Question

有人能帮助我吗？我找不到完成语法的好例子。

var url : NSURL = NSURL.URLWithString("https://itunes.apple.com/search?term=\(searchTerm)&media=software")
var request: NSURLRequest = NSURLRequest(URL:url)
let config = NSURLSessionConfiguration.defaultSessionConfiguration()
let session = NSURLSession.sessionWithConfiguration(config)

NSURLSessionDataTask(session.dataTaskWithRequest(request, completionHandler: ((NSData!, NSURLResponse!, NSError!) -> Void)?)

谢谢！

Answer 1

不清楚你在问什么，但我注意到你的代码中有一些错误：

您应该使用session

NSURLSession(configuration: config)

session.dataTaskWithRequest返回NSURLSessionDataTask，因此无需将其包含在NSURLSessionDataTask()内（也称为实例化新的NSURLSessionDataTask对象）。
< / LI>

完成处理程序是一个闭包，下面是你如何创建特定的clousure：

{(data : NSData!, response : NSURLResponse!, error : NSError!) in

    // your code

}

这是更新后的代码：

let url = NSURL(string: "https://itunes.apple.com/search?term=\(searchTerm)&media=software")
let request = NSURLRequest(URL: url)
let config = NSURLSessionConfiguration.defaultSessionConfiguration()
let session = NSURLSession(configuration: config)

let task = session.dataTaskWithRequest(request, completionHandler: {(data, response, error) in

    // notice that I can omit the types of data, response and error

    // your code

});

// do whatever you need with the task e.g. run
task.resume()

Answer 2

如果您在完成语法方面遇到问题，可以在调用dataTaskWithRequest（..）之前创建完成函数以使其更清晰

func handler (data: NSData!, response: NSURLResponse!, error: NSError!) {
            //handle what you need
        }

session.dataTaskWithRequest(request, completionHandler: handler)

Answer 3

您也可以通过以下方式使用它： -

let url = "api url"

let nsURL = NSURL

let task = NSURLSession.sharedSession().dataTaskWithURL(nsURL) {
(data, response, error) in
   // your condition on success and failure
}

task.resume()

Answer 4

更新了@fitmonk的Swift 3代码：

do {
    var request = URLRequest(url: URL(string: "https://www.example.com/api/v1")!, cachePolicy: .useProtocolCachePolicy, timeoutInterval: 10.0)

    let config = URLSessionConfiguration.default
    let session = URLSession(configuration: config)

    let task = session.dataTask(with: request, completionHandler: {(data, response, error) in

         if error != nil {

              print(error!.localizedDescription)

         }

         else {
              print(response)
         }
     })

    task.resume()
}

catch {
// handle the error
}

Answer 5

session.dataTaskWithRequest(request, completionHandler: {(data: NSData!, response: NSURLResponse!, error: NSError!) in 
    //code
)}

希望Xcode会更新以支持这些的自动完成，因为语法有点棘手，并且当这样使用时，Swift似乎不支持声明返回类型。

Answer 6

Swift 4.2

    let url = URL(string: "http://url.com")!
    let request = URLRequest(url: url)
    let config = URLSessionConfiguration.default
    let session = URLSession(configuration: config)

    let task = session.dataTask(with: request, completionHandler: {(data, response, error) in
        print(String(data: data!, encoding: .utf8)!)
    });

    task.resume()

如何在Swift中使用NSURLSessionDataTask

6 个答案: