它将通过-(void)viewDidLoad中的这一行来解决:

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

出于某种原因，它在编程上不适合我。但是，在故事板中设置它每次都有效。

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.redColor()

这段代码具有魔力。而不是红色，改变它作为你的愿望。

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()]

self.navigationController.navigationBar.tintColor = [UIColor whiteColor];

这适用于我，iOS 9.0+