简单的解决方案- Swift 5

Create an extension: extension UIImage { class func hideNavBarLine(color: UIColor) -> UIImage? { let rect = CGRect(x: 0, y: 0, width: 1, height: 1) UIGraphicsBeginImageContext(rect.size) let context = UIGraphicsGetCurrentContext() context?.setFillColor(color.cgColor) context?.fill(rect) let navBarLine = UIGraphicsGetImageFromCurrentImageContext() UIGraphicsEndImageContext() return navBarLine } } Add this to viewDidLoad(): self.navigationController?.navigationBar.shadowImage = UIImage.hideNavBarLine(color: UIColor.clear)

-(void)viewWillAppear:(BOOL)animated {
    [super viewWillAppear:animated];

    UIImage *emptyImage = [UIImage new];
    self.navigationController.navigationBar.shadowImage = emptyImage;
    [self.navigationController.navigationBar setBackgroundImage:emptyImage forBarMetrics:UIBarMetricsDefault];
}

这可能听起来很愚蠢，但这个发际线只在viewController视图的背景色被设置为任何颜色时出现，除了白色。得知这个事实我很震惊。

如果你想让它毫不费力地消失只要设置控制器视图背景色为WHITE color。

在AppDelegate中，这已经全局地改变了导航栏的格式:

 func application(application: UIApplication, didFinishLaunchingWithOptions launchOptions: [NSObject: AnyObject]?) -> Bool {

    UINavigationBar.appearance().setBackgroundImage(UIImage(), forBarPosition: UIBarPosition.Any, barMetrics: UIBarMetrics.Default)
    UINavigationBar.appearance().shadowImage = UIImage()
    UINavigationBar.appearance().tintColor = UIColor.whiteColor()
    UINavigationBar.appearance().barTintColor = UIColor.redColor()
    UINavigationBar.appearance().translucent = false
    UINavigationBar.appearance().clipsToBounds = false
    UINavigationBar.appearance().backgroundColor = UIColor.redColor()
    UINavigationBar.appearance().titleTextAttributes = [NSFontAttributeName : (UIFont(name: "FONT NAME", size: 18))!, NSForegroundColorAttributeName: UIColor.whiteColor()] }

还没有在特定的VC上实现任何不同的东西，但这将帮助90%的人

斯威夫特4 //隐藏导航栏阴影线

navigationController?.navigationBar.shadowImage = UIImage()

我也遇到了同样的问题，但没有一个答案真正令人满意。以下是我对Swift3的看法:

func hideNavigationBarLine() {
    navigationController?.navigationBar.setBackgroundImage(UIImage(), for: .default)
    navigationController?.navigationBar.shadowImage = UIImage()
}

只需在viewDidLoad()中调用它。