remove 1px line under uinavigationbar ios

@implementation UINavigationController(removeLine)

- (UIImageView *)findHairlineImageViewUnder:(UIView *)view
{
    if ([view isKindOfClass:UIImageView.class] && view.bounds.size.height <= 1.0)
    {
        return (UIImageView *)view;
    }
    
    for (UIView *subview in view.subviews)
    {
        UIImageView *imageView = [self findHairlineImageViewUnder:subview];
        
        if (imageView)
        {
            return imageView;
        }
    }
    
    return nil;
}

@end



// where you need to hide that line 
UIImageView *imgViewNav = [navController findHairlineImageViewUnder:navController.view];

// hide     
imgViewNav.hidden = YES;

// show
imgViewNav.hidden = NO;