Merge pull request #47 from zenangst/feature/animations-on-mac-os

Implement support for animated injections on macOS

Source/iOS+tvOS/UIViewController+Extensions.swift

@@ -1,51 +1,6 @@
 import UIKit
 
 @objc public extension UIViewController {
-  /// Removes all child view controllers.
-  private func removeChildViewControllers() {
-    #if swift(>=4.2)
-    children.forEach { controller in
-      controller.willMove(toParent: nil)
-      controller.view.removeFromSuperview()
-      controller.removeFromParent()
-    }
-    #else
-    childViewControllers.forEach { controller in
-      controller.willMove(toParentViewController: nil)
-      controller.view.removeFromSuperview()
-      controller.removeFromParentViewController()
-    }
-    #endif
-  }
-
-  /// Lock screen updates using a `CATransaction`.
-  ///
-  /// - Parameter shouldLock: A boolean value indicating if the method should
-  ///                         be invoked or not. This is determined by the
-  ///                         amount of child view controllers in the controller.
-  private func lockScreenUpdates(_ shouldLock: Bool) {
-    guard shouldLock else { return }
-    CATransaction.begin()
-    CATransaction.lock()
-  }
-
-  /// Unlock screen updates using a `CATransaction`.
-  ///
-  /// - Parameters:
-  /// - Parameter shouldLock: A boolean value indicating if the method should
-  ///                         be invoked or not. This is determined by the
-  ///                         amount of child view controllers in the controller.
-  ///   - scrollViews: A dictionary of scroll views related to the view controller.
-  private func unlockScreenUpdates(_ shouldUnlock: Bool, scrollViews: [UIScrollView]) {
-    guard shouldUnlock else { return }
-    syncOldScrollViews(scrollViews, with: indexScrollViews())
-    let nearFuture = DispatchTime.now() + 0.3
-    DispatchQueue.main.asyncAfter(deadline: nearFuture) {
-      CATransaction.unlock()
-      CATransaction.commit()
-    }
-  }
-
   /// Validate if the current class was injected by checking the contents
   /// of the notification.
   ///
@@ -60,28 +15,15 @@ import UIKit
     performInjection()
   }
 
-  /// Clean up view hierarchy by removing child view controllers, view and layers.
-  private func performCleanUp() {
-    switch self {
-    case _ as UINavigationController:
-      break
-    case let tabBarController as UITabBarController:
-      tabBarController.setViewControllers([], animated: true)
-    default:
-      removeChildViewControllers()
-      removeViewsAndLayers()
-    }
-  }
-
   /// Invoke all injection related methods in sequence.
   /// If this method is invoked with animations enabled,
   /// a snapshot of the current view will be created and
   /// added to the applications window in order to nicely
   /// transition to the new controller view state.
   private func performInjection() {
     let options: UIView.AnimationOptions = [.allowAnimatedContent,
-                                           .beginFromCurrentState,
-                                           .layoutSubviews]
+                                            .beginFromCurrentState,
+                                            .layoutSubviews]
     if Injection.animations, let snapshot = self.view.snapshotView(afterScreenUpdates: false) {
       let maskView = UIView()
       maskView.frame.size = snapshot.frame.size
@@ -90,8 +32,8 @@ import UIKit
       snapshot.mask = maskView
       view.window?.addSubview(snapshot)
       let oldScrollViews = indexScrollViews()
-      performCleanUp()
-      reloadUserInterface()
+      resetViewControllerState()
+      rebuildViewContorllerState()
       syncOldScrollViews(oldScrollViews, with: indexScrollViews())
       UIView.animate(withDuration: 0.25, delay: 0.0, options: options, animations: {
         snapshot.alpha = 0.0
@@ -101,32 +43,16 @@ import UIKit
     } else {
       let scrollViews = indexScrollViews()
       lockScreenUpdates(!scrollViews.isEmpty)
-      performCleanUp()
-      reloadUserInterface()
+      resetViewControllerState()
+      rebuildViewContorllerState()
       unlockScreenUpdates(!scrollViews.isEmpty, scrollViews: scrollViews)
     }
   }
 
