UIAlertController使应用程序无响应

Question

这是我用于在actionSheet样式中显示和处理UIAlertController的代码。

actionSheetController = UIAlertController(title: nil, message: nil, preferredStyle: .actionSheet)
        actionSheetController.view.tintColor = TGProjectHandler.getAppThemeColor()
        let cancelAction: UIAlertAction = UIAlertAction(title: "Cancel", style: .cancel) { action -> Void in
            //Just dismiss the action sheet
        }
        actionSheetController.addAction(cancelAction)

        let inviteMemberAction: UIAlertAction = UIAlertAction(title: "Invite member", style: .default) { action -> Void in
            let newActivityInviteTableController = NewActivityInviteTableViewController()
            newActivityInviteTableController.invite_type = 1
            newActivityInviteTableController.activity = self.activity
            self.invitation_type = 1
            let navController = UINavigationController(rootViewController: newActivityInviteTableController)
            navController.navigationBar.barTintColor = self.navigationController?.navigationBar.barTintColor
            navController.navigationBar.tintColor = self.navigationController?.navigationBar.tintColor
            self.navigationController?.navigationBar.titleTextAttributes = [NSForegroundColorAttributeName: UIColor.white]
            navController.navigationBar.isTranslucent = false
            newActivityInviteTableController.navigationItem.leftBarButtonItem = UIBarButtonItem(barButtonSystemItem: .cancel, target: self, action: #selector(self.dismissPopover))
            newActivityInviteTableController.navigationItem.rightBarButtonItem = UIBarButtonItem(title: "Add", style: .plain, target: newActivityInviteTableController.self, action: #selector(newActivityInviteTableController.sendInviteRequest))
            if (!(newActivityInviteTableController == nil))
            {
                self.navigationController!.present(navController, animated: true, completion: nil)
            }
        }
        actionSheetController.addAction(inviteMemberAction)
        let inviteChildAction: UIAlertAction = UIAlertAction(title: "Invite child", style: .default)
        { action -> Void in

            let newActivityInviteChildTableController = NewActivityInviteChildTableViewController()
            self.invitation_type = 2
            newActivityInviteChildTableController.activity = self.activity
            let navController = UINavigationController(rootViewController: newActivityInviteChildTableController)
            navController.navigationBar.barTintColor = self.navigationController?.navigationBar.barTintColor
            navController.navigationBar.isTranslucent = false
            navController.navigationBar.tintColor = UIColor.white
            self.navigationController?.navigationBar.titleTextAttributes = [NSForegroundColorAttributeName: UIColor.white]
            newActivityInviteChildTableController.navigationItem.leftBarButtonItem = UIBarButtonItem(barButtonSystemItem: .cancel, target: self, action: #selector(self.dismissPopover))

            newActivityInviteChildTableController.navigationItem.rightBarButtonItem = UIBarButtonItem(title: "Add", style: .plain, target: newActivityInviteChildTableController.self, action: #selector(newActivityInviteChildTableController.sendInviteRequest))
            if (!(newActivityInviteChildTableController == nil))
            {
                self.navigationController!.present(navController, animated: true, completion: nil)
            }

        }

        actionSheetController.addAction(inviteChildAction)
        self.present(actionSheetController, animated: true, completion: nil)

虽然是随机的，但有时它会让应用程序无响应。如果我多次显示/关闭 actionSheetController ，则 actionSheetController 会保留在屏幕上，然后应用就会无响应触摸。