ios swift 判断uiviewcontroller时push present 进来的 还是pop进来的
override func viewWillAppear(_ animated: Bool) { super.viewWillAppear(animated) //显示navbar self.navigationController?.setNavigationBarHidden(false, animated: true) if(isBeingPresented || isMovingToParent){ print("======push") }else{ print("======pop") } }