ios - 如何在Swift中将特定的CGPoint设置为UIImageView的中心？

我有一个特定的cg点，我希望我的UIImageView以它为中心。我不知道怎么做。以下是我的尝试：

var firstDotView: UIView?
let dotSize: CGFloat = 20
@IBOutlet weak var imgPreViewOutlet: UIImageView!

override func viewDidLoad(){

    firstDotView = UIView.init()
    firstDotView?.frame = CGRect.init(x: 60, y: 60, width: dotSize, height: dotSize)
    firstDotView?.center = CGPoint.init(x: 60, y: 60)

    drawFirstDot()
    imgPreViewOutlet.addSubview(firstDotView!)

}


// DRAW ROUND CIRCLE
func drawFirstDot() -> Void {
    let layer = CAShapeLayer.init()
    layer.path = UIBezierPath.init(roundedRect: firstDotView!.bounds, cornerRadius: 50).cgPath
    layer.fillColor = UIColor.blue.cgColor
    layer.backgroundColor = UIColor.yellow.cgColor
    firstDotView?.layer.addSublayer(layer)
}

最佳答案

就这样做吧。

override func viewDidLayoutSubviews() {
    super.viewDidLayoutSubviews()
    let firstDotView = UIView(frame: CGRect(x: imgPreViewOutlet.bounds.width/2 - dotSize/2,
                                            y: imgPreViewOutlet.bounds.height/2 - dotSize/2,
                                            width: dotSize,
                                            height: dotSize))
    firstDotView.layer.cornerRadius  = dotSize/2
    firstDotView.backgroundColor = UIColor.yellow
    firstDotView.translatesAutoresizingMaskIntoConstraints = false
    imgPreViewOutlet.addSubview(firstDotView)
}