How to run code asynchronously using GCD async()
Swift version: 5.1
iOS gives you two ways to run code asynchronously: GCD and performSelector(inBackground:). The first option looks like this:
DispatchQueue.global(qos: .userInitiated).async { [unowned self] in
self.yourCodeHere()
}The .userInitiated quality of service setting is the highest priority after userInteractive. You can also use utility (lower priority) or .background (lowest priority.)
The second option looks like this:
performSelector(inBackground: #selector(yourCodeHere), with: nil)You'll need to replace yourCodeHere with the name of an actual method. If you want to pass a parameter, make sure and use “yourCodeHere:" and provide a value for the with parameter.
SAVE 20% ON iOS CONF SG The largest iOS conference in Southeast Asia is back in Singapore for the 5th time in January 2020, now with two days of workshops plus two days of talks on SwiftUI, Combine, GraphQL, and more! Save a massive 20% on your tickets by clicking on this link.
Available from iOS 4.0 – see Hacking with Swift tutorial 9
Similar solutions…
- How to run code on the main thread using GCD async()
- How to send notifications asynchronously using NotificationQueue
- How to run code when your app is terminated
- How to use Instruments to profile your SwiftUI code and identify slow layouts
- How to run code after a delay using asyncAfter() and perform()
About the Swift Knowledge Base
This is part of the Swift Knowledge Base, a free, searchable collection of solutions for common iOS questions.
