver: AnimatedLibrarySliverGrid(
               maxCrossAxisExtent: _libraryAlbumGridExtent,
               mainAxisSpacing: 12,
               crossAxisSpacing: 12,
@@ -562,7 +562,7 @@ extension _QueueTabFilterWidgets on _QueueTabState {
           if (historyViewMode == 'grid')
             SliverPadding(
               padding: EdgeInsets.symmetric(horizontal: edge),
-              sliver: _AnimatedLibrarySliverGrid(
+              sliver: AnimatedLibrarySliverGrid(
                 maxCrossAxisExtent: _libraryGridExtent,
                 mainAxisSpacing: 8,
                 crossAxisSpacing: 8,
@@ -746,7 +746,7 @@ extension _QueueTabFilterWidgets on _QueueTabState {
           historyViewMode == 'grid'
               ? SliverPadding(
                   padding: EdgeInsets.symmetric(horizontal: edge),
-                  sliver: _AnimatedLibrarySliverGrid(
+                  sliver: AnimatedLibrarySliverGrid(
                     maxCrossAxisExtent: _libraryGridExtent,
                     mainAxisSpacing: 8,
                     crossAxisSpacing: 8,

lib/widgets/animated_library_sliver_grid.dart

@@ -0,0 +1,79 @@
+import 'package:flutter/material.dart';
+
+class AnimatedLibrarySliverGrid extends StatefulWidget {
+  final double maxCrossAxisExtent;
+  final double mainAxisSpacing;
+  final double crossAxisSpacing;
+  final double childAspectRatio;
+  final SliverChildDelegate delegate;
+
+  const AnimatedLibrarySliverGrid({
+    super.key,
+    required this.maxCrossAxisExtent,
+    required this.mainAxisSpacing,
+    required this.crossAxisSpacing,
+    required this.childAspectRatio,
+    required this.delegate,
+  });
+
+  @override
+  State<AnimatedLibrarySliverGrid> createState() =>
+      _AnimatedLibrarySliverGridState();
+}
+
+class _AnimatedLibrarySliverGridState extends State<AnimatedLibrarySliverGrid>
+    with SingleTickerProviderStateMixin {
+  late final AnimationController _controller;
+  late final CurvedAnimation _curve;
+  late double _beginExtent;
+  late double _endExtent;
+
+  @override
+  void initState() {
+    super.initState();
+    _beginExtent = widget.maxCrossAxisExtent;
+    _endExtent = widget.maxCrossAxisExtent;
+    _controller = AnimationController(
+      vsync: this,
+      duration: const Duration(milliseconds: 130),
+    )..value = 1;
+    _curve = CurvedAnimation(parent: _controller, curve: Curves.easeOutCubic);
+  }
+
+  @override
+  void didUpdateWidget(covariant AnimatedLibrarySliverGrid oldWidget) {
+    super.didUpdateWidget(oldWidget);
+    if ((widget.maxCrossAxisExtent - _endExtent).abs() < 0.1) return;
+    _beginExtent = _currentExtent;
+    _endExtent = widget.maxCrossAxisExtent;
+    _controller.forward(from: 0);
+  }
+
+  double get _currentExtent =>
+      _beginExtent + ((_endExtent - _beginExtent) * _curve.value);
+
+  @override
+  void dispose() {
+    _curve.dispose();
+    _controller.dispose();
+    super.dispose();
+  }
+
+  @override
+  Widget build(BuildContext context) {
+    return AnimatedBuilder(
+      animation: _controller,
+      builder: (context, child) {
+        return SliverGrid(
+          gridDelegate: SliverGridDelegateWithMaxCrossAxisExtent(
+            maxCrossAxisExtent: _currentExtent,
+            mainAxisSpacing: widget.mainAxisSpacing,
+            crossAxisSpacing: widget.crossAxisSpacing,
+            childAspectRatio: widget.childAspectRatio,
+          ),
+          delegate: widget.delegate,
+        );
+      },
+    );
+  }
+}