keep stack children alive

Author: mertalev

mobile/lib/presentation/widgets/asset_viewer/asset_viewer.page.dart

@@ -116,6 +116,8 @@ class _AssetViewerState extends ConsumerState<AssetViewer> {
   ImageStream? _prevPreCacheStream;
   ImageStream? _nextPreCacheStream;
 
+  KeepAliveLink? _stackChildrenKeepAlive;
+
   @override
   void initState() {
     super.initState();
@@ -126,6 +128,10 @@ class _AssetViewerState extends ConsumerState<AssetViewer> {
     WidgetsBinding.instance.addPostFrameCallback(_onAssetInit);
     reloadSubscription = EventStream.shared.listen(_onEvent);
     heroOffset = widget.heroOffset ?? TabsRouterScope.of(context)?.controller.activeIndex ?? 0;
+    final asset = ref.read(currentAssetNotifier);
+    if (asset != null) {
+      _stackChildrenKeepAlive = ref.read(stackChildrenNotifier(asset).notifier).ref.keepAlive();
+    }
   }
 
   @override
@@ -137,6 +143,7 @@ class _AssetViewerState extends ConsumerState<AssetViewer> {
     _prevPreCacheStream?.removeListener(_dummyListener);
     _nextPreCacheStream?.removeListener(_dummyListener);
     SystemChrome.setEnabledSystemUIMode(SystemUiMode.edgeToEdge);
+    _stackChildrenKeepAlive?.close();
     super.dispose();
   }
 
@@ -200,6 +207,8 @@ class _AssetViewerState extends ConsumerState<AssetViewer> {
     widget.changeAsset(ref, asset);
     _precacheAssets(index);
     _handleCasting();
+    _stackChildrenKeepAlive?.close();
+    _stackChildrenKeepAlive = ref.read(stackChildrenNotifier(asset).notifier).ref.keepAlive();
   }
 
   void _handleCasting() {
@@ -527,7 +536,7 @@ class _AssetViewerState extends ConsumerState<AssetViewer> {
     BaseAsset displayAsset = asset;
     final stackChildren = ref.read(stackChildrenNotifier(asset)).valueOrNull;
     if (stackChildren != null && stackChildren.isNotEmpty) {
-      displayAsset = stackChildren.elementAt(ref.read(assetViewerProvider.select((s) => s.stackIndex)));
+      displayAsset = stackChildren.elementAt(ref.read(assetViewerProvider).stackIndex);
     }
 
     final isPlayingMotionVideo = ref.read(isPlayingMotionVideoProvider);