你可以用这个。把它放在AppDelegate.swift中。

func application(application: UIApplication, didFinishLaunchingWithOptions launchOptions: [NSObject: AnyObject]?) -> Bool {
        // Override point for customization after application launch.

        UINavigationBar.appearance().translucent = false
        UINavigationBar.appearance().barTintColor = UIColor(rgba: "#2c8eb5")
        UINavigationBar.appearance().tintColor = UIColor.whiteColor()
        UINavigationBar.appearance().titleTextAttributes = [NSForegroundColorAttributeName:UIColor.whiteColor()]

        return true
    }

如果你试了很多次都没有成功，你可以试试:

UIBarButtonItem.appearance(whenContainedInInstancesOf: [UINavigationBar.self]).tintColor = .red

其实，我试了很多次，才发现这种方法行得通。

在AppDelegate.swift中的didFinishLaunchingWithOptions函数中添加以下代码

var navigationBarAppearace = UINavigationBar.appearance()

navigationBarAppearace.tintColor = uicolorFromHex(0xffffff) // White color
navigationBarAppearace.barTintColor = uicolorFromHex(0x034517) // Green shade

// change navigation item title color
navigationBarAppearace.titleTextAttributes =[NSForegroundColorAttributeName:UIColor.whiteColor()]

你可以通过点击storyboard上的空白区域并在右边的工具栏中选择“Show the file inspector”来改变全局色调，你会在工具栏的底部看到“global tint”选项。

在Swift 4中，你可以使用以下方法来解决这个问题:

let navStyles = UINavigationBar.appearance()
// This will set the color of the text for the back buttons.
navStyles.tintColor = .white
// This will set the background color for navBar
navStyles.barTintColor = .black

斯威夫特5.3:

UINavigationBar.appearance().backIndicatorImage = UIImage(named: "custom-back-image")
UINavigationBar.appearance().backIndicatorTransitionMaskImage = UIImage(named: "custom-back-image")