swift - 网址(字符串 :) Cannot call value of non-function type 'String'

Question

我有以下代码，但出现错误。

if let userImageURL = user.image {
    let url = URL(string: userImageURL)
}

我应该如何创建网址？ URL(string:)应该带一个 String不是吗？这就是 userImageURL是。

编辑:这是我试图实现的代码示例。即使在这个例子中，我也遇到了同样的错误 catPictureURL

let catPictureURL = URL(string: "http://i.imgur.com/w5rkSIj.jpg")!

// Creating a session object with the default configuration.
// You can read more about it here https://developer.apple.com/reference/foundation/urlsessionconfiguration
let session = URLSession(configuration: .default)

// Define a download task. The download task will download the contents of the URL as a Data object and then you can do what you wish with that data.
let downloadPicTask = session.dataTask(with: catPictureURL) { (data, response, error) in
    // The download has finished.
    if let e = error {
        print("Error downloading cat picture: \(e)")
    } else {
        // No errors found.
        // It would be weird if we didn't have a response, so check for that too.
        if let res = response as? HTTPURLResponse {
            print("Downloaded cat picture with response code \(res.statusCode)")
            if let imageData = data {
                // Finally convert that Data into an image and do what you wish with it.
                let image = UIImage(data: imageData)
                // Do something with your image.
            } else {
                print("Couldn't get image: Image is nil")
            }
        } else {
            print("Couldn't get response code for some reason")
        }
    }
}

downloadPicTask.resume()

Answer 1

您需要像这样制作 URL 对象

let url = Foundation.URL(string:"your_url_string")