Moving navigation bar in UINavigationController along with UIScrollView

gistfile1.m

- (void)scrollViewDidScroll:(UIScrollView *)scrollView
{
    CALayer *layer = self.navigationController.navigationBar.layer;
    CGFloat y = scrollView.contentOffset.y+scrollView.contentInset.top;
    if (y >= 0.0f) {
        layer.transform = CATransform3DMakeTranslation(0.0f, -y, 0.0f);
    } else {
        layer.transform = CATransform3DIdentity;
    }
}

if (a) {
print(a)
}