[Bug report] GridView长度发生变化后，无法jumpTo新增的item

[qwqwqw213]

Version

1.27.0

Platforms

iOS, Android

Device Model

readme(Android 10)

flutter info

[√] Flutter (Channel stable, 3.44.6, on Microsoft Windows [版本 10.0.26200.9168], locale zh-CN) [473ms]
    • Flutter version 3.44.6 on channel stable at D:\lib\flutter
    • Upstream repository https://github.com/flutter/flutter.git
    • Framework revision ee80f08bbf (6 weeks ago), 2026-07-08 15:02:06 -0700
    • Engine revision 83675ed276
    • Dart version 3.12.2
    • DevTools version 2.57.0
    • Pub download mirror https://pub.flutter-io.cn
    • Flutter download mirror https://storage.flutter-io.cn
    • Feature flags: enable-web, enable-linux-desktop, enable-macos-desktop, enable-windows-desktop, enable-android, enable-ios, cli-animations, enable-native-assets, enable-swift-package-manager,
      omit-legacy-version-file, enable-lldb-debugging, enable-uiscene-migration

[√] Windows Version (11 Home China 64-bit, 25H2, 2009) [1,647ms]

[√] Android toolchain - develop for Android devices (Android SDK version 37.0.0) [3.3s]
    • Android SDK at D:\lib\android_kid\sdk
    • Emulator version 36.6.11.0 (build_id 15507667) (CL:N/A)
    • Platform android-37.0, build-tools 37.0.0
    • ANDROID_HOME = D:\lib\android_kid\sdk
    • Java binary at: D:\tool\AndroidStudio\jbr\bin\java
      This is the JDK bundled with the latest Android Studio installation on this machine.
      To manually set the JDK path, use: `flutter config --jdk-dir="path/to/jdk"`.
    • Java version OpenJDK Runtime Environment (build 17.0.11+0--11852314)
    • All Android licenses accepted.

[X] Chrome - develop for the web (Cannot find Chrome executable at .\Google\Chrome\Application\chrome.exe) [184ms]
    ! Cannot find Chrome. Try setting CHROME_EXECUTABLE to a Chrome executable.

[√] Visual Studio - develop Windows apps (Visual Studio 生成工具 2026 18.7.0) [182ms]
    • Visual Studio at D:\lib\msvc_2022
    • Visual Studio 生成工具 2026 version 18.7.11903.348
    • Windows 10 SDK version 10.0.26100.0

[√] Connected device (3 available) [395ms]
    • Redmi Note 7 Pro (mobile) • 1d67d46e • android-arm64  • Android 10 (API 29)
    • Windows (desktop)         • windows  • windows-x64    • Microsoft Windows [版本 10.0.26200.9168]
    • Edge (web)                • edge     • web-javascript • Microsoft Edge 151.0.4129.86

How to reproduce?

在DEMO中
一开始点击add后list会新增并setState重绘，再点击jump进行跳转
无法跳转到新增item
第二次点击jump则可以跳转
我认为这是grid没有加载非可视区域item导致的（list新增后_scrollCtrl.position.maxScrollExtent未发生变化）

Logs

Example code (optional)

import 'package:flutter/material.dart';
import 'package:flutter/services.dart';
import 'package:scrollview_observer/scrollview_observer.dart';

void main() async {
  WidgetsFlutterBinding.ensureInitialized();
  await SystemChrome.setPreferredOrientations([
    DeviceOrientation.landscapeLeft,
    DeviceOrientation.landscapeRight,
  ]);
  runApp(const MyApp());
}

class MyApp extends StatelessWidget {
  const MyApp({super.key});

  // This widget is the root of your application.
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Flutter Demo',
      theme: ThemeData(
        colorScheme: .fromSeed(seedColor: Colors.deepPurple),
      ),
      home: const MyHomePage(),
    );
  }
}

class MyHomePage extends StatefulWidget {
  const MyHomePage({super.key});

  @override
  State<MyHomePage> createState() => _MyHomePageState();
}

class _MyHomePageState extends State<MyHomePage> {
  final List<Color> _list = [];

  final ScrollController _scrollCtrl = ScrollController();

  late GridObserverController _observerCtrl;

  void _add() {
    final List<Color> list = [
      Colors.red,
      Colors.green,
      Colors.blue,
      Colors.yellow,
    ];
    for(int i = 0; i < 5; i ++) {
      _list.addAll(list);
    }

    setState(() {
      
    });
  }

  void _jump() {
    _observerCtrl.jumpTo(
      index: _list.length - 1,
      isFixedHeight: true,
    );
  }

  @override
  void initState() {
    super.initState();

    _observerCtrl = GridObserverController(controller: _scrollCtrl);

    _add();
  }

  @override
  Widget build(BuildContext context) {
    final crossCount = 4;
    final crossSpacing = 5.0;
    final Size screen = MediaQuery.of(context).size;

    final double cellWidth = (screen.width - (crossCount - 1) * crossSpacing) / crossCount;

    debugPrint("list length: ${_list.length} cellSize: $cellWidth");

    return Scaffold(
      appBar: AppBar(
        backgroundColor: Theme.of(context).colorScheme.inversePrimary,
        title: Text("Observer grid"),
        actions: [
          const SizedBox(width: 10),
          TextButton(onPressed: _add, child: const Text("1st add")), // first click
          const SizedBox(width: 10),
          TextButton(onPressed: _jump, child: const Text("2nd jump")), // second click
          const SizedBox(width: 10),
        ],
      ),
      body: Center(
        child: GridViewObserver(
          controller: _observerCtrl,
          child: GridView.custom(
            controller: _scrollCtrl,
            gridDelegate: SliverGridDelegateWithFixedCrossAxisCount(
              crossAxisCount: crossCount,
              mainAxisSpacing: crossSpacing,
              crossAxisSpacing: crossSpacing,
              mainAxisExtent: cellWidth,
            ),
            childrenDelegate: SliverChildBuilderDelegate(
              (ctx, index) {
                return Container(
                  color: _list[index],
                  child: Center(
                    child: Text(
                      (index + 1).toString(),
                      style: const TextStyle(color: Colors.black, fontSize: 22),
                    ),
                  ),
                );
              },
              childCount: _list.length,
            ),
          ),
        ),
      ),
    );
  }
}

Contact

382805749@qq.com

[LinXunFeng]

更新使用 1.27.1 版本