Swift: create a flat array of views from view hierarchy

Question

I have a view hierarchy and I need to flatten it into a linear array, say:

+ rootView 0 - subView 1 - subview 2 + subview 3 - subview 3.1 - subview 3.2 - subview 4

I need an array of:

[0, 1, 2, 3, 3.1, 3.2, 4]

I wondered if map or flatMap can be used, or if I have to use the traditional way like a breadth-first traverse?

Thanks!

Answer 1

I would use a recursive function, which you can call on the rootView.

func flattenSubviews(view: UIView) -> [UIView] {
    
    var flatArray: [UIView] = []
    flatArray.append(view)
    
    for subview in view.subviews {
        flatArray += flattenSubviews(view: subview)
    }
    return flatArray
}

.

let flattenedViews = flattenSubviews(view: rootView)

A slightly more abstract way of writing the above by putting it in an extension:

extension UIView {

    func subviewsFlattened() -> [UIView] {
    
        var output: [UIView] = []
        output.append(self)
    
        for subview in self.subviews {
            output += subview.subviewsFlattened()
        }
    
        return output
    }

}

And then you can call it on any view:

let allViews = someView.subviewsFlattened()