Swift: Property conforming to a specific class and in the same time to multiple protocols

Question

In Objective-C, it\'s possible to write something like that:

@property(retain) UIView *myView;

But how can

Answer 1

One and probably a bit ugly one of the ways to do that, is to create a wrapper protocol for UIView:

protocol UIViewRef {
    var instance: UIView { get }
}

Now it is possible to create a protocol which implements Protocol1, Protocol2 and UIViewRef, which is going to be used to get the UIView itself:

protocol MyUIViewProtocol: UIViewRef, Protocol1, Protocol2 { }

And last step will be implementing UIViewRef protocols for your UIViews, which, in you case, as I understand, already implement Protocol1 and Protocol2:

// SomeOfMyViews already implements Protocol1 and Protocol2
extension SomeOfMyUIViews: MyUIViewProtocol {
    var instance: UIView { return self }
}

As the result we have MyUIViewProtocol, implementers of which hold a reference to a UIView and each of them implement Protocol1 and Protocol2. One caveat though - to get the UIView itself, we need to ask it's reference from instance property. For example

// Lets say we're somewhere in a UIViewController
var views: [SomeOfMyUIView] = // Get list of my views
views.forEach { self.view.addSubview($0.instance) }