Ios打开和结束控制器的两种方式

方式1

打开
self.navigationController?.pushViewController(vc, animated: true)

退出
self.navigationController?.popViewController(animated: true)

方式二

打开
self.present(activityVC, animated: true, completion: { () -> Void in

    })

退出
self.dismiss(animated: false, completion: nil)