swift - 尝试在 Swift 中将泛型类型作为参数传递

Question

我正在使用 AlamofireObjectMapper 我需要制作一个带有通用参数的函数:

func doSomething < T : BaseMappable > (myCustomClass : T) 
{
    Alamofire.request("url", method: .get, parameters: nil, encoding: JSONEncoding.default, headers: APIKeys().AuthorizedHeader).responseObject(completionHandler: { ( response :DataResponse<T>) in

             let data = response.result.value

            if let array = data?.objects
            {
                for ar in array
                {
                   self.allPromotions.append(ar)
                }
            }

        })


}

但我收到错误:

Use of undeclared type 'myCustomClass' edit as you guys answer me in the comments i put fixed the error but i got another error when iam trying to call this method

我是这样调用方法的

doSomething(myCustomClass: Promotions)

但是我得到了另一个错误

Argument type 'Promotions.Type' does not conform to expected type 'BaseMappable'

这是我的促销类(class)

import ObjectMapper


class Promotions : Mappable  {





        var id:Int?
        var workshop_id:Int?
        var title:String?
        var desc:String?
        var start_date:String?
        var expire_date:String?
        var type:String?

        var objects  = [Promotions]()




        required init?(map: Map){

        }

        func mapping(map: Map) {
            id <- map["id"]
            workshop_id <- map["workshop_id"]
            title <- map["title"]
            desc <- map["desc"]
            start_date <- map["start_date"]
            expire_date <- map["expire_date"]
            type <- map["type"]
            objects <- map["promotions"]
        }




}

我该如何解决

Answer 1

您需要将通用类型 T 的类型作为参数传递。尝试更改

myCustomClass : T

由

myCustomClass : T.Type

结果如下:

swift 4:

    func doSomething<T>(myCustomClass : T.Type) where T : BaseMappable
    {
        Alamofire.request("url", method: .get, parameters: nil, encoding: JSONEncoding.default, headers: APIKeys().AuthorizedHeader).responseObject(completionHandler: { ( response :DataResponse<T>) in

                 let data = response.result.value

                if let array = data?.objects
                {
                    for ar in array
                    {
                       self.allPromotions.append(ar)
                    }
                }

            })
    }

然后，您应该调用方法:

doSomething(myCustomClass: Promotions.self)