Revert back to UIKit for the presentation of the timeline media preview. (#3719)

* Revert back to UIKit for the presentation of the timeline media preview. * Fix a presentation issue where the media is clipped until the animation finishes. * Workaround for the preview controller replacing the info button when swiping. * Use a self-sizing detent on the media info sheet.
2026-11-03 06:55:59 +00:00 · 2025-01-31 17:28:14 +00:00
parent ef340fb70f
commit 6cd583d904
25 changed files with 695 additions and 583 deletions
@@ -0,0 +1,188 @@
+//
+// Copyright 2022-2024 New Vector Ltd.
+//
+// SPDX-License-Identifier: AGPL-3.0-only OR LicenseRef-Element-Commercial
+// Please see LICENSE files in the repository root for full details.
+//
+
+import Combine
+import QuickLook
+import SwiftUI
+
+extension View {
+    /// Preview a media file using a QuickLook Preview Controller. The preview is interactive with
+    /// the dismiss gesture working as expected if it was presented from UIKit.
+    func timelineMediaPreview(viewModel: Binding<TimelineMediaPreviewViewModel?>) -> some View {
+        modifier(TimelineMediaPreviewModifier(viewModel: viewModel))
+    }
+}
+
+private struct TimelineMediaPreviewModifier: ViewModifier {
+    @Binding var viewModel: TimelineMediaPreviewViewModel?
+    
+    @State private var dismissalPublisher = PassthroughSubject<Void, Never>()
+    
+    func body(content: Content) -> some View {
+        content.background {
+            if let viewModel {
+                MediaPreviewViewController(viewModel: viewModel,
+                                           dismissalPublisher: dismissalPublisher) { self.viewModel = nil }
+                    .id(viewModel.instanceID) // Fixes a bug where opening a second preview too quickly can break presentation.
+            } else {
+                // Work around QLPreviewController dismissal issues, see below.
+                let _ = dismissalPublisher.send(())
+            }
+        }
+    }
+}
+
+private struct MediaPreviewViewController: UIViewControllerRepresentable {
+    let viewModel: TimelineMediaPreviewViewModel
+    let dismissalPublisher: PassthroughSubject<Void, Never>
+    let onDismiss: () -> Void
+
+    func makeUIViewController(context: Context) -> PreviewHostingController {
+        PreviewHostingController(viewModel: viewModel,
+                                 dismissalPublisher: dismissalPublisher,
+                                 onDismiss: onDismiss)
+    }
+
+    func updateUIViewController(_ uiViewController: PreviewHostingController, context: Context) { }
+    
+    /// A view controller that hosts the QuickLook preview.
+    ///
+    /// This wrapper somehow allows the preview controller to do presentation/dismissal
+    /// animations and interactions which don't work if you represent it directly to SwiftUI 🤷‍♂️
+    class PreviewHostingController: UIViewController, QLPreviewControllerDelegate {
+        let onDismiss: () -> Void
+        let sourceView = UIView()
+        
+        private let previewController: TimelineMediaPreviewController
+        private var hasBeenPresented = false
+        
+        private var dismissalObserver: AnyCancellable?
+        private var cancellables: Set<AnyCancellable> = []
+        
+        init(viewModel: TimelineMediaPreviewViewModel,
+             dismissalPublisher: PassthroughSubject<Void, Never>,
+             onDismiss: @escaping () -> Void) {
+            self.onDismiss = onDismiss
+            previewController = TimelineMediaPreviewController(context: viewModel.context)
+
+            super.init(nibName: nil, bundle: nil)
+            
+            // The QLPreviewController will not automatically dismiss itself when the underlying view is removed
+            // (e.g. switching rooms from a notification) and it continues to hold on to the whole hierarcy.
+            // Manually tell it to dismiss itself here.
