nsoperation

I am trying to start again NSBlockOperation after completing or canceling it, but getting an error? Any one have any idea where is mistake? Thanks let imageURLs = ["http://www.planetware.com/photos-large/F/france-paris-eiffel-tower.jpg", "http://adriatic-lines.com/wp-content/uploads/2015/04/canal-of-Venice.jpg", "http://algoos.com/wp-content/uploads/2015/08/ireland-02.jpg", "http://bdo.se/wp-content/uploads/2014/01/Stockholm1.jpg"] class Downloader { class func downloadImageWithURL(url:String) -> UIImage! { let data = NSData(contentsOfURL: NSURL(string: url)!) return UIImage(data: data!) } }

I'm trying to run NSURLConnection async in a secondary thread (target is iOS4), for this I have created a concurrent NSOperation, I think I'm almost there, but am not clear on the following: 1) in iOS4 NSOperationQueue addOperation starts the operation in a new thread, because of the use of GCD, based on Technical Q&A QA1712 , however, my tests (simulator and iPad) show that start() is always called on the main thread, any idea, do I need a check here: if on main thread then spawn a new one? 2) if start was actually called on a secondary thread by addOperation(), then I could start my async

I'm about to create a series of NSOperation s and run them in a queue. They will all be sequential and run one at a time. These operations will fetch data from the web and create and save core data managed objects. How do I handle the situation where the application exits? As the operations run in detached threads, how can I make the main thread wait until the current operation is "safe" to quit? There are situations where I'm happy for the threads (operations) to exit before they are complete as on further app launches the job will continue and pick up where it left off. Many thanks, Mike

I’m an experienced C/C++ programmer coming up to speed on Objective C on the iPhone. I have done a lot of searching, but haven’t found a satisfactory answer on what must be a common question; I apologize if this is answered elsewhere, pointers would be appreciated. My app is very CPU intensive. The UI has a simple display that shows progress and a start/stop button. What is the best way to allocate the most possible CPU cycles to getting the work done, while still ensuring that the display is updated regularly and the start/stop button is responsive? I have read that you should not do work in

I want to do an Asynchrous NSURLConnection inside of an NSOperation on a background thread. it is because I'm doing some very expensive operations on the data as they come back. This is a very similar question to what they asked here: How do I do an Asynchronous NSURLConnection inside an NSOperation? but the difference is that I run the connection in another class. Here is my first attempt: In my MainViewController: @property (nonatomic, strong) NSOperationQueue *requestQueue; #pragma mark - Lazy initialization - (NSOperationQueue *)requestQueue { if (!_requestQueue) { _requestQueue = [

I have an Operation subclass and Operation queue with maxConcurrentOperationCount = 1. This performs my operations in a sequential order that i add them which is good but now i need to wait until all operations have finished before running another process. i was trying to use notification group but as this is run in a for loop as soon as the operations have been added to the queue the notification group fires.. How do i wait for all operations to leave the queue before running another process? for (index, _) in self.packArray.enumerated() { myGroup.enter() let myArrayOperation = ArrayOperation