Fix key commands not working inside split nav controller on iPad

Fixes #179

Tusker/Screens/Main/MainSplitViewController.swift

@@ -20,9 +20,6 @@ class MainSplitViewController: UISplitViewController {
     
     private var tabBarViewController: MainTabBarViewController!
     
-//    private var secondaryNavController: UINavigationController! {
-//        viewController(for: .secondary) as? UINavigationController
-//    }
     private var secondaryNavController: SplitNavigationController! {
         viewController(for: .secondary) as? SplitNavigationController
     }
@@ -49,8 +46,6 @@ class MainSplitViewController: UISplitViewController {
         setViewController(sidebar, for: .primary)
         primaryBackgroundStyle = .sidebar
 
-//        let secondaryNav = EnhancedNavigationViewController()
-//        secondaryNav.useBrowserStyleNavigation = true
         let splitNav = SplitNavigationController()
         setViewController(splitNav, for: .secondary)
         // don't unnecesarily construct a content VC unless the we're in actually split mode

Tusker/Screens/Utilities/SplitNavigationController.swift

@@ -60,6 +60,7 @@ class SplitNavigationController: UIViewController {
                 self.rootNav.pushViewController(vc, animated: true)
             }
         }
+        secondaryNav.owner = self
         secondaryNav.closeSecondaryImpl = { [unowned self] in
             self.popToRootViewController(animated: true)
         }
@@ -72,26 +73,19 @@ class SplitNavigationController: UIViewController {
         // it needs a UINavigationController to be this VC's first child, otherwise it will embed this VC inside
         // yet another UINavigationController, which can then cause a crash when we try to embed a nav controller inside
         // of ourself (because nested nav controllers are forbidden)
-        rootNav.willMove(toParent: self)
-        addChild(rootNav)
-        rootNav.didMove(toParent: self)
-        secondaryNav.willMove(toParent: self)
-        addChild(secondaryNav)
-        secondaryNav.didMove(toParent: self)
-    }
-    
-    required init?(coder: NSCoder) {
-        fatalError("init(coder:) has not been implemented")
-    }
-    
-    override func viewDidLoad() {
-        super.viewDidLoad()
+        // and because of that, the view needs to be added here, in between the addChild/didMove(toParent:) calls
+        // and so the view needs to be loaded immediately
+        loadViewIfNeeded()
         
+        addChild(rootNav)
         rootNav.view.translatesAutoresizingMaskIntoConstraints = false
         view.addSubview(rootNav.view)
+        rootNav.didMove(toParent: self)
+        addChild(secondaryNav)
         secondaryNav.view.translatesAutoresizingMaskIntoConstraints = false
         view.addSubview(secondaryNav.view)
-
+        secondaryNav.didMove(toParent: self)
+        
         separatorView.backgroundColor = .separator
         separatorView.translatesAutoresizingMaskIntoConstraints = false
         view.addSubview(separatorView)
@@ -110,10 +104,20 @@ class SplitNavigationController: UIViewController {
             secondaryNav.view.bottomAnchor.constraint(equalTo: view.bottomAnchor),
             secondaryNav.view.leadingAnchor.constraint(equalTo: separatorView.trailingAnchor),
         ])
-
+        
         updateSecondaryNavVisibility()
     }
     
+    required init?(coder: NSCoder) {
+        fatalError("init(coder:) has not been implemented")
+    }
+    
+    override func viewDidLoad() {
+        super.viewDidLoad()
+
+        // NOTE: as explained by the large comment above, viewDidLoad is called during initialization, and so things may not be fully setup when it is
+    }
+    
     override func show(_ vc: UIViewController, sender: Any?) {
         if !canShowSecondaryNav {
             rootNav.pushViewController(vc, animated: true)
@@ -247,6 +251,7 @@ private class SplitRootNavigationController: UINavigationController {
 }
 
 private class SplitSecondaryNavigationController: EnhancedNavigationViewController {
+    fileprivate unowned var owner: SplitNavigationController!
     fileprivate var closeSecondaryImpl: (() -> Void)!
     
     override var viewControllers: [UIViewController] {
@@ -257,6 +262,12 @@ private class SplitSecondaryNavigationController: EnhancedNavigationViewControll
         }
     }
     
+    override var next: UIResponder? {
+        // ordinarily, the next responder in the chain would be the SplitNavigationController's view
+        // but that would bypass the VC in the root nav, so we reroute the repsonder chain to include it
+        owner.viewControllers.first!.view
+    }
+    
     private func configureSecondarySplitCloseButton(for viewController: UIViewController) {
         guard viewController.navigationItem.leftBarButtonItem?.tag != ViewTags.splitNavCloseSecondaryButton else {
             return