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
    }

    self.navigationController?.navigationBar.tintColor = UIColor.black // to change the all text color in navigation bar or navigation 
    self.navigationController?.navigationBar.barTintColor = UIColor.white // change the navigation background color
    self.navigationController?.navigationBar.titleTextAttributes = [NSForegroundColorAttributeName:UIColor.black] // To change only navigation bar title text color

在AppDelegate类中使用此代码，在didFinishLaunchingWithOptions中。

func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplicationLaunchOptionsKey: Any]?) -> Bool {

UINavigationBar.appearance().tintColor = .white

}

它将通过-(void)viewDidLoad中的这一行来解决:

self.navigationItem.backBarButtonItem.tintColor = UIColor.whiteColor;

对于Swift 2.0，要更改导航栏的色调颜色，标题文本和后退按钮的色调颜色更改，请使用AppDelegate.swift中的以下命令

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

  // Override point for customization after application launch.


    //Navigation bar tint color change

    UINavigationBar.appearance().barTintColor = UIColor(red: 42/255.0, green: 140/255.0, blue: 166/255.0, alpha: 0.5)

    //Back button tint color change

    UINavigationBar.appearance().barStyle = UIBarStyle.Default
    UINavigationBar.appearance().tintColor =  UIColor(red: 204/255.0, green: 255/255.0, blue: 204/255.0, alpha: 1)

    //Navigation Menu font tint color change

    UINavigationBar.appearance().titleTextAttributes = [NSForegroundColorAttributeName: UIColor(red: 204/255.0, green: 255/255.0, blue: 204/255.0, alpha: 1), NSFontAttributeName: UIFont(name: "OpenSans-Bold", size: 25)!]//UIColor(red: 42/255.0, green: 140/255.0, blue: 166/255.0, alpha: 1.0)

    UIApplication.sharedApplication().statusBarStyle = UIStatusBarStyle.LightContent


    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。