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Questions tagged [dispatch-async]

437 questions
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votes
0 answers

DispatchGroup notify() doesn't get called

I have to wait for the completion until the user touches the Try Again button to call the same function again. All works fine the first time but when I press it again, the notfy() method doesn't get called. Here is the playground class to simulate…
ios_dev
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Completion Handler dispatch_async is giving error?

I have completion handler in following function static func fetchFeatureApp(completionHandler:@escaping ([AppCategory1])->()){ let urlString="http://ebmacs.net/ubereats/Api/all_product?id=1" let url = URL(string: urlString)! …
user8298737
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6 answers

How to execute second dispatch_async when previous first dispatch_async is finished?

I would like to add a dispatch_async sequentially but I would like them not to be launched randomly. I would like for example : dispatch_async 1 begins... dispatch_async 1 ends. dispatch_async 2 begins... dispatch_async 2 ends. dispatch_async 3…
ΩlostA
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ios 10+, Swift 3+ - Cannot dismiss UIAlertController from Singleton instance

I have created an overlay to run while I run an async data grab to the server so that users won't continue pressing buttons in the UI until the data grab is done. I have put the function into a global singleton class and I call it while passing in a…
Erik Grosskurth
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1 answer

Properly manage dispatch queue to reduce phone heating iOS

CUSTOM_VIEW CLASS: I have made custom_view class which calculates value on itself and shows to user after every 1 sec. Calculation of values in custom_view based on properties/variable stored in custom_view instance. VIEWCONTROLLER CLASS: I…
nikdange_me
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1 answer

Long cycle blocks application

I hve following cycle in my app var maxIterations: Int = 0 func calculatePoint(cn: Complex) -> Int { let threshold: Double = 2 var z: Complex = .init(re: 0, im: 0) var z2: Complex = .init(re: 0, im: 0) var iteration: Int = 0 …
Dawy
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Swift 2 to 3 Migration dispatch_get_global_queue

I have the following code that I've been trying to translate into swift 3 from swift 2. Here is what I have so far. DispatchQueue.async(group: DispatchQueue.global(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0),execute: { …
Joseph Astrahan
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Dispatch_Async Won't Work After Firebase Call

I am creating an iOS app in Swift that uses Firebase as the backend. The app gets images from Firebase storage using this code: imageRef.downloadURLWithCompletion{ (URL, error) -> Void in print("Firebase sent something back!") …
Olivia Watkins
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2 answers

How to update UI from thread

My program "ThreadsNQueues" - see below - fills text lines with "A"s and "B"s concurrently on background threads. When a text line has been filled with 10 characters it will be appended to an output text buffer (it's a NSMutableString) and this…
user5924595
2
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1 answer

Parallel search with dispatch_async

I'm trying to implement a parallel-search algorithm. The concept is something like this: Start with a candidate & test if it is the desired value If not, generate more candidates and add them to the queue. Repeat until reaching the desired…
Jenny
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1 answer

Swift 2.0: Schedule background task to upload failed product uploads

I am developing an app which uploads a product (JSON) to server. Now, every product object consists of many images. A product is only uploaded to server if all images associated with that product have already been uploaded. In case all images for…
dashbashrumble
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1 answer

How to get nested asynchronous calls resolved before completion block

Here's the setup. I have a method that has a completion block in which I want to return a list of Items. These Items are fetched from an API. I'd like to have each of the fetches happen asynchronously but ultimately return the Items all…
H K
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Objective-C freezed GUI also with queue

I'm trying to understand queue in iOS; with this code dispatch_queue_t coda_thread=dispatch_queue_create("coda_thread",NULL); //UIPROGRESS VIEW for(i=0;i<=10;i=i+1) { dispatch_async(coda_thread, ^{ NSLog(@"CODA_THREAD"); …
volperossa
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Updating UI Dispatch_Async background download Swift

Im working on a folders/files application where users are able to download files to local disk. Whenever a user is downloading a file, I want to show a download bar that displays progress. to do so, I've created a protocol that allows my download…
SKYnine
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Unbalanced call to dispatch_group_leave() on CloudKit CompletionBlock

So I am building an iOS app working with CloudKit. A particular function calls for Products: func getAllProducts(){ //empty object in Singleton Class sharedStore.products.removeAllObjects() var products = NSMutableArray() //set up…
Joris416
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