ios - 使用自定义消息处理错误？

Question

如何使用自定义消息抛出错误消息(即 ErrorType)？

例如:

catch let error as MyError {
  print(error.customMessage)
}

Answer 1

我找到了这个干净的版本。这个想法是同时实现 String 和 ErrorType 协议(protocol)并使用错误的 rawValue。

enum UserValidationError: String, ErrorType {
  case NoFirstNameProvided = "Please insert your first name."
  case NoLastNameProvided = "Please insert your last name."
  case NoAgeProvided = "Please insert your age."
  case NoEmailProvided = "Please insert your email."
}

用法:

do {
  try User.define(firstName,
                  lastName: lastName,
                  age: age,
                  email: email,
                  gender: gender,
                  location: location,
                  phone: phone)
}
catch let error as User.UserValidationError {
  print(error.rawValue)
  return
}