据我了解，默认情况下，Alamofire 请求在后台线程中运行。

当我尝试运行这段代码时:

let productsEndPoint: String = "http://api.test.com/Products?username=testuser"

        Alamofire.request(productsEndPoint, method: .get)
            .responseJSON { response in
                // check for errors
                guard response.result.error == nil else {
                    // got an error in getting the data, need to handle it
                    print("Inside error guard")
                    print(response.result.error!)
                    return
                }

                // make sure we got some JSON since that's what we expect
                guard let json = response.result.value as? [String: Any] else {
                    print("didn't get products as JSON from API")
                    print("Error: \(response.result.error)")
                    return
                }

                // get and print the title
                guard let products = json["products"] as? [[String: Any]] else {
                    print("Could not get products from JSON")
                    return
                }
                print(products)

        }

在网络调用的所有项目完成打印之前，UI 没有响应；所以我尝试将 GCD 与 Alamofire 一起使用:

let queue = DispatchQueue(label: "com.test.api", qos: .background, attributes: .concurrent)

    queue.async {

        let productsEndPoint: String = "http://api.test.com/Products?username=testuser"

        Alamofire.request(productsEndPoint, method: .get)
            .responseJSON { response in
                // check for errors
                guard response.result.error == nil else {
                    // got an error in getting the data, need to handle it
                    print("Inside error guard")
                    print(response.result.error!)
                    return
                }

                // make sure we got some JSON since that's what we expect
                guard let json = response.result.value as? [String: Any] else {
                    print("didn't get products as JSON from API")
                    print("Error: \(response.result.error)")
                    return
                }

                // get and print the title
                guard let products = json["products"] as? [[String: Any]] else {
                    print("Could not get products from JSON")
                    return
                }
                print(products)

        }
    }

而且 UI 仍然像以前一样没有响应。

我是不是做错了什么，还是 Alamofire 出了问题？

最佳答案

我对默认情况下在后台线程上运行的 Alamofire 的看法是错误的。它实际上默认在主队列上运行。我在 Alamofire 的 Github 页面上打开了一个问题，它已经在这里解决了:https://github.com/Alamofire/Alamofire/issues/1922

解决我的问题的正确方法是使用 .responseJSON 方法上的“queue”参数指定我希望运行请求的队列类型 (

.responseJSON(queue: queue) { response in
...
}

)

这是我的代码的完整、更正版本:

let productsEndPoint: String = "http://api.test.com/Products?username=testuser"

    let queue = DispatchQueue(label: "com.test.api", qos: .background, attributes: .concurrent)

    Alamofire.request(productsEndPoint, method: .get)
        .responseJSON(queue: queue) { response in
            // check for errors
            guard response.result.error == nil else {
                // got an error in getting the data, need to handle it
                print("Inside error guard")
                print(response.result.error!)
                return
            }

            // make sure we got some JSON since that's what we expect
            guard let json = response.result.value as? [String: Any] else {
                print("didn't get products as JSON from API")
                print("Error: \(response.result.error)")
                return
            }

            // get and print the title
            guard let products = json["products"] as? [[String: Any]] else {
                print("Could not get products from JSON")
                return
            }
            print(products)
     }

关于ios - Alamofire 网络调用未在后台线程中运行，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/41725511/