import 'package:flutter/material.dart'; Future?> buildSnackbar(BuildContext context, String message, {int durationSec = 3}) async { if (!context.mounted) { return null; } final snackBar = SnackBar( content: SelectableText(message), duration: Duration(seconds: durationSec), showCloseIcon: true, ); return ScaffoldMessenger.of(context).showSnackBar(snackBar); }