how to use values returned by Swift function

Question

I am trying to use a Swift function to place a circle in the centre of a view so it is always on centre regardless of screen size. I can draw the circle at a point defined by a

Answer 1

First of all, UIViews have a center attribute, so you don't need to calculate it.

Second, the behavior may be inconsistent if changing it with viewDidLoad, and won't react to any changes to size/rotation.

I would recommend making a subClass of UIView that manages drawing the circle and doing something like this:

class ViewController: UIViewController {

    var circle: CircleView?

    override func viewWillAppear(_ animated: Bool) {
        super.viewWillAppear(animated)
        centerCircle()
    }

    override func viewDidLayoutSubviews() {
        super.viewDidLayoutSubviews()
        centerCircle()
    }

    func centerCircle() {
        circle?.center = self.view.center
    }
}