Skip to main content. This browser is no longer supported. Download Microsoft Edge More info. Contents Exit focus mode. Objective-C selectors in Xamarin.
The width parameter, a CGFloat , is mapped to nfloat. Handle, selector. Zero : font. Handle, width, mode ; Had the returned value been a structure that was less than 8 bytes in size like the older SizeF used before switching to the Unified APIs , the above code would have run on the simulator but crashed on the device.
CGSize size; if Runtime. Zero: font. Handle, width, mode ; Invoking a selector Invoking a selector has three steps: Get the selector target. This should probably mention that the selector needs a ":" at the end if it takes an argument. It should also be pointed out that the Cocoa frameworks expect an Objective-C style method name.
If your method takes an argument you will need a ':' if it takes 2 arguments, size:andShape: , if the first argument is named you may need a With , i. Is there anyway to add validation around passing the "selector" as a string? IE compiler warn us when we misspell, etc. Show 12 more comments. Plain, target: self, action: Selector "method" self. Oscar Swanros Oscar Swanros This answer is helpful but the answer below with objc is more appropriate.
When you are passing the selector string in as a variable or parameter, you'll need to let the compiler know its a selector using the Selector function. Show 1 more comment. Selector keyword is not mandatory. I didn't need to include timer: NSTimer in my method signature for it to be called. Swift 2. Joseph Francis 1 1 gold badge 13 13 silver badges 21 21 bronze badges. Kyle Clegg Kyle Clegg Swift 4. Kevin Singh 6 6 silver badges 14 14 bronze badges. You forgot to put objc before func which is required in Swift 4.
Rob Sanders Rob Sanders 4, 3 3 gold badges 28 28 silver badges 55 55 bronze badges. It can also be internal , thus not specifying any access modifier. Martin Cazares Martin Cazares Scooter Scooter 3, 4 4 gold badges 29 29 silver badges 45 45 bronze badges. I was using NSTimer 0. DID work!? Strange but thanks Scooter for you answer! David thanks for your suggestion. Don't worry about it, no one can be expected to read the documentation about every single method in every API ; — David Ganster.
Plain, target: self, action:Selector "logout". Jony T Jony T 3 3 silver badges 15 15 bronze badges. Krunal Krunal Please stop doing this. It helps no one. How is this any different from Swift 3.
And why did you think it necessary to add another answer to this when it already has about 20 answers? Try these answers in swift 4 and see. None these will work without editing. Please do not mark any statement as spam without ensuring its impotance — Krunal.
So is there any reason you couldn't edit the existing, accepted answer? About Hacking with Swift. What is a selector? Swift version: 5. Was this page useful? Add a Comment. In the above case, this works, too: selector aController. For example, with this function: objc func aMethod a:Int the correct selector would be Selector "aMethodWithA:" because of the standard name-translation rules.
Posted by QuinceyMorris. Posted by PatriceRapaport. The resulting selector is based entirely on the method signature. No, it doesn't work like that. You have two choices: 1.
For example, you can write Selector "aMethod" or selector "aMethod". For example, you can write selector aController. But you can't mix the two.
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