json - URLSession 错误

Question

我正在使用一个实际上是为 swift 2 编写的函数。我已经为 swift 3 做了调整。但我不断收到错误:

URLSession' produces '()', not the expected contextual result type 'URLSession!

我的代码是这样的:

func downloadItems() {

        let url: NSURL = NSURL(string: urlPath)!
        var session: URLSession!
        let configuration = URLSessionConfiguration.default


        session = URLSession(configuration: configuration, delegate: self, delegateQueue: nil)


        let task = session.dataTask(with: url as URL)

        task.resume()
    }

有人知道我做错了什么吗？

Answer 1

代替:

 session = URLSession(configuration: configuration, delegate: self, delegateQueue: nil)

这样做:

   session = {
        let session = URLSession(configuration: configuration, delegate: self, delegateQueue: nil)
        return session
    }()