How to run code asynchronously using GCD async()
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.
Available from iOS 4.0 – see Hacking with Swift tutorial 9
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