Why sometimes snackbar is failing
Try to check if the widget is still mounted in the three:
void showFailedSnackBar(String s) { if (mounted) { SnackBar snackBar = SnackBar( content: Text(s), duration: Duration(seconds: 3), backgroundColor: Theme.of(context).primaryColor, ); ScaffoldMessenger.of(context).showSnackBar(snackBar); } }
In your function showSnackbar, besides the String you could also pass a BuildContext context variable, so you know which context you pass e.g.
SnackBar snackBar = SnackBar( content: Text(s), duration: Duration(seconds: 3), backgroundColor: Theme.of(context).primaryColor, ); ScaffoldMessenger.of(context).showSnackBar(snackBar); }You could save the context of the scaffold that you are sure it exists in a provider in order to pass it around where you need it.