Xcode8: using literary images as part of

Question

I am currently updating a project to use image literals to take advantage of optional images. The project imports various structures, and the frames contain images.

In the framework, we had to declare an extension on UIImage in order to override the initializer, because it was looking for the image in the wrong bundle. We did something like:

 extension UIImage { convenience init?(framework_named imageName: String) { let bundle = Bundle(for: ClassNameInFramework.self) self.init(named: imageName, in: bundle, compatibleWith: nil) } } 

I also want to use literary sheets in a frame, but, as before, literals are looking for the wrong package for the image, and application crashes .

Does anyone know how to specify the literal image to which the package is looking for an image?

Answer 1

I found a pretty simple workaround and was amazed not to find it anywhere else in the posts. I would like it to be more elegant, but preferable to use the ugly UIImage(named:in:compatibleWith:) string typifier, in my opinion.

We mainly use the _ExpressibleByImageLiteral protocol, which is used by Xcode to determine if a type is a literal image literal like this:

 struct WrappedBundleImage: _ExpressibleByImageLiteral { let image: UIImage init(imageLiteralResourceName name: String) { let bundle = Bundle(for: ClassInFramework.self) image = UIImage(named: name, in: bundle, compatibleWith: nil)! } } 

Note that I'm using a wrapper instead of a subclass of UIImage , which looks like the best option. Unfortunately, classes like UIImage are not intended to be a subclass, and you will find that you have a lot of headaches.

And now its use will be:

 let image = (🏞 as WrappedBundleImage).image 

Not as concise as a regular image literal, but still compilation time is checked :). We just have to remember to cast as , otherwise our custom initializer will not be called.

You can also do something like this:

 extension UIImage { static func fromWrappedBundleImage(_ wrappedImage: WrappedBundleImage) -> UIImage { return wrappedImage.image } } 

And now we can use it as follows:

 UIImage.fromWrappedBundleImage(🏞) 

Hope this helps!