UIKit Swift:阴影故障，上下文菜单

Question

我有一个带有阴影和上下文菜单的矩形。当我关闭这个上下文菜单时，矩形的阴影会延迟出现(~0.5秒)。完整矩形的阴影以及内部元素的阴影。我不知道我做错了什么

func collectionView(_ collectionView: UICollectionView, contextMenuConfigurationForItemAt indexPath: IndexPath, point: CGPoint) -> UIContextMenuConfiguration? {
    
    if collectionView == foodOnTheShelf {
        
        let config = UIContextMenuConfiguration(identifier: nil, previewProvider: nil) { _ in

            let edit = UIAction(title: "Изменить", image: UIImage(systemName: "pencil"), identifier: nil, discoverabilityTitle: nil, state: .off) { _ in
                self.alert.showAlert(viewController: self,
                                     image:  UIImage(named: test[indexPath.row].name)!,
                                     food: test[indexPath.row],
                                     picker: self.picker,
                                     consumePicker: self.consumePicker,
                                     unit: self.unit,
                                     currentWeigt: test[indexPath.row].weight,
                                     currentProductDate: test[indexPath.row].productionDate,
                                     currentExperationDate: test[indexPath.row].expirationDate,
                                     searchController: nil)
            }
            
            let delete = UIAction(title: "Удалить", image: UIImage(systemName: "trash"), attributes: .destructive) { _ in
                test.remove(at: indexPath.row)
                self.viewDidAppear(true)
            }
            return UIMenu(title: "", image: nil, identifier: nil, options: UIMenu.Options.displayInline , children: [edit, delete])
        }
        return config
    }
 return nil
    

}

Answer 1

基于这个答案，您可以向盘过渡视图添加阴影，这是在上下文菜单中断结束后显示的临时视图。

问题是这个转换视图是一个私有类(_UIContextMenuPlatterTransitionView)，所以如果使用它，应用程序将被拒绝。

func collectionView(_ collectionView: UICollectionView, willEndContextMenuInteraction configuration: UIContextMenuConfiguration, animator: UIContextMenuInteractionAnimating?) {
    guard let platter = platterTransitionView() else { return }
    addShadow(to: platter.layer) // add a shadow the same way you do for your cells
}

private func platterTransitionView() -> UIView? {
    guard let container = self.view.window?.subviews.filter({ type(of: $0) == NSClassFromString("_UIContextMenuContainerView") }).first else { return nil }
    return container.subviews.filter({ type(of: $0) == NSClassFromString("_UIContextMenuPlatterTransitionView") }).first
}

您也可以尝试在不检查其类的情况下访问转换视图，但这种方式并不安全/动态：

let platter = self.view.window?.subviews[2].subviews[1]