self.navBar = [[UINavigationBar alloc] initWithFrame:CGRectMake(0, 0, self.view.frame.size.width, NAV_BAR_HEIGHT)]; [self.navBar setBackgroundImage:[UIImage imageWithColor:[UIColor clearColor]] forBarMetrics:UIBarMetricsDefault]; [self.navBar setBackgroundColor:UIColorFromRGBA(0xFF1E1E1E)]; self.navBar.shadowImage = [[UIImage alloc] init];

使用UIImage+Color2Image.h将透明色值转换为图片， 设置shadowImage去掉底部line