validate method
Implementation
@override
String? validate(String? value, bool required, Map<String, dynamic> data) {
if (value != null) {
if (!required && value.isEmpty) {
return null;
}
if (exact != null && value.length != exact!) {
return short
? "Need $exact characters"
: "Need exact $exact characters";
}
if (min != null && value.length < min!) {
return short ? "Need $min characters" : "Longer than $min characters";
}
if (max != null && value.length > max!) {
return short ? "Only $max characters" : "Lesser than $max characters";
}
}
return null;
}