我必须这么做

UINavigationBar.appearance().tintColor = UIColor.whiteColor()
UINavigationBar.appearance().barStyle = .Black
UINavigationBar.appearance().backgroundColor = UIColor.blueColor()

否则背景颜色不会改变

如果你有定制的导航控制器，你可以使用上面的代码片段。 在我的例子中，我使用了如下的代码段。

Swift 3.0, XCode 8.1版本

navigationController.navigationBar.barTintColor = UIColor.green

导航栏文本:

navigationController.navigationBar.titleTextAttributes = [NSForegroundColorAttributeName: UIColor.orange]

这是非常有益的谈话。

导航栏:

navigationController?.navigationBar.barTintColor = UIColor.green

用你想要的任何UIColor替换greenColor，如果你喜欢，你也可以使用RGB。

导航栏文本:

navigationController?.navigationBar.titleTextAttributes = [.foregroundColor: UIColor.orange]

用你喜欢的颜色替换orangeColor。

标签栏:

tabBarController?.tabBar.barTintColor = UIColor.brown

标签栏文本:

tabBarController?.tabBar.tintColor = UIColor.yellow

最后两个，用你选择的颜色替换brownColor和yellowColor。

在AppDelegate中试试这个:

//MARK:- ~~~~~~~~~~setupApplicationUIAppearance Method
func setupApplicationUIAppearance() {

    UIApplication.shared.statusBarView?.backgroundColor = UIColor.clear

    var preferredStatusBarStyle: UIStatusBarStyle {
        return .lightContent
    }

    UINavigationBar.appearance().tintColor = #colorLiteral(red: 1, green: 1, blue: 1, alpha: 1)
    UINavigationBar.appearance().barTintColor =  UIColor.white
    UINavigationBar.appearance().isTranslucent = false

    let attributes: [NSAttributedString.Key: AnyObject]

    if DeviceType.IS_IPAD{
        attributes = [
            NSAttributedString.Key.foregroundColor: UIColor.white,
            NSAttributedString.Key.font: UIFont(name: "HelveticaNeue", size: 30)
            ] as [NSAttributedString.Key : AnyObject]
    }else{
        attributes = [
            NSAttributedString.Key.foregroundColor: UIColor.white
        ]
    }
    UINavigationBar.appearance().titleTextAttributes = attributes
}

iOS 13

func setupNavigationBar() {
    //        if #available(iOS 13, *) {
    //            let window = UIApplication.shared.windows.filter {$0.isKeyWindow}.first
    //            let statusBar = UIView(frame: window?.windowScene?.statusBarManager?.statusBarFrame ?? CGRect.zero)
    //            statusBar.backgroundColor = #colorLiteral(red: 0.2784313725, green: 0.4549019608, blue: 0.5921568627, alpha: 1) //UIColor.init(hexString: "#002856")
    //            //statusBar.tintColor = UIColor.init(hexString: "#002856")
    //            window?.addSubview(statusBar)
    //            UINavigationBar.appearance().tintColor = #colorLiteral(red: 1, green: 1, blue: 1, alpha: 1)
    //            UINavigationBar.appearance().barTintColor = #colorLiteral(red: 1, green: 1, blue: 1, alpha: 1)
    //            UINavigationBar.appearance().isTranslucent = false
    //            UINavigationBar.appearance().backgroundColor = #colorLiteral(red: 0.2784313725, green: 0.4549019608, blue: 0.5921568627, alpha: 1)
    //            UINavigationBar.appearance().titleTextAttributes = [NSAttributedString.Key.foregroundColor : UIColor.white]
    //        }
    //        else
    //        {
    UIApplication.shared.statusBarView?.backgroundColor = #colorLiteral(red: 0.2784313725, green: 0.4549019608, blue: 0.5921568627, alpha: 1)
    UINavigationBar.appearance().tintColor = #colorLiteral(red: 1, green: 1, blue: 1, alpha: 1)
    UINavigationBar.appearance().barTintColor = #colorLiteral(red: 1, green: 1, blue: 1, alpha: 1)
    UINavigationBar.appearance().isTranslucent = false
    UINavigationBar.appearance().backgroundColor = #colorLiteral(red: 0.2784313725, green: 0.4549019608, blue: 0.5921568627, alpha: 1)
    UINavigationBar.appearance().titleTextAttributes = [NSAttributedString.Key.foregroundColor : UIColor.white]
    //        }
}

扩展

extension UIApplication {

var statusBarView: UIView? {
    if responds(to: Selector(("statusBar"))) {
        return value(forKey: "statusBar") as? UIView
    }
    return nil
}}

Swift 4, iOS 12和Xcode 10更新

只需在viewDidLoad()中放入一行

navigationController?.navigationBar.barTintColor = UIColor.red

这里有一些非常基本的外观定制，你可以应用于整个应用程序:

UINavigationBar.appearance().backgroundColor = UIColor.greenColor()
UIBarButtonItem.appearance().tintColor = UIColor.magentaColor()
//Since iOS 7.0 UITextAttributeTextColor was replaced by NSForegroundColorAttributeName
UINavigationBar.appearance().titleTextAttributes = [UITextAttributeTextColor: UIColor.blueColor()]
UITabBar.appearance().backgroundColor = UIColor.yellowColor();

斯威夫特5.4.2:

UINavigationBar.appearance().backgroundColor = .green // backgorund color with gradient
// or
UINavigationBar.appearance().barTintColor = .green  // solid color
    
UIBarButtonItem.appearance().tintColor = .magenta
UINavigationBar.appearance().titleTextAttributes = [NSAttributedString.Key.foregroundColor : UIColor.blue]
UITabBar.appearance().barTintColor = .yellow

更多关于UIAppearance API在Swift你可以阅读这里。