swift - 使用枚举登录

Question

我正在尝试创建一种简单的用户登录方式，但目前它似乎不起作用。我不断收到错误消息，并在 .Email(LoginUser)

中缺少参数

enum LoginProvider {
    case Facebook
    case Email(String, String)

    func login() {
        switch self {
        case .Email(LoginUser) where LoginUser.isValid():
            break

        case .Facebook:

            break
        }
    }

}

struct LoginUser {
    let email: String
    let password: String
    func isValid() -> Bool {
        return email != "" && password != ""
    }

}

Answer 1

你在代码中犯了一些错误，这是修复后的版本:

enum LoginProvider {
    case Facebook
    case Email(LoginUser) // note that LoginUser is used as Type here

    func login() {
        switch self {

        // And here, loginUser is an instance of type LoginUser
        case .Email(let loginUser) where loginUser.isValid():
            break

        case .Email(let loginUser):
            // Switch has to be exhaustive, 
            // in this case you should handle invalid user
            break

        case .Facebook:
            break
        }
    }

}

struct LoginUser {
    let email: String
    let password: String
    func isValid() -> Bool {
        return !email.isEmpty && !password.isEmpty
    }
}

我还建议您查看 Apple's Swift book 中有关关联值的章节.