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CupertinoPicker should report item change only on scroll end #170201
Description
This is a continuation of #169606
Steps to reproduce
Scroll the picker over multiple items.
Expected results
Native picker only reports the change when the scroll settles.
Actual results
onSelectedItemChanged is called every time a new item is scrolled over.
Code sample
Code sample
import 'package:flutter/cupertino.dart';
/// Flutter code sample for [CupertinoPicker].
const double _kItemExtent = 32.0;
const List<String> _fruitNames = <String>[
'Apple',
'Mango',
'Banana',
'Orange',
'Pineapple',
'Strawberry',
];
void main() => runApp(const CupertinoPickerApp());
class CupertinoPickerApp extends StatelessWidget {
const CupertinoPickerApp({super.key});
@override
Widget build(BuildContext context) {
return const CupertinoApp(
theme: CupertinoThemeData(brightness: Brightness.light),
home: CupertinoPickerExample(),
);
}
}
class CupertinoPickerExample extends StatefulWidget {
const CupertinoPickerExample({super.key});
@override
State<CupertinoPickerExample> createState() => _CupertinoPickerExampleState();
}
class _CupertinoPickerExampleState extends State<CupertinoPickerExample> {
int _selectedFruit = 0;
// This shows a CupertinoModalPopup with a reasonable fixed height which hosts CupertinoPicker.
void _showDialog(Widget child) {
showCupertinoModalPopup<void>(
context: context,
builder:
(BuildContext context) => Container(
height: 216,
padding: const EdgeInsets.only(top: 6.0),
// The Bottom margin is provided to align the popup above the system navigation bar.
margin: EdgeInsets.only(bottom: MediaQuery.of(context).viewInsets.bottom),
// Provide a background color for the popup.
color: CupertinoColors.systemBackground.resolveFrom(context),
// Use a SafeArea widget to avoid system overlaps.
child: SafeArea(top: false, child: child),
),
);
}
@override
Widget build(BuildContext context) {
return CupertinoPageScaffold(
navigationBar: const CupertinoNavigationBar(middle: Text('CupertinoPicker Sample')),
child: DefaultTextStyle(
style: TextStyle(color: CupertinoColors.label.resolveFrom(context), fontSize: 22.0),
child: Center(
child: Row(
mainAxisAlignment: MainAxisAlignment.center,
children: <Widget>[
const Text('Selected fruit: '),
CupertinoButton(
padding: EdgeInsets.zero,
// Display a CupertinoPicker with list of fruits.
onPressed:
() => _showDialog(
CupertinoPicker(
magnification: 1.22,
squeeze: 1.2,
useMagnifier: true,
itemExtent: _kItemExtent,
// This sets the initial item.
scrollController: FixedExtentScrollController(initialItem: _selectedFruit),
// This is called when selected item is changed.
onSelectedItemChanged: (int selectedItem) {
setState(() {
_selectedFruit = selectedItem;
});
},
children: List<Widget>.generate(_fruitNames.length, (int index) {
return Center(child: Text(_fruitNames[index]));
}),
),
),
// This displays the selected fruit name.
child: Text(_fruitNames[_selectedFruit], style: const TextStyle(fontSize: 22.0)),
),
],
),
),
),
);
}
}Screenshots or Video
Screenshots / Video demonstration
[Upload media here]
Logs
Logs
[Paste your logs here]Flutter Doctor output
Doctor output
[!] Flutter (Channel [user-branch], 3.33.0-1.0.pre.417, on macOS 15.5 24F74 darwin-arm64, locale en-GB) [8.3s]
! Flutter version 3.33.0-1.0.pre.417 on channel [user-branch] at /Users/alex/workspace/flutter_fork
Currently on an unknown channel. Run `flutter channel` to switch to an official channel.
If that doesn't fix the issue, reinstall Flutter by following instructions at https://flutter.dev/setup.
! Upstream repository https://github.com/flutter/flutter.git/ is not a standard remote.
Set environment variable "FLUTTER_GIT_URL" to https://github.com/flutter/flutter.git/ to dismiss this error.
• Framework revision e9e989bef3 (5 hours ago), 2025-06-07 07:45:31 -0400
• Engine revision e9e989bef3
• Dart version 3.9.0 (build 3.9.0-211.0.dev)
• DevTools version 2.48.0-dev.0
• If those were intentional, you can disregard the above warnings; however it is recommended to use "git" directly to perform update checks and
upgrades.
[✓] Android toolchain - develop for Android devices (Android SDK version 35.0.0) [2.1s]
• Android SDK at /Users/alex/Library/Android/sdk
• Emulator version 35.2.10.0 (build_id 12414864) (CL:N/A)
• Platform android-36, build-tools 35.0.0
• ANDROID_HOME = /Users/alex/Library/Android/sdk
• Java binary at: /Applications/Android Studio.app/Contents/jbr/Contents/Home/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 21.0.3+-79915917-b509.11)
• All Android licenses accepted.
[!] Xcode - develop for iOS and macOS (Xcode 16.4) [1,360ms]
• Xcode at /Applications/Xcode.app/Contents/Developer
• Build 16F6
! CocoaPods 1.13.0 out of date (1.16.2 is recommended).
CocoaPods is a package manager for iOS or macOS platform code.
Without CocoaPods, plugins will not work on iOS or macOS.
For more info, see https://flutter.dev/to/platform-plugins
To update CocoaPods, see https://guides.cocoapods.org/using/getting-started.html#updating-cocoapods
[✗] Chrome - develop for the web (Cannot find Chrome executable at /Applications/Google Chrome.app/Contents/MacOS/Google Chrome) [13ms]
! Cannot find Chrome. Try setting CHROME_EXECUTABLE to a Chrome executable.
[✓] Android Studio (version 2024.2) [12ms]
• 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 21.0.3+-79915917-b509.11)
[✓] VS Code (version 1.100.3) [10ms]
• VS Code at /Applications/Visual Studio Code.app/Contents
• Flutter extension version 3.112.0
[✓] Connected device (3 available) [7.0s]
• Alex’s iPhone (wireless) (mobile) • 00008130-001A310C0491401C • ios • iOS 18.5 22F76
• iPhone 16 Pro (mobile) • CA350618-1F12-428B-ABB3-9D688B09D1F4 • ios • com.apple.CoreSimulator.SimRuntime.iOS-18-5 (simulator)
• macOS (desktop) • macos • darwin-arm64 • macOS 15.5 24F74 darwin-arm64
[✓] Network resources [856ms]
• All expected network resources are available.
! Doctor found issues in 3 categories.
Activity
danagbemava-nc commentedon Jun 9, 2025
Reproducible (as noted in the #169606).
flutter doctor -v
`CupertinoPicker` new onChanged behaviour (#170202)
github-actions commentedon Jul 2, 2025
This thread has been automatically locked since there has not been any recent activity after it was closed. If you are still experiencing a similar issue, please open a new bug, including the output of
flutter doctor -vand a minimal reproduction of the issue.`CupertinoPicker` new onChanged behaviour (flutter#170202)
`CupertinoPicker` new onChanged behaviour (#170202)
`CupertinoPicker` new onChanged behaviour (#170202)