SizeClassView.swift

import UIKit

class SizeClassView: UIView {

    private var regularHeightConstraints = [NSLayoutConstraint]()
    private var compactHeigthConstraints = [NSLayoutConstraint]()

    func addRegularHeightConstraint(regularHeightConstraint: NSLayoutConstraint) {
        regularHeightConstraints.append(regularHeightConstraint)
        addConstraint(regularHeightConstraint)
        regularHeightConstraint.active = false
    }

    func addRegularHeightConstraints(regularHeightConstraints: [NSLayoutConstraint]) {
        self.regularHeightConstraints.appendContentsOf(regularHeightConstraints)
        addConstraints(regularHeightConstraints)
        NSLayoutConstraint.deactivateConstraints(regularHeightConstraints)
    }

    func addCompactHeightConstraint(compactHeigthConstraint: NSLayoutConstraint) {
        compactHeigthConstraints.append(compactHeigthConstraint)
        addConstraint(compactHeigthConstraint)
        compactHeigthConstraint.active = false
    }

    func addCompactHeightConstraints(compactHeigthConstraints: [NSLayoutConstraint]) {
        self.compactHeigthConstraints.appendContentsOf(compactHeigthConstraints)
        addConstraints(compactHeigthConstraints)
        NSLayoutConstraint.deactivateConstraints(compactHeigthConstraints)
    }

    override func traitCollectionDidChange(previousTraitCollection: UITraitCollection?) {
        super.traitCollectionDidChange(previousTraitCollection)

        switch traitCollection.verticalSizeClass {
        case .Unspecified:
            break
        case .Regular:
            NSLayoutConstraint.deactivateConstraints(compactHeigthConstraints)
            NSLayoutConstraint.activateConstraints(regularHeightConstraints)
        case .Compact:
            NSLayoutConstraint.deactivateConstraints(regularHeightConstraints)
            NSLayoutConstraint.activateConstraints(compactHeigthConstraints)
        }
    }
}