Boilerplate code example

override func viewDidLoad() {
    super.viewDidLoad()

    let myView = UIView()
    myView.backgroundColor = UIColor.blueColor()
    myView.translatesAutoresizingMaskIntoConstraints = false
    view.addSubview(myView)

    // Add constraints code here
    // ...
}

In the examples below the Anchor Style is the preferred method over NSLayoutConstraint Style, however it is only available from iOS 9, so if you are supporting iOS 8 then you should still use NSLayoutConstraint Style.

Pinning

Anchor Style

let margins = view.layoutMarginsGuide
myView.leadingAnchor.constraintEqualToAnchor(margins.leadingAnchor, constant: 20).active = true

• In addition to leadingAnchor, there is also trailingAnchor, topAnchor, and bottomAnchor.

NSLayoutConstraint Style

NSLayoutConstraint(item: myView, attribute: NSLayoutAttribute.Leading, relatedBy: NSLayoutRelation.Equal, toItem: view, attribute: NSLayoutAttribute.LeadingMargin, multiplier: 1.0, constant: 20.0).active = true

• In addition to .Leading there is also .Trailing, .Top, and .Bottom.
• In addition to .LeadingMargin there is also .TrailingMargin, .TopMargin, and .BottomMargin.

Visual Format Language style

NSLayoutConstraint.constraintsWithVisualFormat("H:|-20-[myViewKey]", options: [], metrics: nil, views: ["myViewKey": myView])

Width and Height

Anchor Style

myView.widthAnchor.constraintEqualToAnchor(nil, constant: 200).active = true
myView.heightAnchor.constraintEqualToAnchor(nil, constant: 100).active = true

NSLayoutConstraint Style

NSLayoutConstraint(item: myView, attribute: NSLayoutAttribute.Width, relatedBy: NSLayoutRelation.Equal, toItem: nil, attribute: NSLayoutAttribute.NotAnAttribute, multiplier: 1, constant: 200).active = true
NSLayoutConstraint(item: myView, attribute: NSLayoutAttribute.Height, relatedBy: NSLayoutRelation.Equal, toItem: nil, attribute: NSLayoutAttribute.NotAnAttribute, multiplier: 1, constant: 100).active = true

Visual Format Language style

NSLayoutConstraint.constraintsWithVisualFormat("H:[myViewKey(200)]", options: [], metrics: nil, views: ["myViewKey": myView])
NSLayoutConstraint.constraintsWithVisualFormat("V:[myViewKey(100)]", options: [], metrics: nil, views: ["myViewKey": myView])