-  /// Sync two scroll views content offset if they are of the same type.
-  ///
-  /// - Parameters:
-  ///   - oldScrollViews: An array of scroll views from before the injection occured.
-  ///   - newScrollViews: An array of new scroll views after the injection occured.
-  private func syncOldScrollViews(_ oldScrollViews: [UIScrollView], with newScrollViews: [UIScrollView]) {
-    for (offset, scrollView) in newScrollViews.enumerated() {
-      if offset < oldScrollViews.count {
-        let oldScrollView = oldScrollViews[offset]
-        if type(of: scrollView) == type(of: oldScrollView) {
-          scrollView.contentOffset = oldScrollView.contentOffset
-        }
-      }
-    }
-  }
-
   /// Will invoke `viewDidLoad` to run view controllers setup operations.
   /// In addition, it will force all subview to layout and collection & table views
   /// to reload. This is to make sure that we are displaying the latest changes.
-  private func reloadUserInterface() {
+  private func rebuildViewContorllerState() {
     viewDidLoad()
     view.subviews.forEach { view in
       view.setNeedsLayout()
@@ -142,6 +68,34 @@ import UIKit
     }
   }
 
+  /// Lock screen updates using a `CATransaction`.
+  ///
+  /// - Parameter shouldLock: A boolean value indicating if the method should
+  ///                         be invoked or not. This is determined by the
+  ///                         amount of child view controllers in the controller.
+  private func lockScreenUpdates(_ shouldLock: Bool) {
+    guard shouldLock else { return }
+    CATransaction.begin()
+    CATransaction.lock()
+  }
+
+  /// Unlock screen updates using a `CATransaction`.
+  ///
+  /// - Parameters:
+  /// - Parameter shouldLock: A boolean value indicating if the method should
+  ///                         be invoked or not. This is determined by the
+  ///                         amount of child view controllers in the controller.
+  ///   - scrollViews: A dictionary of scroll views related to the view controller.
+  private func unlockScreenUpdates(_ shouldUnlock: Bool, scrollViews: [UIScrollView]) {
+    guard shouldUnlock else { return }
+    syncOldScrollViews(scrollViews, with: indexScrollViews())
+    let nearFuture = DispatchTime.now() + 0.3
+    DispatchQueue.main.asyncAfter(deadline: nearFuture) {
+      CATransaction.unlock()
+      CATransaction.commit()
+    }
+  }
+
   /// Create an index of the content offsets for all underlying scroll views.
   ///
   /// - Returns: A dictionary of scroll views and their current origin.
@@ -166,6 +120,52 @@ import UIKit
     return scrollViews
   }
 
+  /// Sync two scroll views content offset if they are of the same type.
+  ///
+  /// - Parameters:
+  ///   - oldScrollViews: An array of scroll views from before the injection occured.
+  ///   - newScrollViews: An array of new scroll views after the injection occured.
+  private func syncOldScrollViews(_ oldScrollViews: [UIScrollView], with newScrollViews: [UIScrollView]) {
+    for (offset, scrollView) in newScrollViews.enumerated() {
+      if offset < oldScrollViews.count {
+        let oldScrollView = oldScrollViews[offset]
+        if type(of: scrollView) == type(of: oldScrollView) {
+          scrollView.contentOffset = oldScrollView.contentOffset
+        }
+      }
+    }
+  }
+
+  /// Removes all child view controllers.
+  private func removeChildViewControllers() {
+    #if swift(>=4.2)
+    children.forEach { controller in
+      controller.willMove(toParent: nil)
+      controller.view.removeFromSuperview()
+      controller.removeFromParent()
+    }
+    #else
+    childViewControllers.forEach { controller in
+      controller.willMove(toParentViewController: nil)
+      controller.view.removeFromSuperview()
+      controller.removeFromParentViewController()
+    }
+    #endif
+  }
+
+  /// Clean up view hierarchy by removing child view controllers, view and layers.
+  private func resetViewControllerState() {
+    switch self {
+    case _ as UINavigationController:
+      break
+    case let tabBarController as UITabBarController:
+      tabBarController.setViewControllers([], animated: true)
+    default:
+      removeChildViewControllers()
+      removeViewsAndLayers()
+    }
+  }
+
   /// Removes all views and layers from a view.
   private func removeViewsAndLayers() {
     view.subviews.forEach {