error-handling - 天气应用程序中的 ErrorType 协议(protocol)

Question

我对 Swift 很陌生，正在尝试创建天气应用程序。我有协议(protocol) func weatherManagerFailedToLoadCityWithError(error: ErrorType) .在 weatherManager.swift 中有一些委托(delegate)

} else if status == 404 {
                // City not found
                if self.delegate != nil {
                    dispatch_async(dispatch_get_main_queue(), { () -> Void in
                        self.delegate?.weatherManagerFailerToLoadCityWithError(.InvalidResponse)
                    })
                }

            } else {
                // Some other here?
                if self.delegate != nil {
                    dispatch_async(dispatch_get_main_queue(), { () -> Void in
                        self.delegate?.weatherManagerFailerToLoadCityWithError(.MissingData)
                    })
                }
            }

在这个代码块中我应该怎么做weatherController.swift

func weatherManagerFailedToLoadCityWithError(error: ErrorType) {

}

有什么建议吗？

Answer 1

你可以这样做:

private struct ErrorInformation {
    static let Domain = "us.firmaName"
    static let ServerNotFoundDomain = "\(ErrorInformation.Domain).notFound"
}

private extension NSError {
    static func serverNotFound() -> NSError {
       let userInfo = [
           NSLocalizedDescriptionKey: NSLocalizedString("Server Not Found", comment: ""),
           NSLocalizedFailureReasonErrorKey: NSLocalizedString("The Server you are asking for is not available.", comment: ""),
           NSLocalizedRecoverySuggestionErrorKey: NSLocalizedString("Please proof your URL bla-bla-bla.", comment: "")
       ]

    return NSError(domain: ErrorInformation.ServerNotFoundDomain, code: 404, userInfo: userInfo)
}

然后调用你的函数:

weatherManagerFailedToLoadCityWithError(error: NSError.serverNotFound())

如果你愿意，你可以在你的函数中处理错误:

func weatherManagerFailedToLoadCityWithError(error: ErrorType) {
   print("Error description: \(error.userInfo. NSLocalizedDescriptionKey)")
}

如果您需要更多解释，只需发布​​更多代码。