🐛 DatePicker throws Exception: A RenderListWheelViewport was mutated in _RenderLayoutBuilder.performLayout.

[pamtbaau]

Describe the bug A clear and concise description of what the bug is.

When changing the value of a DatePicker by scrolling the date, an exception is thrown when setState() is called in onChanged.

Workaround until fixed: Wrap setState() inside a Future.delayed():

      onChanged: (value) {
        Future.delayed(const Duration(milliseconds: 500), () {
          setState(() {
            selected = value;
          });
        });
      },

To Reproduce Steps to reproduce the behavior:

• Create fresh Flutter app using cli
• Add the following dependency:

  fluent_ui:
  git: https://github.com/bdlukaa/fluent_ui.git

• Update main.dart as follows:

  import 'package:fluent_ui/fluent_ui.dart';
  
  void main() async {
  runApp(const MyApp());
  }
  
  class MyApp extends StatelessWidget {
  const MyApp({super.key});
  
  @override
  Widget build(BuildContext context) {
    return FluentApp(
      title: 'Bug issue',
      home: NavigationView(
        pane: NavigationPane(
          selected: 0,
          displayMode: PaneDisplayMode.compact,
          items: [
            PaneItem(
              icon: const Icon(FluentIcons.home),
              title: const Text('Home'),
              body: Container(
                alignment: Alignment.center,
                child: const DateWidget(),
              ),
            ),
          ],
        ),
      ),
    );
  }
  }
  
  class DateWidget extends StatefulWidget {
  const DateWidget({super.key});
  
  @override
  State<DateWidget> createState() => DateWidgetState();
  }
  
  class DateWidgetState extends State<DateWidget> {
  DateTime selected = DateTime.now();
  
  @override
  void initState() {
    super.initState();
  }
  
  @override
  Widget build(BuildContext context) {
    return DatePicker(
      selected: selected,
      fieldOrder: const [
        DatePickerField.year,
        DatePickerField.month,
        DatePickerField.day,
      ],
      onChanged: (value) {
        setState(() {
          selected = value;
        });
      },
    );
  }
  }

• Run app in debug mode
  • Change date by scrolling the year, month or day value.
  • Error is thrown.
• Run app in release mode
  • Change date by scrolling the year, month or day value.
  • All goes well.

Expected behavior A clear and concise description of what you expected to happen.

Screenshots If applicable, add screenshots to help explain your problem.

Additional context Add any other context about the problem here.

[bdlukaa]

We are calling onChanged before popping the picker. I believe changing this order fixes this issue.

[MiaraSystems]

I see the same issue.