xcode - 二元运算符 != 不能应用于 NSUrlConnection!.Type 和 NilLiteralConvertible 类型的操作数

Question

我是 Swift 的新手，我终于完成了我的第一个应用程序，但是当更新发布时，我的代码完全搞砸了。我代码中的大多数错误是由 sendSynchronousRequest 引起的调用中的额外参数“错误” 错误。我试图改变它，最后想到了这个。

    var url = NSURL(string: "http://****")
    var request = NSMutableURLRequest(URL: url!, cachePolicy: NSURLRequestCachePolicy.ReturnCacheDataElseLoad, timeoutInterval: Double.infinity);
    if IJReachability.isConnectedToNetwork(){
        request = NSMutableURLRequest(URL: url!, cachePolicy: NSURLRequestCachePolicy.UseProtocolCachePolicy, timeoutInterval: Double.infinity);
    }
    var response: NSURLResponse?
    let data = NSURLConnection!.self
    do {
        let data = try NSURLConnection.sendSynchronousRequest(request, returningResponse: &response)
    } catch (let e) {
        print(e)
    }
    if data != nil {
        var dataArray = JSON(data: data)
        let dutch_sentence = dataArray[id]["dutch_sentence"]
        let polish_sentence = dataArray[id]["polish_sentence"]
        let navigationTitle = dutch_sentence.string!.uppercaseString
        self.title = navigationTitle

        //Populate labels
        dutchSentenceLabel.text = dutch_sentence.string!
        polishSentenceLabel.text = polish_sentence.string!

    }

但现在它说:

Binary operator != cannot be applied to operands of type NSUrlConnection!.Type and NilLiteralConvertible

对于行 if data != nil {

Answer 1

考虑使用 NSURLSessionTask 而不是 NSUrlConnection，后者在 iOS9 中已弃用，例如:

var url = NSURL(string: "http://****")
var request = NSMutableURLRequest(URL: url!, cachePolicy: NSURLRequestCachePolicy.ReturnCacheDataElseLoad, timeoutInterval: Double.infinity);
    if IJReachability.isConnectedToNetwork(){
        request = NSMutableURLRequest(URL: url!, cachePolicy: NSURLRequestCachePolicy.UseProtocolCachePolicy, timeoutInterval: Double.infinity);
    }
let config = NSURLSessionConfiguration.defaultSessionConfiguration()
let session = NSURLSession(configuration: config)

let task : NSURLSessionDataTask = session.dataTaskWithRequest(request, completionHandler: {(data, response, error) in
    if data != nil {
        var dataArray = JSON(data: data)
        let dutch_sentence = dataArray[id]["dutch_sentence"]
        let polish_sentence = dataArray[id]["polish_sentence"]
        let navigationTitle = dutch_sentence.string!.uppercaseString
        self.title = navigationTitle

        //Populate labels
        dutchSentenceLabel.text = dutch_sentence.string!
        polishSentenceLabel.text = polish_sentence.string!

    }
});