我必须这么做

UINavigationBar.appearance().tintColor = UIColor.whiteColor()
UINavigationBar.appearance().barStyle = .Black
UINavigationBar.appearance().backgroundColor = UIColor.blueColor()

否则背景颜色不会改变

iOs 14 +

init() {        
    let appearance = UINavigationBarAppearance()
    appearance.shadowColor = .clear // gets also rid of the bottom border of the navigation bar
    appearance.configureWithTransparentBackground() 
    UINavigationBar.appearance().standardAppearance = appearance
    UINavigationBar.appearance().scrollEdgeAppearance = appearance
}

iOS 10 Swift 3.0

如果你不介意使用swift框架，那么我们UINeraida将导航背景更改为UIColor或HexColor或UIImage，并以编程方式更改导航后退按钮文本，更改完整的前景文本颜色。

对于UINavigationBar

    neraida.navigation.background.color.hexColor("54ad00", isTranslucent: false, viewController: self)
    
    //Change navigation title, backbutton colour
    
    neraida.navigation.foreground.color.uiColor(UIColor.white, viewController: self)
    
    //Change navigation back button title programmatically
    
    neraida.navigation.foreground.backButtonTitle("Custom Title", ViewController: self)
    
    //Apply Background Image to the UINavigationBar
    
    neraida.navigation.background.image("background", edge: (0,0,0,0), barMetrics: .default, isTranslucent: false, viewController: self)

更新为Swift 3, 4, 4.2, 5+

// setup navBar.....
UINavigationBar.appearance().barTintColor = .black
UINavigationBar.appearance().tintColor = .white
UINavigationBar.appearance().titleTextAttributes = [NSForegroundColorAttributeName: UIColor.white]
UINavigationBar.appearance().isTranslucent = false

斯威夫特4

UINavigationBar.appearance().barTintColor = .black
UINavigationBar.appearance().tintColor = .white
UINavigationBar.appearance().titleTextAttributes = [NSAttributedStringKey.foregroundColor: UIColor.white]
UINavigationBar.appearance().isTranslucent = false

Swift 4.2, 5+

UINavigationBar.appearance().barTintColor = .black
UINavigationBar.appearance().tintColor = .white
UINavigationBar.appearance().titleTextAttributes = [NSAttributedString.Key.foregroundColor: UIColor.white]
UINavigationBar.appearance().isTranslucent = false

如果你想使用大标题，添加这一行:

UINavigationBar.navigationBar.prefersLargeTitles = true

也可以查看这里:https://github.com/hasnine/iOSUtilitiesSource

我写这篇文章是为了那些仍然对这里的解决方案有问题的人。

我使用的是Xcode版本11.4 (11E146)。为我工作的是:

navigationController?.navigationBar.barTintColor = UIColor.white
navigationController?.navigationBar.tintColor = UIColor.black

但是!如果你将storyboard中的barTintColor设置为“default”以外的任何值，这两行代码将不起作用。

小心，在Storyboard中设置回默认的barTintColor。 哦,苹果……

这里有一些非常基本的外观定制，你可以应用于整个应用程序:

UINavigationBar.appearance().backgroundColor = UIColor.greenColor()
UIBarButtonItem.appearance().tintColor = UIColor.magentaColor()
//Since iOS 7.0 UITextAttributeTextColor was replaced by NSForegroundColorAttributeName
UINavigationBar.appearance().titleTextAttributes = [UITextAttributeTextColor: UIColor.blueColor()]
UITabBar.appearance().backgroundColor = UIColor.yellowColor();

斯威夫特5.4.2:

UINavigationBar.appearance().backgroundColor = .green // backgorund color with gradient
// or
UINavigationBar.appearance().barTintColor = .green  // solid color
    
UIBarButtonItem.appearance().tintColor = .magenta
UINavigationBar.appearance().titleTextAttributes = [NSAttributedString.Key.foregroundColor : UIColor.blue]
UITabBar.appearance().barTintColor = .yellow

更多关于UIAppearance API在Swift你可以阅读这里。