Passing a swift function to objective-c
Passing a swift function to objective-c
- Subject: Passing a swift function to objective-c
- From: Kevin Meaney <email@hidden>
- Date: Thu, 16 Oct 2014 23:13:45 +0100
Hi,
I'm beginning to feel this above my pay grade as I can't seem to work it out.
I have a framework in Objective-C. I've been writing some tests for it, and to make life fun I've been writing the tests in Swift.
I have a property of a class in the objective-c framework declared like so:
@property (nonatomic, copy) CGImageRef (^createImage)(NSDictionary *);
In my tests I'm trying to write a function that I can assign to the property.
In the most basic form the function looks like this, I'm ignoring the passed in dictionary for the purposes of asking this question:
func createCGImage2(dictionary: [NSObject:AnyObject]) -> CGImage {
let jpegURL = NSBundle.mainBundle().URLForResource("myimage", withExtension:"jpg")
let imageSource = CGImageSourceCreateWithURL(jpegURL, nil)!
let theImage = CGImageSourceCreateImageAtIndex(imageSource, 0, nil)
return theImage
}
When I try to set the property with the function I get:
error: cannot convert the expression's type '([NSObject : AnyObject]) -> Unmanaged<CGImage>!' to type '(([NSObject : AnyObject]!) -> Unmanaged<CGImage>!)!?'
Now, if I have a function declared like so:
func createCGImageFromDictionary(dictionary: [NSObject:AnyObject]!) -> Unmanaged<CGImage>!
error: cannot convert the expression's type '([NSObject : AnyObject]!) -> Unmanaged<CGImage>!' to type '(([NSObject : AnyObject]!) -> Unmanaged<CGImage>!)!?'
I'm still a long way off. There's an extra () in there and an extra !? at the end that I really don't know how to interpret. Also I don't know how to convert the result of CGImageSourceCreateImageAtIndex to a Unmanaged<CGImage> as a return value.
I've been through various bits of the documentation, but something isn't clicking so that I understand how this stuff works so that I can try and solve it.
Kevin
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