Merge pull request #1204 from Automattic/charlie/1187-window-animation

Magic Links: Fix window resizing animation + some clean up

Simplenote/SPNavigationController.swift

@@ -14,6 +14,11 @@ class SPNavigationController: NSViewController {
     var topViewController: NSViewController? {
         viewStack.last
     }
+
+    private var heightConstraint: NSLayoutConstraint!
+    private var totalTopPadding: CGFloat {
+        Constants.buttonViewTopPadding + Constants.buttonViewHeight
+    }
 
     init(initialViewController: NSViewController) {
         super.init(nibName: nil, bundle: nil)
@@ -24,33 +29,29 @@ class SPNavigationController: NSViewController {
     required init?(coder: NSCoder) {
         fatalError("init(coder:) has not been implemented")
     }
-
+    
     override func loadView() {
         guard let initialViewController = topViewController else {
             fatalError()
         }
 
         view = NSView()
+        heightConstraint = view.heightAnchor.constraint(equalToConstant: .zero)
         let initialView = initialViewController.view
         backButton = insertBackButton()
 
         view.translatesAutoresizingMaskIntoConstraints = false
         initialView.translatesAutoresizingMaskIntoConstraints = false
 
-        view.addSubview(initialView)
-
-        /// "Hint" we wanna occupy as little as possible. This constraint is meant to be broken, but the layout system will
-        /// attempt to reduce the Height, when possible
-        ///
-        let minimumHeightConstraint = view.heightAnchor.constraint(equalToConstant: .zero)
-        minimumHeightConstraint.priority = .init(1)
+        attachView(subview: initialViewController.view, below: nil)
+        resizeWindow(to: initialViewController.view, animated: false)
 
         NSLayoutConstraint.activate([
             initialView.leadingAnchor.constraint(equalTo: view.leadingAnchor),
             initialView.trailingAnchor.constraint(equalTo: view.trailingAnchor),
             initialView.topAnchor.constraint(equalTo: backButton.bottomAnchor),
             initialView.bottomAnchor.constraint(equalTo: view.bottomAnchor),
-            minimumHeightConstraint
+            heightConstraint
         ])
     }
 
@@ -71,10 +72,10 @@ class SPNavigationController: NSViewController {
 
         view.addSubview(backButton)
         NSLayoutConstraint.activate([
-            backButton.leadingAnchor.constraint(equalTo: view.leadingAnchor, constant: 10),
-            backButton.topAnchor.constraint(equalTo: view.topAnchor, constant: 30),
-            backButton.widthAnchor.constraint(equalToConstant: 50),
-            backButton.heightAnchor.constraint(equalToConstant: 30)
+            backButton.leadingAnchor.constraint(equalTo: view.leadingAnchor, constant: Constants.buttonViewLeadingPadding),
+            backButton.topAnchor.constraint(equalTo: view.topAnchor, constant: Constants.buttonViewTopPadding),
+            backButton.widthAnchor.constraint(equalToConstant: Constants.buttonViewWidth),
+            backButton.heightAnchor.constraint(equalToConstant: Constants.buttonViewHeight)
         ])
 
         return button
@@ -91,25 +92,15 @@ class SPNavigationController: NSViewController {
         let currentView = topViewController?.view
 
         attach(child: viewController)
-
-        /// Disable Bottom Constraint
-        /// This allows for the enclosing NSWindow to resize, just enough to fit the `nextViewController.view`
-        ///
-        if let currentView, let bottomConstraint = view.firstContraint(firstView: currentView, firstAttribute: .bottom) {
-            bottomConstraint.isActive = false
-        }
-
-        guard let (leadingAnchor, trailingAnchor) = attachView(subview: viewController.view, below: currentView) else {
-            return
-        }
+        attachView(subview: viewController.view, below: currentView)
+        resizeWindow(to: viewController.view, animated: animated)
 
         guard animated else {
+            currentView?.removeFromSuperview()
+            backButton.isHidden = hideBackButton
             return
         }
 
