How to specify nested custom view class?

Question

Available nested classes SuperView and NestedView.

class SuperView : UIImageView {

    class NestedView : UIImageView {
        var text : String = "Nested View"
    }

    var text : String = "Super View"
    var nested : NestedView?

}

I would like to set for a UIImageView the property named "Custom Class Name" to value "NestedView" inside the inspector of the storyboard scene. But the Interface Builder couldn't find "NestedView" class.

Answer 1

At this time, I think that Interface Builder only recognizes the names of Objective-C classes. You can still make Interface Builder find a nested class with the @objc keyword:

class SuperView: UIView {
  @objc(SVNestedView) class NestedView: UIImageView {
  }
}

Then, in Interface Builder, specify that th view is of class SVNestedView. Since Objective-C isn't namespaced, you still need to pick unique names for each nested class, but at least the Swift side is properly namespaced.

Answer 2

In Swift, an instance of an inner class is independent of any instance of the outer class. It is as if all inner classes in Swift are declared using Java's static.

I don't think this class design suits your requirement. What you need to do is, you need to create a new class outside your view, and create some sort of a composition. This will surely work out for you.

Here is some modification to your code:

class SuperView : UIImageView {
    var text : String = "Super View"
    var nested : NestedView = NestedView()
}

class NestedView : UIImageView {
    var text : String = "Nested View"
}

Answer 3

I think it impossible to specify an inner class in a storyboard like SuperView.NestedView so far. So I makes a class extended from an inner class, then specifies it in a storyboard like SuperView_NestedView. It works for me.

final class SuperView_NestedView: SuperView.NestedView {} // Specifies this class in the storyboard 
class SuperView : UIImageView {

    class NestedView : UIImageView {
        var text : String = "Nested View"
    }

    var text : String = "Super View"
    var nested : NestedView?

}

This view can be referred as SuperView.NestedView from a ViewController because SuperView_NestedView is extended from SuperView.NestedView.

class TheViewController: UIViewController {
    @IBOutlet var nestedView: SuperView.NestedView!