GridView/SliverGrid infinity scroll when [builder] returns null and itemCount is not used #130685
Description
Is there an existing issue for this?
- I have searched the existing issues
- I have read the guide to filing a bug
Steps to reproduce
- Run the sample.
- Scroll to the end of the grid view.
Expected results
The GridView should end when itemCount is not explicitly determined and the builder returns null at some point. This is necessary when you need a builder to create the elements on-demand. It works fine with ListView (included at the code sample).
As per API docs, if itemCount is null, the number of children is determined by the least index for which [builder] returns null.
Actual results
The GridView keep scrolling to infinite and sometimes bounce to the top of the list after some scrolling.
I suspect this behavior is occurring due to estimateMaxScrollOffset return infinite when childCount is null:
Code sample
Code sample
import 'package:flutter/material.dart';
void main() => runApp(MyApp());
class MyApp extends StatelessWidget {
@override
Widget build(BuildContext context) {
return MaterialApp(
title: 'Flutter Demo',
debugShowCheckedModeBanner: false,
theme: ThemeData(
primarySwatch: Colors.blue,
),
home: const MyHomePage(title: 'Flutter Demo Home Page'),
);
}
}
class MyHomePage extends StatefulWidget {
final String title;
const MyHomePage({
Key? key,
required this.title,
}) : super(key: key);
@override
State<MyHomePage> createState() => _MyHomePageState();
}
class _MyHomePageState extends State<MyHomePage> {
@override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
title: Text(widget.title),
),
body: GridView.builder(
gridDelegate: const SliverGridDelegateWithFixedCrossAxisCount(
crossAxisCount: 3,
crossAxisSpacing: 16,
mainAxisSpacing: 16,
),
itemBuilder: (context, index) {
if (index == 12) return null;
return Container(
height: 100,
width: 100,
color: Colors.orange,
alignment: Alignment.center,
child: Text('item ${index+1}'),
);
},
),
/*
// Using ListView works fine:
body: ListView.builder(
itemBuilder: (context, index) {
if (index == 12) return null;
return Container(
height: 100,
width: 100,
color: Colors.orange,
alignment: Alignment.center,
child: Text('item ${index+1}'),
);
},
),
*/
);
}
}Flutter Doctor output
Doctor output
[✓] Flutter (Channel stable, 3.10.5, on macOS 13.4.1 22F82 darwin-arm64, locale en-EG)
• Flutter version 3.10.5 on channel stable at /Users/bx777/development/sdks/flutter
• Upstream repository https://github.com/flutter/flutter.git
• Framework revision 796c8ef792 (5 weeks ago), 2023-06-13 15:51:02 -0700
• Engine revision 45f6e00911
• Dart version 3.0.5
• DevTools version 2.23.1
[✓] Android toolchain - develop for Android devices (Android SDK version 33.0.0)
• Android SDK at /Users/bx777/Library/Android/sdk
• Platform android-33, build-tools 33.0.0
• Java binary at: /Applications/Android Studio.app/Contents/jbr/Contents/Home/bin/java
• Java version OpenJDK Runtime Environment (build 11.0.15+0-b2043.56-8887301)
• All Android licenses accepted.
[✓] Xcode - develop for iOS and macOS (Xcode 14.3.1)
• Xcode at /Applications/Xcode.app/Contents/Developer
• Build 14E300c
• CocoaPods version 1.12.1
[✓] Chrome - develop for the web
• Chrome at /Applications/Google Chrome.app/Contents/MacOS/Google Chrome
[✓] Android Studio (version 2022.1)
• Android Studio at /Applications/Android Studio.app/Contents
• Flutter plugin can be installed from:
🔨 https://plugins.jetbrains.com/plugin/9212-flutter
• Dart plugin can be installed from:
🔨 https://plugins.jetbrains.com/plugin/6351-dart
• Java version OpenJDK Runtime Environment (build 11.0.15+0-b2043.56-8887301)
[✓] VS Code (version 1.80.1)
• VS Code at /Applications/Visual Studio Code.app/Contents
• Flutter extension version 3.68.0
[✓] Connected device (3 available)
• sdk gphone64 arm64 (mobile) • emulator-5554 • android-arm64 • Android 13 (API 33) (emulator)
• macOS (desktop) • macos • darwin-arm64 • macOS 13.4.1 22F82 darwin-arm64
• Chrome (web) • chrome • web-javascript • Google Chrome 114.0.5735.198
[✓] Network resources
• All expected network resources are available.
• No issues found!Metadata
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Important issues not at the top of the work listViewports, list views, slivers, etc.Found to occur in 3.10Found to occur in 3.13flutter/packages/flutter repository. See also f: labels.The issue has been confirmed reproducible and is ready to work onIssue is closed as already fixed in a newer versionOwned by Framework teamTriaged by Framework team