uDoubleValidator static method
uDoubleValidator returns null if the given doubleString
is valid.
Implementation
static String? uDoubleValidator(String? doubleString) {
if (doubleString == null || doubleString.isEmpty) {
return ("Cannot be empty");
}
if (!RegExp(r'^[0-9]+.?[0-9]*$').hasMatch(doubleString) &&
(doubleString).isNotEmpty) {
return ("Only a positive number is allowed");
}
return (null);
}