name: Flutter UI Widgets description: Principles for maintainable UI components. metadata: labels: [ui, widgets] triggers: files: ['_page.dart', '_screen.dart', '/widgets/'] keywords: [StatelessWidget, const, Theme, ListView]

UI & Widgets

Priority: P1 (OPERATIONAL)

Standards for building reusable, performant Flutter widgets and UI components.

• State: Use StatelessWidget by default. StatefulWidget only for local state/controllers.
• Composition: Extract UI into small, atomic const widgets.
• Theming: Use Theme.of(context). No hardcoded colors.
• Layout: Use Flex + Gap/SizedBox.
• Specialized:
  • SelectionArea: For multi-widget text selection.
  • InteractiveViewer: For zoom/pan.
  • ListWheelScrollView: For pickers.
  • IntrinsicWidth/Height: Avoid unless strictly required.
• Large Lists: Always use ListView.builder.

class AppButton extends StatelessWidget {
  final String label;
  final VoidCallback onPressed;
  const AppButton({super.key, required this.label, required this.onPressed});

  @override
  Widget build(BuildContext context) => ElevatedButton(onPressed: onPressed, child: Text(label));
}

Related Topics

performance | testing