iOS 去掉navgationbar 底部线条

[[UINavigationBar appearance] setBarStyle:UIBarStyleBlackTranslucent];

[[UINavigationBar appearance] setBackgroundImage:[UIImage Color:kBackgroundColor Size:CGSizeMake(self.window.rootViewController.view.bounds.size.width, 60)] forBarMetrics:UIBarMetricsDefault];

    

    [[UINavigationBar appearance] setShadowImage:[[UIImage alloc] init]]; // 需要

 [UINavigationBar appearance].translucent = YES; //需要

// self.navigationController.navigationBar.translucent = NO;  // 不需要