[Bug report] 如何兼容 ExtendedNestedScrollView、NestedScrollView

[hkm5558]

Version

1.26.3

Platforms

dart

Device Model

iPhone 12 Pro Max iOS 26.2.1

flutter info

[✓] Flutter (Channel stable, 3.38.7, on macOS 26.2 25C56 darwin-arm64, locale zh-Hans-CN)
[✓] Android toolchain - develop for Android devices (Android SDK version 36.0.0)
[✓] Xcode - develop for iOS and macOS (Xcode 26.2)
[✓] Network resources

• No issues found!

How to reproduce?

如何兼容 extended_nested_scroll_view、nested_scroll_view

0x0 List.single (dart:core)
0x0 ScrollController.position + 173 (scroll_controller.dart:173)
0x0 ObserverControllerForScroll._scrollToIndex + 451 (observer_controller.dart:451)

final scrollController = PrimaryScrollController.of(context);
observerController.controller = scrollController;

布局为 ExtendedNestedScrollView + TabBarView + ListView/GridView，TabBarView 每切到一个新 tab，scrollController 的 positions 数量便会+1，
而此时去触发滚动到对应下标， 451 行 final pixels = _controller.position.pixels.rectify(obj); 这句会抛出异常。

[LinXunFeng]

已添加相应示例

• 在线预览: flutter_scrollview_observer/#/nested_scroll_view_tab_bar_view
• 代码: nested_scrollview_tab_bar_view_demo