无法转换Promise(

本文介绍了无法转换Promise(_，_)->类型的返回表达式返回类型Promise< DataResponse，AnyObject>>的DataRequest.的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！ 问题描述

无法将Promise(，)类型的返回表达式转换为DataRequest以返回Promise>类型的

我的功能是

func postJson(_ url: String, parameters: [String: String]) -> Promise<DataResponse<AnyObject>> { var request = URLRequest(url: URL(string: url)!) request.httpMethod = "POST" request.setValue("application/json", forHTTPHeaderField: "Content-Type") request.httpBody = try! JSONSerialization.data(withJSONObject: parameters) return Promise { fulfill, reject in manager.request(request) .responseJSON { response in fulfill(response) }

然后在Promise返回行中收到此错误.如何转换?

我尝试将返回签名更改为Promise<DataRequest, Error，并在该行上看到编译错误，因为Promise过于专门化了2个参数而不是1个参数.

解决方案

fulfill存在问题，因为它需要参数DataResponse<AnyObject>，但是您正在传递DataResponse<Any>.

将postJson方法的返回类型更改为Promise<DataResponse<Any>>应该可以解决您的问题.

更改此行

func postJson(_ url: String, parameters: [String: String]) -> Promise<DataResponse<AnyObject>> {

到

func postJson(_ url: String, parameters: [String: String]) -> Promise<DataResponse<Any>> {

Cannot convert return expression of type Promise (,) -> DataRequest to return type Promise>

my function is

func postJson(_ url: String, parameters: [String: String]) -> Promise<DataResponse<AnyObject>> { var request = URLRequest(url: URL(string: url)!) request.httpMethod = "POST" request.setValue("application/json", forHTTPHeaderField: "Content-Type") request.httpBody = try! JSONSerialization.data(withJSONObject: parameters) return Promise { fulfill, reject in manager.request(request) .responseJSON { response in fulfill(response) }

And I get this error on the return Promise line. How do I convert ?

I tried changing my return signature to Promise<DataRequest, Error and get a compile error on that line that Promise is too specialized with 2 parameters instead of 1.

解决方案

Problem is with fulfill because it's expecting parameter DataResponse<AnyObject> but you are passing DataResponse<Any>.

Changing return type of your postJson method to Promise<DataResponse<Any>> should solve your problem.

Change this line

func postJson(_ url: String, parameters: [String: String]) -> Promise<DataResponse<AnyObject>> {

to

func postJson(_ url: String, parameters: [String: String]) -> Promise<DataResponse<Any>> {