How to change position of UIButton?

Question

Nothing happens but why ???

@IBOutlet weak var button10: UIButton!

override func viewDidLoad() {
    super.viewDidLoad()

    button10.center = CGPoint(x: self.view.frame.x/2, y: self.view.frame.y/2)

 }

Answer 1

Add constraints for center in view

var constX = NSLayoutConstraint(item: button10, attribute: NSLayoutAttribute.CenterX, relatedBy: NSLayoutRelation.Equal, toItem: view, attribute: NSLayoutAttribute.CenterX, multiplier: 1, constant: 0)
view.addConstraint(constX)

var constY = NSLayoutConstraint(item: button10, attribute: NSLayoutAttribute.CenterY, relatedBy: NSLayoutRelation.Equal, toItem: view, attribute: NSLayoutAttribute.CenterY, multiplier: 1, constant: 0)
view.addConstraint(constY)

Answer 2

As Ashhish said, add two constraints between the parent view and the button. But this can also be done using the awesome Github project Cartography:

layout(view, button) {
    parent, button in
    button.centerX == parent.centerX
    button.centerY == parent.centerY
}

Very neat!

You can include Cartography using Cocoapods.