ios去除导航栏下方的横线

  //去除导航栏下方的横线

    [navigationBar setBackgroundImage:[UIImage imageWithColor:[self colorFromHexRGB:@"33cccc"]]

                       forBarPosition:UIBarPositionAny

                           barMetrics:UIBarMetricsDefault];

    [navigationBar setShadowImage:[UIImage new]];