hidingtopbar.m

// I had to set the navigation bar to hidden, then add the top and bottom controls as a view. 
// I don't think you can control the navigation bar directly. 
- (void)viewDidLoad {
    [self.navigationController setNavigationBarHidden:YES animated:NO]; 
}

- (void)showControls {
    [UIView animateWithDuration:0.2 animations:^{
        CGRect bottomFrame = self.bottomControlsView.frame;
        bottomFrame.origin.y = self.view.frame.size.height - bottomFrame.size.height;
        self.bottomControlsView.frame = bottomFrame;
        
        CGRect topFrame = self.topControlsView.frame;
        topFrame.origin.y = 0;
        self.topControlsView.frame = topFrame;
    }];
}

- (void)hideControls {
    [UIView animateWithDuration:0.2 animations:^{
        CGRect bottomFrame = self.bottomControlsView.frame;
        bottomFrame.origin.y = self.view.frame.size.height;
        self.bottomControlsView.frame = bottomFrame;
        
        CGRect topFrame = self.topControlsView.frame;
        topFrame.origin.y = -topFrame.size.height;
        self.topControlsView.frame = topFrame;
    }];
}