Cancel NSOperationsQueue - ios

Question

I am trying to cancel my NSOperationsQueue and remove all the operations from the queue. I called the method "cancelAllOperations()" but this doesnt remove the operation from queue, I am aware that this method only adds a flag to the operation.
How do I go about removing all operations from my queue? Or prevent the operation queue from executing operations that have a flag?
private let mediaDownloadOperationQueue: NSOperationQueue = {
let queue = NSOperationQueue()
queue.maxConcurrentOperationCount = 1
queue.qualityOfService = .Background
return queue
}()
func startDownloadProcess() {
guard downloadSwitchState == true else { return }
let context = DataBaseManager.sharedInstance.mainManagedObjectContext
let mediasToDownload = self.listOfMediaToDownload(context)
for media in mediasToDownload {
downloadMedia(media)
}
}
private func downloadMedia(media: Media) {
//check if operation already exist
for operation in mediaDownloadOperationQueue.operations {
let operation = operation as! MediaDownloadOperation
if operation.media.objectID == media.objectID { return }
}
//HERE I am adding the operation to queue
mediaDownloadOperationQueue.addOperation(MediaDownloadOperation(media: media))
}
//EDIT: Here is my MediasDownloadOperation
import Foundation
import Alamofire
class MediaDownloadOperation: BaseAsyncOperation {
let media: Media
init(media: Media) {
self.media = media
super.init()
}
override func main() {
guard let mediaSourceURI = media.sourceURI
else {
self.completeOperation()
return
}
var filePath: NSURL?
let destination: (NSURL, NSHTTPURLResponse) -> (NSURL) = {
(temporaryURL, response) in
if let directoryURL = NSFileManager.defaultManager().URLsForDirectory(.DocumentDirectory, inDomains: .UserDomainMask).first, let suggestedFilename = response.suggestedFilename {
filePath = directoryURL.URLByAppendingPathComponent("\(suggestedFilename)")
return filePath!
}
return temporaryURL
}
RequestManager.sharedAlamofireManager.download(.GET, mediaSourceURI, destination: destination).response {
(request, response, data, error) -> Void in
if let filePath = filePath where error == nil {
let saveToCameraRoll = self.media.saveToCameraRoll?.boolValue == true
self.media.fileLocation = filePath.lastPathComponent
self.media.saveToCameraRoll = false
DataBaseManager.sharedInstance.save()
if saveToCameraRoll {
self.media.saveMediaToCameraRoll(nil)
}
}
self.completeOperation()
NSNotificationCenter.defaultCenter().postNotificationName(MediaDownloadManager.MediaIsDownloadedNote, object: nil)
}
}
}

Answer 1

Adding a conditional to test to see if operation has cancelled seemed to have solved the problem:
RequestManager.sharedAlamofireManager.download(.GET, mediaSourceURI, destination: destination).response {
(request, response, data, error) -> Void in
//Only download if logged in
if (self.cancelled == false){
print("RAN operation!")
if let filePath = filePath where error == nil {
let saveToCameraRoll = self.media.saveToCameraRoll?.boolValue == true
self.media.fileLocation = filePath.lastPathComponent
self.media.saveToCameraRoll = false
DataBaseManager.sharedInstance.save()
if saveToCameraRoll {
self.media.saveMediaToCameraRoll(nil)
}
}
self.completeOperation()
NSNotificationCenter.defaultCenter().postNotificationName(MediaDownloadManager.MediaIsDownloadedNote, object: nil)
}else{
print("did not run operation! was cancelled!")
self.completeOperation()
}
}