-        leadingAnchor.constant = view.frame.width
-        trailingAnchor.constant = view.frame.width
-
         animateTransition(slidingView: viewController.view, fadingView: currentView, direction: .trailingToLeading) {
             currentView?.removeFromSuperview()
         }
@@ -120,45 +111,53 @@ class SPNavigationController: NSViewController {
         viewStack.append(child)
     }
 
-    @discardableResult
-    private func attachView(subview: NSView, below siblingView: NSView?) -> (leading: NSLayoutConstraint, trailing: NSLayoutConstraint)? {
+    private func attachView(subview: NSView, below siblingView: NSView?) {
+        subview.translatesAutoresizingMaskIntoConstraints = false
+
         if let siblingView {
             view.addSubview(subview, positioned: .below, relativeTo: siblingView)
         } else {
             view.addSubview(subview)
         }
 
-        subview.translatesAutoresizingMaskIntoConstraints = false
-
-        let leadingAnchor = subview.leadingAnchor.constraint(equalTo: view.leadingAnchor)
-        let trailingAnchor = subview.trailingAnchor.constraint(equalTo: view.trailingAnchor)
-
         NSLayoutConstraint.activate([
-            leadingAnchor,
-            trailingAnchor,
-            subview.topAnchor.constraint(equalTo: backButton.bottomAnchor),
-            subview.bottomAnchor.constraint(equalTo: view.bottomAnchor)
+            subview.leadingAnchor.constraint(equalTo: view.leadingAnchor),
+            subview.trailingAnchor.constraint(equalTo: view.trailingAnchor),
+            subview.topAnchor.constraint(equalTo: backButton.bottomAnchor)
         ])
+    }
+
+    private func resizeWindow(to subview: NSView, animated: Bool) {
+        let finalHeight = subview.fittingSize.height + totalTopPadding
 
+        guard animated else {
+            heightConstraint.constant = finalHeight
+            return
+        }
 
-        return (leading: leadingAnchor, trailing: trailingAnchor)
+        NSAnimationContext.runAnimationGroup { context in
+            context.duration = 0.4
+            context.timingFunction = .init(name: .easeInEaseOut)
+
+            heightConstraint.animator().constant = finalHeight
+        }
     }
 
     // MARK: - Remove view from stack
-    func popViewController() {
+    func popViewController(animated: Bool = true) {
         guard viewStack.count > 1, let currentViewController = viewStack.popLast(), let nextViewController = viewStack.last else {
             return
         }
-
-        /// Disable Bottom Constraint
-        /// This allows for the enclosing NSWindow to resize, just enough to fit the `nextViewController.view`
-        ///
-        if let currentBottomConstraint = view.firstContraint(firstView: currentViewController.view, firstAttribute: .bottom) {
-            currentBottomConstraint.isActive = false
-        }
 
         attachView(subview: nextViewController.view, below: currentViewController.view)
-
+        resizeWindow(to: nextViewController.view, animated: animated)
+
+        guard animated else {
+            dettach(child: currentViewController)
+            backButton.isHidden = hideBackButton
+            return
+        }
+
         animateTransition(slidingView: currentViewController.view, fadingView: nextViewController.view, direction: .leadingToTrailing) {
             self.dettach(child: currentViewController)
         }
@@ -182,9 +181,14 @@ class SPNavigationController: NSViewController {
             return
         }
 
+        if direction == .trailingToLeading {
+            leadingConstraint.constant = view.frame.width
+            trailingConstraint.constant = view.frame.width
+        }
+
         let multiplier: CGFloat = direction == .leadingToTrailing ? 1 : -1
         let alpha: CGFloat = direction == .leadingToTrailing ? 1 : 0
-
+        
         NSAnimationContext.runAnimationGroup { context in
             context.duration = 0.4
             context.timingFunction = .init(name: .easeInEaseOut)
@@ -210,3 +214,10 @@ extension SPNavigationController {
         backButton.layer?.backgroundColor = .clear
     }
 }
+
+private struct Constants {
+    static let buttonViewWidth = CGFloat(50)
+    static let buttonViewHeight = CGFloat(30)
+    static let buttonViewTopPadding = CGFloat(30)
+    static let buttonViewLeadingPadding = CGFloat(10)
+}