Here is a quick example showing how to tie in a Swift enum with a UI control. In this case, the UI control is a UISegmentedControl that is used for switching a UIStackView in my UI between all of the UIStackViewDistribution types. The UIStackViewDistribution enum is currently:

enum UIStackViewDistribution : Int {
    case Fill
    case FillEqually
    case FillProportionally
    case EqualSpacing
    case EqualCentering
}

The key here is to name the segment titles of the segmented control in the same order according to the enum. So the title for segment 0 is "Fill", the title for segment 1 is "FillEqually", etc. Each time I select a segment, the stack view needs to change it's distribution property accordingly.

I have an IBAction wired up for every time a segment gets selected:

@IBAction private func segmentedControlChanged(sender: UISegmentedControl) {
    // TODO: Handle sender.selectedSegmentIndex here
    // self.stackView.distribution = get distribution
}

The distribution can be created using the rawValue of the enum. The UIStackViewDistribution enum has a rawValue of type Int, so here I used the selectedSegmentIndex for that parameter:

@IBAction private func segmentedControlChanged(sender: UISegmentedControl) {
    let distribution = UIStackViewDistribution(rawValue: sender.selectedSegmentIndex)

    // TODO: set self.stackView.distribution here
}

Initializing an enum with a rawValue will return an optional so it needs to be unwrapped first:

@IBAction private func segmentedControlChanged(sender: UISegmentedControl) {
    guard let distribution = UIStackViewDistribution(rawValue: sender.selectedSegmentIndex) else {
        return
    }

    // TODO: set self.stackView.distribution here
}

Finally, set the distribution on the stackView:

@IBAction private func segmentedControlChanged(sender: UISegmentedControl) {
    guard let distribution = UIStackViewDistribution(rawValue: sender.selectedSegmentIndex) else {
        return
    }

    UIView.animateWithDuration(0.5) {
        self.stackView.distribution = distribution
    }
}