Swift:致命错误:在解开可选值时出乎意料地发现了无

Question

我正在尝试访问REST Web服务，但是它给出了这一点 - 致命错误：在解开可选值时出乎意料地找到了无。

以下是代码 - 所以我有这个Restparser类 -

protocol RESTParserDelegate
{
    func getReceiveData(data:NSMutableData,sender:RESTParser)
}
class RESTParser: NSObject, NSURLConnectionDataDelegate 
{
var receiveData: NSMutableData!
var requestConnection: NSURLConnection!
var delegate: RESTParserDelegate?
func receiveData(resData:NSMutableData){
    receiveData = resData
}
func requestConnection(reqConn:NSURLConnection){
    requestConnection = reqConn
}
func httpRequest(myRequest:NSMutableURLRequest){
    self.requestConnection = NSURLConnection(request: myRequest, delegate: self)
}
// NSURLConnectionDataDelegate methods
func connection(connection: NSURLConnection, didReceiveData data: NSData){
    self.receiveData?.appendData(data)
}
func connectionDidFinishLoading(connection: NSURLConnection){
    self.delegate?.getReceiveData(receiveData, sender: self) // error @ this line
    self.delegate = nil
    self.receiveData = nil
    self.requestConnection = nil
}
func connection(connection: NSURLConnection, didFailWithError error: NSError){
    NSLog("Failed with error - %@ ",error.localizedDescription)
}
func parseData(data:NSMutableData){
}
}

错误是 @此行-self.delegate？.getReceivedata（接收到，发件人：self）

并从我的项目详细信息查看控制器中调用此功能 - 但是一旦getReceivedata方法称为"致命错误"。

class ProjectDetails_tab: UIViewController, RESTParserDelegate{
override func viewDidLoad() {
    super.viewDidLoad();
    //var projectData: NSDictionary = [String:String]()
    var url:String = "http://domianName.com"
    var nsURL = NSURL(string: url)
    var createrequest: NSMutableURLRequest = NSMutableURLRequest(URL: nsURL!)
    createrequest.HTTPMethod = "GET"
    var rest = RESTParser()
    rest.delegate=self
    rest.httpRequest(createrequest)
}
func getReceiveData(data:NSMutableData,sender:RESTParser){   
}    
}

Answer 1

尚不清楚代码中哪一行的致命错误。但是您可以重新检查您的委托对象或：

// NSURLConnectionDataDelegate methods
func connection(didReceiveResponse: NSURLConnection, didReceiveResponse response: NSURLResponse) {
    // Recieved a new request, clear out the data object
    self.receiveData = NSMutableData()
}
func connection(connection: NSURLConnection, didReceiveData data: NSData){
    self.receiveData?.appendData(data)
}
func connectionDidFinishLoading(connection: NSURLConnection!) {
    // Request complete, self.data should now hold the resulting info
}