Add a preview provider to the context menu.

Riot/Modules/Home/HomeViewController.m

@@ -673,12 +673,14 @@
 
 - (UIContextMenuConfiguration *)collectionView:(UICollectionView *)collectionView contextMenuConfigurationForItemAtIndexPath:(NSIndexPath *)indexPath point:(CGPoint)point API_AVAILABLE(ios(13.0))
 {
+    id<MXKRecentCellDataStoring> cellData = [recentsDataSource cellDataAtIndexPath:[NSIndexPath indexPathForRow:indexPath.item inSection:collectionView.tag]];
     MXRoom *room = [self.dataSource getRoomAtIndexPath:[NSIndexPath indexPathForRow:indexPath.row inSection:collectionView.tag]];
     NSString *roomId = room.roomId;
     
-    return [UIContextMenuConfiguration configurationWithIdentifier:roomId
-                                                   previewProvider:nil
-                                                    actionProvider:^UIMenu * _Nullable(NSArray<UIMenuElement *> * _Nonnull suggestedActions) {
+    return [UIContextMenuConfiguration configurationWithIdentifier:roomId previewProvider:^UIViewController * _Nullable {
+        // Add a preview using the cell's data to prevent the avatar and displayname from changing with a room list update.
+        return [[RoomPreviewViewController alloc] initWithCellData:cellData];
+    } actionProvider:^UIMenu * _Nullable(NSArray<UIMenuElement *> * _Nonnull suggestedActions) {
         MXWeakify(self);
         
         BOOL isDirect = room.isDirect;

Riot/Modules/Home/RoomContextPreviewViewController.swift

@@ -0,0 +1,55 @@
+// 
+// Copyright 2021 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
+
+/// A view controller that provides a preview of a room for use in context menus.
+@objcMembers
+class RoomPreviewViewController: UIViewController {
+    
+    // MARK: - Constants
+    private enum Constants {
+        static let size = CGSize(width: 80, height: 115)
+    }
+    
+    // MARK: - Private
+    
+    private var cellData: MXKCellData
+    
+    // MARK: - Setup
+    
+    init(cellData: MXKCellData) {
+        self.cellData = cellData
+        super.init(nibName: nil, bundle: nil)
+    }
+    
+    required init?(coder: NSCoder) {
+        fatalError("init(coder:) has not been implemented")
+    }
+    
+    // MARK: - Lifecyle
+    
+    override func viewDidLoad() {
+        super.viewDidLoad()
+        
+        let cell = RoomCollectionViewCell(frame: CGRect(origin: .zero, size: Constants.size))
+        cell.render(cellData)
+        view.vc_addSubViewMatchingParent(cell)
+        
+        preferredContentSize = Constants.size
+    }
+    
+}

Riot/SupportingFiles/Riot-Bridging-Header.h

@@ -50,6 +50,7 @@
 #import "PlainRoomTimelineCellProvider.h"
 #import "BubbleRoomTimelineCellProvider.h"
 #import "RoomSelectedStickerBubbleCell.h"
+#import "RoomCollectionViewCell.h"
 
 // MatrixKit common imports, shared with all targets
 #import "MatrixKit-Bridging-Header.h"

changelog.d/4883.bugfix

@@ -1 +1 @@
-Fix bugs when building with Xcode 13: bar appearance / header padding / space avatar content size
+Fix bugs when building with Xcode 13: bar appearance / header padding / space avatar content size. Additionally, use UIKit context menus on the home screen.