タグ: AutoLayout

let constraints = [
    view.centerXAnchor.constraint(equalTo: superview.centerXAnchor),
    view.centerYAnchor.constraint(equalTo: superview.centerYAnchor),
    view.widthAnchor.constraint(equalToConstant: 100),
    view.heightAnchor.constraint(equalTo: view.widthAnchor)
]
NSLayoutConstraint.activate(constraints)

extension UIView {

    /* Constraint creation conveniences. See NSLayoutAnchor.h for details.
     */
    open var leadingAnchor: NSLayoutXAxisAnchor { get }

    open var trailingAnchor: NSLayoutXAxisAnchor { get }

    open var leftAnchor: NSLayoutXAxisAnchor { get }

    open var rightAnchor: NSLayoutXAxisAnchor { get }

    open var topAnchor: NSLayoutYAxisAnchor { get }

    open var bottomAnchor: NSLayoutYAxisAnchor { get }

    open var widthAnchor: NSLayoutDimension { get }

    open var heightAnchor: NSLayoutDimension { get }

    open var centerXAnchor: NSLayoutXAxisAnchor { get }

    open var centerYAnchor: NSLayoutYAxisAnchor { get }

    open var firstBaselineAnchor: NSLayoutYAxisAnchor { get }

    open var lastBaselineAnchor: NSLayoutYAxisAnchor { get }
}