ios - Swift3 中的 "Cannot convert value of type"错误

Question

我遇到了以下错误:

使用 Xcode-beta 5 和 Swift。在测试版 4 中它工作正常。谁能帮帮我？

extension UIImageView {
    public func imageFromUrl(_ urlString: String) {
        if let url = URL(string: urlString) {
            let request = URLRequest(url: url)
            NSURLConnection.sendAsynchronousRequest(request, queue: OperationQueue.main) {
                (response: URLResponse?, data: Data?, error: NSError?) -> Void in
                self.image = UIImage(data: data!)
            }
        }
    }
}

Answer 1

读取错误。查看您的 error 参数的类型。您已将其声明为 NSError，但错误消息告诉您应将其声明为 Error，而不是 NSError。

所以你的代码应该是:

extension UIImageView {
    public func imageFromUrl(_ urlString: String) {
        if let url = URL(string: urlString) {
            let request = URLRequest(url: url)
            NSURLConnection.sendAsynchronousRequest(request, queue: OperationQueue.main) {
                (response: URLResponse?, data: Data?, error: Error?) -> Void in
                self.image = UIImage(data: data!)
            }
        }
    }
}