导航栏被隐藏后pop的时候就会这样子，看着不开心☹️
解决：
- (void)viewWillAppear:(BOOL)animated{
[super viewWillAppear:animated];
[self.navigationController setNavigationBarHidden:YES animated:YES];
}
- (void)viewWillDisappear:(BOOL)animated{
[super viewWillDisappear:animated];
[self.navigationController setNavigationBarHidden:NO animated:YES];
}
接下来就如丝般顺滑😆
bug
