问在iPad中长滑动Tableview单元格崩溃

EN

DispatchQueue.main.async {
            self.addAlertForiPad(alert: alertController)
            self.present(alertController, animated: true, completion: nil)
        }

    public func addAlertForiPad(alert: UIAlertController) {
        DispatchQueue.main.async {
            if let popoverPresentationController = alert.popoverPresentationController {
                popoverPresentationController.sourceView = self.view
                popoverPresentationController.sourceRect = CGRect(x: self.view.bounds.midX, y: self.view.bounds.midY, width: 0, height: 0)
                popoverPresentationController.permittedArrowDirections = []
            }
        }
    }