Use KVO to observe the operations property of your queue, then you can tell if your queue has completed by checking for [queue.operations count] == 0. Somewhere in the file you’re doing the KVO in, declare a context for KVO like this (more info): static NSString *kQueueOperationsChanged = @”kQueueOperationsChanged”; When you setup your queue, do … Read more
You can use dispatch groups to fire an asynchronous callback when all your requests finish. Here’s an example using dispatch groups to execute a callback asynchronously when multiple networking requests have all finished. override func viewDidLoad() { super.viewDidLoad() let myGroup = DispatchGroup() for i in 0 ..< 5 { myGroup.enter() Alamofire.request(“https://httpbin.org/get”, parameters: [“foo”: “bar”]).responseJSON { … Read more
GCD is a low-level C-based API that enables very simple use of a task-based concurrency model. NSOperation and NSOperationQueue are Objective-C classes that do a similar thing. NSOperation was introduced first, but as of 10.5 and iOS 2, NSOperationQueue and friends are internally implemented using GCD. In general, you should use the highest level of … Read more