斯威夫特结果是未使用

Question

我无法弄清楚如何在swift3去除这样的警告：

调用“responseMessagesArray”的结果没有被使用

这是我的代码看起来像：

fileprivate class func getMessagesAtPath(_ path: String, tokenKey: String, completionHandler: @escaping (MyMessagesWrapper?, NSError?) -> Void) { 
     let credentialData = ":\(tokenKey)".data(using: String.Encoding.utf8)! 
     let base64Credentials = credentialData.base64EncodedString(options: []) 

     let headers = ["Accept": "application/json", 
         "Content-Type": "application/json", 
         "Authorization": "Basic \(base64Credentials)"] 

     Alamofire.request(path, headers: headers) 
      .responseMessagesArray { response in 
       if let error = response.result.error 
       { 
        completionHandler(nil, error as NSError?) 
        return 
       } 
       completionHandler(response.result.value, nil) 
     } 
    } 

    class func getMyMessages(_ completionHandler: @escaping (MyMessagesWrapper?, NSError?) -> Void) { 
     getMessagesAtPath(MyMessages.endpointForMyMessages(),tokenKey: MyMessages.getTokenKey(),completionHandler: completionHandler) 
    } 

extension Alamofire.DataRequest { 
    func responseMessagesArray(_ completionHandler: @escaping (DataResponse<MyMessagesWrapper>) -> Void) -> Self { 
     let responseSerializer = DataResponseSerializer<MyMessagesWrapper> { request, response, data, error in 
      guard error == nil else 
      { 
       return .failure(error!) 
      } 
      guard let responseData = data else { 
       return .failure(AFError.responseSerializationFailed(reason: .inputDataNil)) 

      } 

      let JSONResponseSerializer = DataRequest.jsonResponseSerializer(options: .allowFragments) 
      let result = JSONResponseSerializer.serializeResponse(request, response, responseData, error) 

      switch result { 
      case .success(let value): 
       let json = JSON(value) 
       let wrapper = MyMessagesWrapper() 

       wrapper.next = json["messages"]["next_page_url"].stringValue 
       wrapper.previous = json["messages"]["prev_page_url"].stringValue 
       wrapper.count = json["messages"]["total"].intValue 

       var allMessages:Array = Array<MyMessages>() 
       print(json) 
       let results = json["messages"]["data"] 
       //print(results) 
       for jsonAds in results 
       { 
        //print(jsonAds.1) 
        let mesaggesData = MyMessages(json: jsonAds.1, id: Int(jsonAds.0)) 
        allMessages.append(mesaggesData) 
       } 
       wrapper.myMessages = allMessages 
       return .success(wrapper) 
      case .failure(let error): 
       return .failure(error) 
      } 
     } 

     return response(responseSerializer: responseSerializer, 
         completionHandler: completionHandler) 
    } 
} 

我从fileprivate类FUNC getMessagesAtPath（）警告 流向何方.responseMessagesArray {响应在出现

我从未有过迅速2.

Answer 1

此警告该函数的返回值赋给_明确地丢弃它，就像这样：

_ = somethingThatReturnsAValueYouDontCareAbout() 

斯威夫特3警告有关未使用函数返回值，所以你需要显示它，你知道你在做什么。