无法分配“RequestRetrier”类型的值？键入“RequestRetrier？”答案

【问题标题】：Cannot assign value of type 'RequestRetrier?' to type 'RequestRetrier?'无法分配“RequestRetrier”类型的值？键入“RequestRetrier？”
【发布时间】：2018-06-08 01:01:16
【问题描述】：

我正在尝试像 Alamofire 页面中的示例一样使请求重试器，但我收到此错误：

这里是请求重试代码：

public typealias RequestRetryCompletion = (_ shouldRetry: Bool, _ timeDelay: TimeInterval) -> Void

public protocol RequestRetrier {
func should(_ manager: SessionManager, retry request: Request, with error: Error, completion: @escaping RequestRetryCompletion)}

class RequestRetryHandler: RequestRetrier {
public func should(_ manager: SessionManager, retry request: Request, with error: Error, completion: @escaping RequestRetryCompletion) {
    if let response = request.task?.response as? HTTPURLResponse, response.statusCode == 503 {
        completion(true, 10.0) // retry after 1 second

    } else {
        completion(false, 0.0) // don't retry
    }
}}

这就是错误发生的地方：

let manager = Alamofire.SessionManager.default
manager.retrier = RequestRetryHandler() as? RequestRetrier

【问题讨论】：

标签： ios swift networking alamofire

【解决方案1】：

您不应该重新声明协议或RequestRetryCompletion。这已经在 Alamofire 中为您完成了。您需要做的就是：

import Alamofire
import Foundation

class RequestRetryHandler: RequestRetrier {
    func should(_ manager: SessionManager, retry request: Request, with error: Error, completion: @escaping RequestRetryCompletion) {
        if let response = request.task?.response as? HTTPURLResponse, response.statusCode == 503 {
            completion(true, 10.0) // retry after 1 second

        } else {
            completion(false, 0.0) // don't retry
        }
    }
}

let manager = Alamofire.SessionManager.default
manager.retrier = RequestRetryHandler()

祝你好运！

【讨论】：