CODEWITHSUNDEEP
iosobjective-cswift
rjg
rjg

Reputation: 23

Obj C to Swift Conversion - Closures

How would I call this using Swift? Can't seem to get the right syntax!

@property (nonatomic, copy) void(^testBlock)(UIImage *image);

So far I've got:

imag.testBlock({(image:UIImage)->Void in
    println("test")
})

But it's giving me an error:

(UIImage) -> Void is not convertible to UIImage

Upvotes: 0

Views: 145

Answers (3)

Cezar
Cezar

Reputation: 56352

Your Objective-C property is a block that takes an UIImage parameter. When you do 

imag.testBlock({(image:UIImage)->Void in
    println("test")
})

You are calling the block and passing in another block, which doesn't make sense for your situation.

All you need is imag.testBlock(UIImage(named: "some_image"))

Upvotes: 0

GoZoner
GoZoner

Reputation: 70165

Your testBlock is an Objective-C property bound to a function. So, in your problem code, are you assigning testBlock or are you calling the function bound to testBlock?

imag.testBlock = { (image:UIImage) -> Void in
  println ("test")
}

then to use:

imag.testBlock (/* call with some image */)

Upvotes: 1

Youri Nooijen
Youri Nooijen

Reputation: 488

When defining a closure: Closures are typically enclosed in curly braces { } and are defined by a function type () -> (), where -> separates the arguments and the return type, followed by the in keyword which separates the closure header from its body.

{ (params) -> returnType in
  statements
}

See: http://fuckingswiftblocksyntax.com/

So in your case you shouldn't use Void as returnType, when you want to return an UIImage

imag.testBlock( { (image: UIImage) -> UIImage in
     return UIImage(....) 
}

Upvotes: 0

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