我有一个使用NSURLSessionDelegate类（MySession）的函数，它获取重定向URL并使用NSURLSessionTask检查它的状态代码。当用户离开当前ViewController时，我的总体目标是停止任何正在进行的操作。我是否通过以下代码正确地做到了这一点？我知道你无法取消正在进行的NSOperation，但是这段代码似乎并没有像我想要的那样正确取消新的操作。
var newQueue = NSOperationQueue()
var operation = NSBlockOperation()
}
override func viewDidDisappear(animated: Bool) {
newQueue.cancelAllOperations()
}
func myFunction {
for item in myArray{
if let urlAsString = item.url.description as? String {
operation = NSBlockOperation(block: {
if self.operation.cancelled {return}
MySession.getDataFromServerWithSuccess(urlAsString, noRedirect: false) { result in
switch result {
case .Success:
if self.operation.cancelled {return}
//Customizing Request
let request = NSMutableURLRequest(
URL: pin.url,
cachePolicy: .ReloadIgnoringLocalAndRemoteCacheData,
timeoutInterval: 5.0)
request.HTTPMethod = "GET"
var statusCode = Int()
let session = NSURLSession.sharedSession()
let task = session.dataTaskWithRequest(request) {urlData, response, responseError in
if self.operation.cancelled {return}
if let httpResponse = response as? NSHTTPURLResponse {
statusCode = httpResponse.statusCode
switch statusCode {
case _ where statusCode < 500 && statusCode > 299:
default:
break;
}
}
guard responseError == nil else {
print("Error during GET request on redirect: \(responseError)")
return
}
}
task.resume()
self.pinsThatHaveBeenChecked.append(pin)
dispatch_async(dispatch_get_main_queue(),{
self.collectionView?.reloadData()
})
case let .Failure(error):
if self.operation.cancelled {return}
print("Error with \(pin.descriptionText): \(error)")
case let .NoResponse:
if self.operation.cancelled {return}
print("No response for \(pin.descriptionText) \(pin.identifier)")
default: break
}
}
})
operation.qualityOfService = .Background
newQueue.addOperation(operation)
}
dispatch_async(dispatch_get_main_queue(),{
self.collectionView?.reloadData()
})
}