这里有一个不使用任何图像的方法，这是唯一适合我的方法:

self.navigationController.navigationBar.layer.shadowOpacity = 0;

不幸的是，您需要在每个不希望出现该行的文件上执行此操作。在appDelegate中没有办法这样做。

编辑:

设置shadowColor为nil是不需要的，这是你唯一需要的行。

        if #available(iOS 13.0, *) {
            let appearance = UINavigationBarAppearance()
            appearance.backgroundColor          = Colors.color_app
            appearance.titleTextAttributes      = [.foregroundColor : UIColor.white]
            appearance.largeTitleTextAttributes = [.foregroundColor : UIColor.white]
            appearance.shadowColor = .clear
            appearance.shadowImage = UIImage()
            
            UINavigationBar.appearance().tintColor            = .white
            UINavigationBar.appearance().standardAppearance   = appearance
            UINavigationBar.appearance().compactAppearance    = appearance
            UINavigationBar.appearance().scrollEdgeAppearance = appearance
        } else {
            UINavigationBar.appearance().barTintColor        = Colors.color_app
            UINavigationBar.appearance().tintColor           = .white
            UINavigationBar.appearance().titleTextAttributes = [NSAttributedString.Key.foregroundColor : UIColor.white]
            if #available(iOS 11.0, *) {
                UINavigationBar.appearance().largeTitleTextAttributes = [NSAttributedString.Key.foregroundColor: UIColor.white]
            }
            UINavigationBar.appearance().isTranslucent = false
            
            UINavigationBar.appearance().shadowImage = UIImage()
            UINavigationBar.appearance().setBackgroundImage(UIImage(), for: .default)
        }

试试这个:

[[UINavigationBar appearance] setBackgroundImage: [UIImage new]  
                                   forBarMetrics: UIBarMetricsDefault];

[UINavigationBar appearance].shadowImage = [UIImage new];

下图有解释(iOS7导航栏):

检查这个SO问题: iOS7 -改变UINavigationBar的边框颜色

酒吧风格的黑色适合我。

[[UINavigationBar appearance] setBarStyle:UIBarStyleBlack];

我拥有的所有属性(以防万一):

    [[UINavigationBar appearance] setBarTintColor:color];
    [[UINavigationBar appearance] setTranslucent:NO];
    [[UINavigationBar appearance] setShadowImage:[UIImage new]];
    [[UINavigationBar appearance] setBarStyle:UIBarStyleBlack];

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)

对我来说，最简单的方法是创建一个具有所需颜色的png(它只需要一个像素乘以一个像素的尺寸)，然后设置backgroundImage和shadowImage:

let greenPixel = UIImage(named: "TheNameOfYourPng")
navigationBar.setBackgroundImage(greenPixel, forBarMetrics: UIBarMetrics.Default)
navigationBar.shadowImage = greenPixel