我一直在努力找出如何解决这个问题。在这一行popover.permittedArrowDirections=(.Up|.Down)上面写着“Typeofexpressionisambiquouswithoutmorecontext.”这是代码示例:ifletpopover=alert.popoverPresentationController{popover.sourceView=imageViewpopover.sourceRect=imageView.boundspopover.permittedArrowDirections=(.Up|.Down)}