Show feedback and status

Use an alert for status that belongs in the content, a snackbar for transient feedback, and a banner for a message near the top of the application.

Render an inline alert

This alert stays in the widget tree until your application removes it:

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

  @override
  Widget build(BuildContext context) => const DievasAlert(
    title: 'Changes could not be saved',
    description: 'Check your connection and try again.',
    tone: DievasAlertTone.error,
    variant: DievasAlertVariant.outlined,
  );
}

title is required. tone defaults to info; other tones are success, warning, and error. variant defaults to filled, with base and outlined alternatives.

Use label or content to supply custom title/body widgets. A custom leading takes precedence over leadingIcon. If you supply both onTrailingTap and onDismiss, the trailing callback takes precedence.

Show a transient snackbar

Use the nearest scope controller so the snackbar mounts in the correct overlay:

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

  @override
  Widget build(BuildContext context) => DievasFilledButton(
    label: 'Show saved feedback',
    onPressed: () => DievasScope.of(context).showSnackbar(
      (context, animation) => const DievasSnackbar(message: 'Changes saved'),
    ),
  );
}

The default snackbar timeout is 4 seconds. showBanner defaults to 5 seconds. Pass duration: Duration.zero to keep either visible until you call hideSnackbar() or hideBanner(). Showing another message replaces the active message in that scope slot and restarts the countdown.

A DievasBanner requires tone and message. Its onDismiss callback should hide the scope-owned banner. A DievasSnackbarAction provides a labelled callback for actions such as Undo; your application must implement the actual undo operation.

Customise and verify

Use the alert and snackbar component theme entries. Keep tone and copy aligned; an error must not rely on colour alone. Verify message announcement and visibility duration with the assistive technology your application supports. Critical information should remain available in the content rather than disappearing only in a snackbar.

Explore and inspect

Select Alert, Banner, or Snackbar in the interactive gallery. See the alert API and scope controller API.