I have an app in Objective C that I'm transitioning to Swift. In Objective C, I have this method:
[self.view performSelector:@selector(someSelector) withObject:self afterDelay:0.1f];
I'm working with Swift and I can't figure out how to do this. I've tried:
self.view.performSelector(Selector("someSelector"), withObject: self, afterDelay: 0.1)
Here's the error that I get: 'performSelector' is unavailable: 'performSelector' methods are unavailable
What call would I use to call a method afterDelay
?
UPDATE
Here's what I ended up with:
extension NSObject {
func callSelectorAsync(selector: Selector, object: AnyObject?, delay: NSTimeInterval) -> NSTimer {
let timer = NSTimer.scheduledTimerWithTimeInterval(delay, target: self, selector: selector, userInfo: object, repeats: false)
return timer
}
func callSelector(selector: Selector, object: AnyObject?, delay: NSTimeInterval) {
let delay = delay * Double(NSEC_PER_SEC)
let time = dispatch_time(DISPATCH_TIME_NOW, Int64(delay))
dispatch_after(time, dispatch_get_main_queue(), {
NSThread.detachNewThreadSelector(selector, toTarget:self, withObject: object)
})
}
}
This question is related to
ios
objective-c
swift
xcode6
You could do this:
var timer = NSTimer.scheduledTimerWithTimeInterval(0.1, target: self, selector: Selector("someSelector"), userInfo: nil, repeats: false)
func someSelector() {
// Something after a delay
}
let timer = Timer.scheduledTimer(timeInterval: 0.1, target: self, selector: #selector(someSelector), userInfo: nil, repeats: false)
func someSelector() {
// Something after a delay
}
Swift 4
DispatchQueue.main.asyncAfter(deadline: .now() + 0.1) {
// your function here
}
Swift 3
DispatchQueue.main.asyncAfter(deadline: .now() + .seconds(0.1)) {
// your function here
}
Swift 2
let dispatchTime: dispatch_time_t = dispatch_time(DISPATCH_TIME_NOW, Int64(0.1 * Double(NSEC_PER_SEC)))
dispatch_after(dispatchTime, dispatch_get_main_queue(), {
// your function here
})
Swift is statically typed so the performSelector:
methods are to fall by the wayside.
Instead, use GCD to dispatch a suitable block to the relevant queue — in this case it'll presumably be the main queue since it looks like you're doing UIKit work.
EDIT: the relevant performSelector:
is also notably missing from the Swift version of the NSRunLoop
documentation ("1 Objective-C symbol hidden") so you can't jump straight in with that. With that and its absence from the Swiftified NSObject
I'd argue it's pretty clear what Apple is thinking here.
Source: Stackoverflow.com