swift hide navigation bar

1override func viewWillAppear(_ animated: Bool) {
2    super.viewWillAppear(animated)
3    navigationController?.setNavigationBarHidden(true, animated: animated)
4}
5
6override func viewWillDisappear(_ animated: Bool) {
7    super.viewWillDisappear(animated)
8    navigationController?.setNavigationBarHidden(false, animated: animated)
9}