I have a simple class where I declare a block as a variable:
class MyObject : NSObject
{
var progressBlock:(progress:Double) -> ()?
init() { }
}
As far as I understand, if defined this way, progressBlock
does not have to be initialized in the init()
initializer
However, when I try to compile I get his error:
Property 'self.progressBlock' not initialized at super.init
So the question is, how do I create an optional progressBlock
, so I don't get this error?
The way you have written it, the compiler assumes progressBlock is a closure that returns an optional empty tuple instead of an optional closure that returns an empty tuple. Try writing it like this instead:
class MyObject:NSObject {
var progressBlock:((progress:Double) -> ())?
init() {
progressBlock = nil
progressBlock = { (Double) -> () in /* code */ }
}
}
Adding to connor's reply. An optional block can be written as:
var block : (() -> ())? = nil
Or as an explicit Optional
:
var block : Optional<() -> ()> = nil
Or better yet, with a custom type
typealias BlockType = () -> ()
var block : BlockType? = nil
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