你应该加上这一行

 self.navigationController?.navigationBar.topItem?.backBarButtonItem?.tintColor = .black

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。

你应该这样使用:

navigationController?.navigationBar.barTintColor = .purple
navigationController?.navigationBar.tintColor = .white

如果你在Settings视图控制器中已经有了后退按钮，你想改变Payment Information视图控制器上后退按钮的颜色为其他颜色，你可以在Settings视图控制器的prepareforsegue中这样做:

override func prepare(for segue: UIStoryboardSegue, sender: Any?) { 
    if segue.identifier == "YourPaymentInformationSegue"
    {
        //Make the back button for "Payment Information" gray:
        self.navigationItem.backBarButtonItem?.tintColor = UIColor.gray               
    }
}

斯威夫特3

被点赞最多的答案是Swift 3不正确。

改变颜色的正确代码是:

self.navigationController?.navigationBar.tintColor = UIColor.white

如果你想改变颜色，改变UIColor。白色以上到所需的颜色