flutter snackbar
final snackBar = SnackBar( content: Text('Yay! A SnackBar!'), action: SnackBarAction( label: 'Undo', onPressed: () { // Some code to undo the change. }, ), ); // Find the Scaffold in the widget tree and use // it to show a SnackBar. Scaffold.of(context).showSnackBar(snackBar);