validatePhone static method

Implementation

static String? validatePhone(String? val) {
  if (val!.isEmpty) {
    return 'Phone number is empty';
  } else if (val.length > 16 || val.length < 9) {
    return 'Phone number is not valid';
  }
  if (RegExp(r'^[+]*[(]{0,1}[0-9]{1,4}[)]{0,1}[-\s\./0-9]*$').hasMatch(val)) {
    return null;
  } else {
    return 'Phone number is not valid';
  }
}