An NSStackView extension for animated hiding/showing of views

NSStackView+Animations.swift

//
//  NSStackView+Animations.swift
//
//  Created by Martin Höller on 18.06.16.
//  Copyright © 2016 blue banana software. All rights reserved.
//
//  Based on http://prod.lists.apple.com/archives/cocoa-dev/2015/Jan/msg00314.html

import Cocoa

extension NSStackView {
    
    func hideViews(views: [NSView], animated: Bool) {
        views.forEach { view in
            view.hidden = true
        }
        
        if animated {
            NSAnimationContext.runAnimationGroup({ context in
                context.duration = 0.3
                context.allowsImplicitAnimation = true
                self.window?.layoutIfNeeded()
                
                }, completionHandler: nil)
        }
    }
    
    func showViews(views: [NSView], animated: Bool) {
        views.forEach { view in
            // unhide the view so the stack view knows how to layout…
            view.hidden = false
            
            if animated {
                view.wantsLayer = true
                // …but set opacity to 0 so the view is not visible during the animation
                view.layer!.opacity = 0.0
            }
        }
        
        if animated {
            NSAnimationContext.runAnimationGroup({ context in
                context.duration = 0.3
                context.allowsImplicitAnimation = true
                self.window?.layoutIfNeeded()
                
                }, completionHandler: {
                    // reset opacity to show the views after the animation finished
                    views.forEach { view in
                        view.layer!.opacity = 1.0
                    }
            })
        }
    }
}