Create a SlidingModalPresenter that allows to present custom modal view controller or view in a card with a sliding transition.

Riot/Modules/Modal/SlidingModalPresentationController.swift

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+/*
+ Copyright 2019 New Vector Ltd
+ 
+ Licensed under the Apache License, Version 2.0 (the "License");
+ you may not use this file except in compliance with the License.
+ You may obtain a copy of the License at
+ 
+ http://www.apache.org/licenses/LICENSE-2.0
+ 
+ Unless required by applicable law or agreed to in writing, software
+ distributed under the License is distributed on an "AS IS" BASIS,
+ WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ See the License for the specific language governing permissions and
+ limitations under the License.
+ */
+
+import UIKit
+
+/// `SlidingModalPresentationController` handles sliding transition presentation life cycle.
+final class SlidingModalPresentationController: UIPresentationController {
+    
+    // MARK: - Properties
+    
+    private var slidingModalContainerView: SlidingModalContainerView? {
+        return self.containerView?.subviews.first(where: { (view) -> Bool in
+            view is SlidingModalContainerView
+        }) as? SlidingModalContainerView
+    }
+    
+    // MARK: - Setup
+    
+    override init(presentedViewController: UIViewController, presenting presentingViewController: UIViewController?) {
+        super.init(presentedViewController: presentedViewController, presenting: presentingViewController)
+    }
+    
+    // MARK: - Life cycle
+    
+    override func viewWillTransition(to size: CGSize, with coordinator: UIViewControllerTransitionCoordinator) {
+        super.viewWillTransition(to: size, with: coordinator)
+        
+        if let slidingModalPresentable = self.presentedViewController as? SlidingModalPresentable, let slidingModalContainerView = self.slidingModalContainerView {
+            
+            let slidingModalContainerViewContentViewWidth = slidingModalContainerView.contentViewWidthFittingSize(size)
+            
+            let presentableHeight = slidingModalPresentable.layoutHeightFittingWidth(slidingModalContainerViewContentViewWidth)
+            slidingModalContainerView.updateContentViewMaxHeight(presentableHeight)
+        }
+        
+        coordinator.animate(alongsideTransition: { (UIViewControllerTransitionCoordinatorContext) -> Void in
+            self.slidingModalContainerView?.updateContentViewLayout()
+        }, completion: { _ in
+            
+        })
+    }
+    
+    override func presentationTransitionWillBegin() {
+        guard let coordinator = presentedViewController.transitionCoordinator else {
+            return
+        }
+        
+        coordinator.animate(alongsideTransition: { [weak self] _ in
+            // Update status bar appearance of presented view controller (if presenting view controller allowed it, see `modalPresentationCapturesStatusBarAppearance` property)
+            self?.presentedViewController.setNeedsStatusBarAppearanceUpdate()
+        }, completion: nil)
+    }
+    
+    override func presentationTransitionDidEnd(_ completed: Bool) {
+        self.slidingModalContainerView?.delegate = self
+    }
+    
+    override func dismissalTransitionWillBegin() {
+        guard let coordinator = presentedViewController.transitionCoordinator else {
+            return
+        }
+
+        coordinator.animate(alongsideTransition: { [weak self] _ -> Void in
+            // Update status bar appearance of presenting view controller
+            self?.presentingViewController.setNeedsStatusBarAppearanceUpdate()
+        }, completion: nil)
+    }
+    
+    override func dismissalTransitionDidEnd(_ completed: Bool) {
+        if completed {
+            self.slidingModalContainerView?.removeFromSuperview()
+        }
+    }
+}
+
+// MARK: - SlidingModalContainerViewDelegate
+extension SlidingModalPresentationController: SlidingModalContainerViewDelegate {
+    
+    func slidingModalContainerViewDidTapBackground(_ view: SlidingModalContainerView) {
+        
+        let isDismissOnBackgroundTapAllowed: Bool
+        
+        if let slidingModalPresentable = self.presentedViewController as? SlidingModalPresentable {
+            isDismissOnBackgroundTapAllowed = slidingModalPresentable.allowsDismissOnBackgroundTap()
+        } else {
+            isDismissOnBackgroundTapAllowed = true
+        }
+        
+        if isDismissOnBackgroundTapAllowed {
+            self.presentedViewController.dismiss(animated: true, completion: nil)
+        }
+    }
+}