顶部酒吧3D触摸窥视

Question

我有一个 UICollectionView ，在 3D Touch 'ed时显示'Peek'。作为默认行为，'Peek'忽略导航栏。

但是，我确实想要显示一个栏，就像下面显示的 iMessage Peek 一样：

Collection View Controller＆amp; Peek View Controller位于导航视图控制器内部。

我在下面的Apple示例代码中有以下代码片段，我正在尝试修改以满足上述需求：

extension ChatTableViewController: UIViewControllerPreviewingDelegate {
    func previewingContext(_ previewingContext: UIViewControllerPreviewing, viewControllerForLocation location: CGPoint) -> UIViewController? {
        guard let indexPath = tableView.indexPathForRow(at: location) else { return nil }

        let storyboard = UIStoryboard(name: "Main", bundle: nil)
        let viewController = storyboard.instantiateViewController(withIdentifier: ChatDetailViewController.identifier)
        guard let chatDetailViewController = viewController as? ChatDetailViewController else { return nil }

        chatDetailViewController.chatItem = chatItem(at: indexPath)
        let cellRect = tableView.rectForRow(at: indexPath)
        previewingContext.sourceRect = previewingContext.sourceView.convert(cellRect, from: tableView)
        chatDetailViewController.isReplyButtonHidden = true

        return chatDetailViewController
    }

    func previewingContext(_ previewingContext: UIViewControllerPreviewing, commit viewControllerToCommit: UIViewController) {
        if let chatDetailViewController = viewControllerToCommit as? ChatDetailViewController {
            chatDetailViewController.isReplyButtonHidden = false
        }
        show(viewControllerToCommit, sender: self)
    }

更新

感谢 Leo Natan ，我能够完成上述任务：

extension ChatTableViewController: UIViewControllerPreviewingDelegate {
    func previewingContext(_ previewingContext: UIViewControllerPreviewing, viewControllerForLocation location: CGPoint) -> UIViewController? {
        guard let indexPath = tableView.indexPathForRow(at: location) else { return nil }

        let storyboard = UIStoryboard(name: "Main", bundle: nil)
        let viewController = storyboard.instantiateViewController(withIdentifier: ChatDetailViewController.identifier)
        guard let chatDetailViewController = viewController as? ChatDetailViewController else { return nil }

        chatDetailViewController.chatItem = chatItem(at: indexPath)
        let cellRect = tableView.rectForRow(at: indexPath)
        previewingContext.sourceRect = previewingContext.sourceView.convert(cellRect, from: tableView)
        chatDetailViewController.isReplyButtonHidden = true

        let navigationController = UINavigationController(rootViewController: viewController
        return navigationController
    }

    func previewingContext(_ previewingContext: UIViewControllerPreviewing, commit viewControllerToCommit: UIViewController) {
        if let chatDetailViewController = viewControllerToCommit as? ChatDetailViewController {
            chatDetailViewController.isReplyButtonHidden = false
        }
        show(viewControllerToCommit, sender: self)
    }

然而，这会创建一个新的导航控制器。如果我想要使用相同的导航控制器，我可以这样做：

func previewingContext(_ previewingContext: UIViewControllerPreviewing, commit viewControllerToCommit: UIViewController) {
    if let chatDetailViewController = viewControllerToCommit as? ChatDetailViewController {
        chatDetailViewController.isReplyButtonHidden = false
    }

    show((viewControllerToCommit as UIController).viewControllers[0], sender: self)
}

show（（viewControllerToCommit as UIController）.viewControllers [0]，sender：self）从它的导航控制器中提取viewController。这有什么缺点吗？

Answer 1

在previewingContext(_:, viewControllerForLocation:)中，将视图控制器包装在UINavigationController中并返回。