read

I would have expected the process to be similar to iOS equivalence (UIView), but nope.

Yet I am no longer surprised :D

The Swift Code

To load a view from the nib file requires some code to:

1. Load nib from bundle and instantiate
2. Add the root view (contentView) to the custom view
3. Create constraints to fill the root view (the code uses cartography)

class MyView: NSView {

    @IBOutlet var contentView: NSView!

    override init(frame frameRect: NSRect) {
        super.init(frame: frameRect)
        setup()
    }

    required init?(coder decoder: NSCoder) {
        super.init(coder: decoder)
        setup()
    }

    private func setup() {
        let bundle = Bundle(for: type(of: self))
        let nib = NSNib(nibNamed: .init(String(describing: type(of: self))), bundle: bundle)!
        nib.instantiate(withOwner: self, topLevelObjects: nil)

        addSubview(contentView)
        constrain(self, contentView) { view, subview in
            subview.edges == view.edges
        }
    }

}

Setting up the xib

1. Create a xib file named the same, that is MyView.xib
2. Set File’s Owner > Class > MyView
3. Connect the root view to the contentView IBOutlet

With that, you can create the view programmatically with MyView() or via Interface Builder.