Use CustomScrollView

lib/components/thumbnail_gridview.dart

@@ -0,0 +1,25 @@
+import 'package:flutter/material.dart';
+import '../api/file.dart';
+import '../api/gallery.dart';
+import 'thumbnail.dart';
+
+class ThumbnailGridView extends StatelessWidget {
+  const ThumbnailGridView(this.pages, this.gridDelegate, {Key? key, this.files})
+      : super(key: key);
+  final List<ExtendedPMeta> pages;
+  final EhFiles? files;
+  final SliverGridDelegate gridDelegate;
+
+  @override
+  Widget build(BuildContext context) {
+    return SliverGrid.builder(
+        gridDelegate: gridDelegate,
+        itemCount: pages.length,
+        itemBuilder: (context, index) {
+          final page = pages[index]!;
+          final fileId =
+              files != null ? files!.files[page.token]!.first.id : null;
+          return Thumbnail(page, fileId: fileId);
+        });
+  }
+}