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

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()]

在故事板中很容易设置:

我更喜欢自定义NavigationController而不是设置全局ui，或者放在ViewController中。

这是我的解决方案

class AppNavigationController : UINavigationController {

  override func viewDidLoad() {
    super.viewDidLoad()
    self.delegate = self
  }

  override func viewWillAppear(_ animated: Bool) {

  }

}
extension AppNavigationController : UINavigationControllerDelegate {

  func navigationController(_ navigationController: UINavigationController, willShow viewController: UIViewController, animated: Bool) {
    let backButtonItem = UIBarButtonItem(
      title: "   ",
      style: UIBarButtonItem.Style.plain,
      target: nil,
      action: nil)
    backButtonItem.tintColor = UIColor.gray
    viewController.navigationItem.backBarButtonItem = backButtonItem
  }

  func navigationController(_ navigationController: UINavigationController, didShow viewController: UIViewController, animated: Bool) {

  }

}

此外，如果你使用全局设置ui，如UIBarButtonItem.appearance()，你不需要像EKEventEditViewController,PickerViewController等苹果Api。tintColor = .white