+            dismissalObserver = dismissalPublisher.sink { [weak self] _ in
+                // Dispatching on main.async with weak self we avoid doing an extra dismiss if the view is presented on top of another modal
+                DispatchQueue.main.async { [weak self] in
+                    self?.dismiss(animated: true)
+                }
+            }
+        }
+        
+        @available(*, unavailable)
+        required init?(coder: NSCoder) {
+            fatalError("init(coder:) has not been implemented")
+        }
+        
+        override func viewDidLoad() {
+            view.backgroundColor = .clear
+            view.addSubview(sourceView)
+            
+            sourceView.translatesAutoresizingMaskIntoConstraints = false
+            NSLayoutConstraint.activate([
+                sourceView.centerXAnchor.constraint(equalTo: view.centerXAnchor),
+                sourceView.centerYAnchor.constraint(equalTo: view.bottomAnchor),
+                sourceView.widthAnchor.constraint(equalToConstant: 100),
+                sourceView.heightAnchor.constraint(equalToConstant: 100)
+            ])
+        }
+        
+        // Don't use viewWillAppear due to the following warning:
+        // Presenting view controller <QLPreviewController> from detached view controller <HostingController> is not supported,
+        // and may result in incorrect safe area insets and a corrupt root presentation. Make sure <HostingController> is in
+        // the view controller hierarchy before presenting from it. Will become a hard exception in a future release.
+        override func viewDidAppear(_ animated: Bool) {
+            super.viewDidAppear(animated)
+            
+            guard !hasBeenPresented else { return }
+            
+            previewController.delegate = self
+            
+            present(previewController, animated: true)
+            
+            hasBeenPresented = true
+        }
+        
+        // MARK: QLPreviewControllerDelegate
+        
+        func previewController(_ controller: QLPreviewController, editingModeFor previewItem: QLPreviewItem) -> QLPreviewItemEditingMode {
+            .disabled
+        }
+        
+        func previewController(_ controller: QLPreviewController, transitionViewFor item: any QLPreviewItem) -> UIView? {
+            sourceView
+        }
+        
+        func previewControllerDidDismiss(_ controller: QLPreviewController) {
+            onDismiss()
+        }
+    }
+}
+
+// MARK: - Previews
+
+struct TimelineMediaPreviewModifier_Previews: PreviewProvider {
+    static let viewModel = makeViewModel()
+    static let downloadingViewModel = makeViewModel(isDownloading: true)
+    static let downloadErrorViewModel = makeViewModel(isDownloadError: true)
+    
+    static var previews: some View {
+        MediaPreviewViewController(viewModel: viewModel, dismissalPublisher: .init()) { }
+            .previewDisplayName("Normal")
+        MediaPreviewViewController(viewModel: downloadingViewModel, dismissalPublisher: .init()) { }
+            .previewDisplayName("Downloading")
+        MediaPreviewViewController(viewModel: downloadErrorViewModel, dismissalPublisher: .init()) { }
+            .previewDisplayName("Download Error")
+    }
+    
+    static func makeViewModel(isDownloading: Bool = false, isDownloadError: Bool = false) -> TimelineMediaPreviewViewModel {
+        let item = FileRoomTimelineItem(id: .randomEvent,
+                                        timestamp: .mock,
+                                        isOutgoing: false,
+                                        isEditable: false,
+                                        canBeRepliedTo: true,
+                                        isThreaded: false,
+                                        sender: .init(id: "", displayName: "Sally Sanderson"),
+                                        content: .init(filename: "Important document.pdf",
+                                                       caption: "A caption goes right here.",
+                                                       source: try? .init(url: .mockMXCFile, mimeType: nil),
+                                                       fileSize: 3 * 1024 * 1024,
+                                                       thumbnailSource: nil,
+                                                       contentType: .pdf))
+        
+        let timelineController = MockRoomTimelineController(timelineKind: .media(.mediaFilesScreen))
+        timelineController.timelineItems = [item]
+        
+        let mediaProvider = MediaProviderMock(configuration: .init())
+        
+        if isDownloading {
+            mediaProvider.loadFileFromSourceFilenameClosure = { _, _ in
+                try? await Task.sleep(for: .seconds(3600))
+                return .failure(.failedRetrievingFile)
+            }
+        } else if isDownloadError {
+            mediaProvider.loadFileFromSourceFilenameClosure = { _, _ in .failure(.failedRetrievingFile) }
+        }
+        
+        return TimelineMediaPreviewViewModel(initialItem: item,
+                                             timelineViewModel: TimelineViewModel.mock(timelineKind: timelineController.timelineKind,
+                                                                                       timelineController: timelineController),
+                                             mediaProvider: mediaProvider,
+                                             photoLibraryManager: PhotoLibraryManagerMock(.init()),
+                                             userIndicatorController: UserIndicatorControllerMock(),
+                                             appMediator: AppMediatorMock())
+    }
+}