UINavigationController-Alike for Desktop-Cocoa?

Question

I\'m currently developing an application with an user interface much like Twitter for Mac (Pushing in/out of views like on iOS).

Has anyone implemented a UIViewCont

Answer 1

Here how we did NavigationController, without navigation bar. Implementing navigation bar with transitions between navigation items similar to how transition between views made in example below.

import AppKit

public class NavigationController: NSViewController {

   public private (set) var viewControllers: [NSViewController] = []

   open override func loadView() {
      view = NSView()
      view.wantsLayer = true
   }

   public init(rootViewController: NSViewController) {
      super.init(nibName: nil, bundle: nil)
      pushViewController(rootViewController, animated: false)
   }

   public required init?(coder: NSCoder) {
      fatalError()
   }
}

extension NavigationController {

   public var topViewController: NSViewController? {
      return viewControllers.last
   }

   public func pushViewControllerAnimated(_ viewController: NSViewController) {
      pushViewController(viewController, animated: true)
   }

   public func pushViewController(_ viewController: NSViewController, animated: Bool) {
      viewController.navigationController = self
      viewController.view.wantsLayer = true
      if animated, let oldVC = topViewController {
         embedChildViewController(viewController)
         let endFrame = oldVC.view.frame
         let startFrame = endFrame.offsetBy(dx: endFrame.width, dy: 0)
         viewController.view.frame = startFrame
         viewController.view.alphaValue = 0.85
         viewControllers.append(viewController)
         NSAnimationContext.runAnimationGroup({ context in
            context.duration = 0.2
            context.allowsImplicitAnimation = true
            context.timingFunction = .easeOut
            viewController.view.animator().frame = endFrame
            viewController.view.animator().alphaValue = 1
            oldVC.view.animator().alphaValue = 0.25
         }) {
            oldVC.view.alphaValue = 1
            oldVC.view.removeFromSuperview()
         }
      } else {
         embedChildViewController(viewController)
         viewControllers.append(viewController)
      }
   }

   @discardableResult
   public func popViewControllerAnimated() -> NSViewController? {
      return popViewController(animated: true)
   }

   @discardableResult
   public func popViewController(animated: Bool) -> NSViewController? {
      guard let oldVC = viewControllers.popLast() else {
         return nil
      }

      if animated, let newVC = topViewController {
         let endFrame = oldVC.view.frame.offsetBy(dx: oldVC.view.frame.width, dy: 0)
         view.addSubview(newVC.view, positioned: .below, relativeTo: oldVC.view)
         NSAnimationContext.runAnimationGroup({ context in
            context.duration = 0.23
            context.allowsImplicitAnimation = true
            context.timingFunction = .easeIn
            oldVC.view.animator().frame = endFrame
            oldVC.view.animator().alphaValue = 0.85
         }) {
            self.unembedChildViewController(oldVC)
         }
      } else {
         unembedChildViewController(oldVC)
      }
      return oldVC
   }

}

Reusable extensions:

extension NSViewController {

   private struct OBJCAssociationKey {
      static var navigationController = "com.mc.navigationController"
   }

   public var navigationController: NavigationController? {
      get {
         return ObjCAssociation.value(from: self, forKey: &OBJCAssociationKey.navigationController)
      } set {
         ObjCAssociation.setAssign(value: newValue, to: self, forKey: &OBJCAssociationKey.navigationController)
      }
   }
}

extension NSViewController {

   public func embedChildViewController(_ vc: NSViewController, container: NSView? = nil) {
      addChildViewController(vc)
      vc.view.frame = CGRect(x: 0, y: 0, width: view.frame.width, height: view.frame.height)
      vc.view.autoresizingMask = [.height, .width]
      (container ?? view).addSubview(vc.view)
   }

   public func unembedChildViewController(_ vc: NSViewController) {
      vc.view.removeFromSuperview()
      vc.removeFromParentViewController()
   }
}

struct ObjCAssociation {

   static func value(from object: AnyObject, forKey key: UnsafeRawPointer) -> T? {
      return objc_getAssociatedObject(object, key) as? T
   }

   static func setAssign(value: T?, to object: Any, forKey key: UnsafeRawPointer) {
      objc_setAssociatedObject(object, key, value, .OBJC_ASSOCIATION_ASSIGN)
   }

   static func setRetainNonAtomic(value: T?, to object: Any, forKey key: UnsafeRawPointer) {
      objc_setAssociatedObject(object, key, value, .OBJC_ASSOCIATION_RETAIN_NONATOMIC)
   }

   static func setCopyNonAtomic(value: T?, to object: Any, forKey key: UnsafeRawPointer) {
      objc_setAssociatedObject(object, key, value, .OBJC_ASSOCIATION_COPY_NONATOMIC)
   }

   static func setRetain(value: T?, to object: Any, forKey key: UnsafeRawPointer) {
      objc_setAssociatedObject(object, key, value, .OBJC_ASSOCIATION_RETAIN)
   }

   static func setCopy(value: T?, to object: Any, forKey key: UnsafeRawPointer) {
      objc_setAssociatedObject(object, key, value, .OBJC_ASSOCIATION_COPY)
   }
}