Questions tagged [dispatch-async]
437 questions
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Create UIDocument on the fly in UIActivityItemProvider
I am using Core Data to store my user's data. I want to offer a Share button in the UI to export the data wherever they wish. I made a class conforming to UIActivityItemSource. It is successful when it simply returns a Data object from…
Bob Peterson
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What is the difference between these two Dispatch Queues?
I have seen this code used around on the web
let highQueue = DispatchQueue.global(qos: .userInteractive)
let videoDataOutputQueue = DispatchQueue(label: "com.apple.sample.capturepipeline.video", attributes: [], target: highQueue)
The second one…
Duck
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What happens if I put Dispatch.main.async block inside Dispatch.global.async?
I have a case where I am saving data to Realm Database inside Dispatch.global in background thread then inside same thread I have called Dispatch.main.async to fetch data from Realm and update UITableView Data.
The problem is I am getting less…
Manish Patel
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1 answer
Nested DispatchGroup
I try use nested DispatchGroup, there is my code :
class TranslateService {
private let myGroup = DispatchGroup()
func translateText(text:[String],closure:@escaping ((_ success:String?,_ error:Error?) -> Void)) {
var…
ava
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1 answer
Waiting for two different REST/Network calls to complete
I am making a lot of calls using REST and decided to separate these connection calls into a separate object, to be called from my UI classes. Here is the function I am using, it will not wait for the requests to be complete. I am not sure what I…
BriOnH
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asyncAfter with no time seems delay - Swift
Eventually I have used asyncAfter feature in swift with no time, and it does some delay and seems different with normal code.
Code with async:
DispatchQueue.main.asyncAfter(deadline: .now() + 0.0 , execute: {
self.updateUI()
})
Normal…
Saranjith
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Can we update UI from background Thread?
Hello iOS experts just to clear my concept I have a bit confusion about UI updation from Main Thread. Apple requirements are that all UI related stuff should be carried out in main Thread.So to test:
Case1: I dispatch a task to a global dispatch…
Nisar Ahmad
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NSTimer stop but unable to go to next page
I am using NSTimer to call a device to take photos every 24.5 second.
dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{
dispatch_async( dispatch_get_main_queue(), ^{
_photoTimer = [NSTimer…
Satty
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Display UIActivityIndicator while loading API data safely
I'm working on this app and have developed a full API for it. However, now that I've come to the front end part (the IOS app), I'm not sure how to load that data the right way.
I have made this class to make requests a little bit easier, but I get…
user6914372
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2 answers
Initialising UIView in main thread from a background thread
In a global, async closure, I'd like to initialise a UIView on the main thread. I thought this code would possibly do it, but I get an Analyser warning:
UIView.init(frame:) must by used from the main thread only.
let view: UIView = { // Line with…
Josh Paradroid
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2 answers
Why does DispatchQueue not respect QoS?
I'm trying to run multiple tasks on the main queue, some more urgent than others. I'm using DispatchQoS to do this:
func enqueue(_ prio: Int) {
let qos = DispatchQoS(qosClass: .userInteractive, relativePriority: prio)
…
Kartick Vaddadi
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Which method in react life cycle call after dispatch process and before render
I have a state that specify which component render(component A or B).
This state is determined when my action dispatch specific type(for example GO_TO_B or GO_TO_A).
Then I need to fetch some config from server to render component A. I want these…
mahdi jirofti
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2 answers
Dispatch queue clear explanation
I know there are already a lot of posts about dispatch queues, async tasks etc. ,but I can't retrieve a useful explanation out of these posts, because there are too many distractions because of the extra code. I there someone who can give me a clear…
Sven Cozijn
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EXC_BAD_ACCESS when using dispatch_async
We have recently revised our threading mechanism in favour of using dispatch_async's in most places (after doing a lot of reading about NSOperation vs dispatch_async)*. Then our code started crashing with EXC_BAD_ACCESS in various parts of the code,…
Ege Akpinar
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Do Dispatch queues wait for asynch NSURLSession calls to return before executing next job in queue?
I am executing NSURLSession requests to fetch JSON objects from a cloud service, most of these are calls are synch and have no dependencies but in one instance I have a dependency to take into account, I have to ensure that 2 NSURLSessions are…
Matt Douhan
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