CAShapelayer not showing - swift

Question

I've been trying to add a layer to my views and buttons but somehow the layer isn't appearing at all. What am I missing?
class ViewController: UIViewController {
var button1: CustomButton!
override func viewDidLoad() {
super.viewDidLoad()
button1 = CustomButton(frame: CGRectZero)
let views1 = ["button1": button1]
button1.backgroundColor = .clearColor()
view.addSubview(button1)
view.addConstraints(NSLayoutConstraint.constraintsWithVisualFormat("H:|-50-[button1(50)]", options: [], metrics: nil, views: views1))
view.addConstraints(NSLayoutConstraint.constraintsWithVisualFormat("V:[button1(50)]-50-|", options: [], metrics: nil, views: views1))
}
}
class CustomButton: UIButton {
let shape = CAShapeLayer()
override init(frame: CGRect) {
super.init(frame: frame)
translatesAutoresizingMaskIntoConstraints = false
shape.fillColor = UIColor.redColor().CGColor
shape.strokeColor = UIColor.blackColor().CGColor
shape.lineWidth = 0.5
shape.bounds = CGRect(x: 0, y: 0, width: 50, height: 50)
layer.insertSublayer(shape, atIndex: 0)
}
required init?(coder aDecoder: NSCoder) {
fatalError("init(coder:) has not been implemented")
}
override func layoutSubviews() {
super.layoutSubviews()
let padding: CGFloat = 10
let x = frame.origin.x - padding
let y = frame.origin.y - padding
let widths = bounds.width + 2 * padding
let height = bounds.height + 2 * padding
let rect = CGRect(x: x, y: y, width: widths, height: height)
shape.frame = rect
shape.path = UIBezierPath(rect: rect).CGPath
}
}
The button is added to the view without problems but nothing of the layer seems visible (been trying to change colors when tapped etc as well, setting the position or just edit the layer itself without adding a new one).

Answer 1

You missed '|' in your constraint string. Please update as,
view.addConstraints(NSLayoutConstraint.constraintsWithVisualFormat("H:|-50-[button1(50)]|", options: [], metrics: nil, views: views1))
view.addConstraints(NSLayoutConstraint.constraintsWithVisualFormat("V:|[button1(50)]-50-|", options: [], metrics: nil, views: views1))