Xcode Error对成员＆＃39; dataTask（with：completionHandler：）＆＃39;的模糊引用

Question

我有一个swift 2.3项目，我刚刚更新到swift 3.0，以下代码破了。

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

        if error != nil {
            print("error=\(error)")
            return
        }

        print("response = \(response)")

        let responseString = NSString(data: data!, encoding: String.Encoding.utf8)
        print("responseString = \(responseString)")
    }) 
    task.resume()

我不知道如何解决它

Answer 1

如果request是NSURLRequest而不是URLRequest，则可以收到该错误。

let url = URL(string: urlString)!
let request = URLRequest(url: url)

let task = URLSession.shared.dataTask(with: request) { data, response, error in
    guard let data = data, error == nil else {
        print("error=\(error)")
        return
    }

    print("response = \(response)")

    let responseString = String(data: data, encoding: .utf8)
    print("responseString = \(responseString)")
}
task.resume()

或者，如果您要改变URLRequest，请使用var：

let url = URL(string: urlString)!
var request = URLRequest(url: url)
request.httpMethod = "POST"
request.httpBody = ...

let task = URLSession.shared.dataTask(with: request) { data, response, error in
    guard let data = data, error == nil else {
        print("error=\(error)")
        return
    }

    print("response = \(response)")

    let responseString = String(data: data, encoding: .utf8)
    print("responseString = \(responseString)")
}
task.resume()

另外，请注意，我已将NSString替换为String。