iOs 14 +

init() {        
    let appearance = UINavigationBarAppearance()
    appearance.shadowColor = .clear // gets also rid of the bottom border of the navigation bar
    appearance.configureWithTransparentBackground() 
    UINavigationBar.appearance().standardAppearance = appearance
    UINavigationBar.appearance().scrollEdgeAppearance = appearance
}

斯威夫特3

你可以在ViewDidLoad()中使用简单的一行代码

//Change Color
    self.navigationController?.navigationBar.barTintColor = UIColor.red
//Change Text Color
    self.navigationController?.navigationBar.titleTextAttributes = [NSForegroundColorAttributeName: UIColor.white]

Swift 5，一个简单的UINavigationController扩展方法。在这个答案的底部是扩展和预览。

第一个视图控制器(Home):

override func viewWillAppear(_ animated: Bool) {
    super.viewWillAppear(animated)

    navigationController?.setTintColor(.white)
    navigationController?.backgroundColor(.orange)
}

第二个视图控制器(详细信息):

override func viewWillAppear(_ animated: Bool) {
    super.viewWillAppear(animated)
    navigationController?.transparentNavigationBar()
    navigationController?.setTintColor(.black)
}

UINavigationController的扩展:

extension UINavigationController {
    func transparentNavigationBar() {
        self.navigationBar.setBackgroundImage(UIImage(), for: .default)
        self.navigationBar.shadowImage = UIImage()
        self.navigationBar.isTranslucent = true
    }

    func setTintColor(_ color: UIColor) {
        self.navigationBar.titleTextAttributes = [NSAttributedString.Key.foregroundColor: color]
        self.navigationBar.tintColor = color
    }

    func backgroundColor(_ color: UIColor) {
        navigationBar.setBackgroundImage(nil, for: .default)
        navigationBar.barTintColor = color
        navigationBar.shadowImage = UIImage()
    }
}

故事板视图:

预览:

在Swift 4中

您可以更改导航栏的颜色。只需在viewDidLoad()中使用下面的代码片段

导航栏颜色

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

导航栏文字颜色

self.navigationController?.navigationBar.titleTextAttributes = [NSAttributedStringKey.foregroundColor: UIColor.purple]

对于iOS 11大标题导航栏，你需要使用largeTitleTextAttributes属性

self.navigationController?.navigationBar.largeTitleTextAttributes = [NSAttributedStringKey.foregroundColor: UIColor.purple]

使用外观API和barTintColor颜色。

UINavigationBar.appearance().barTintColor = UIColor.greenColor()

Swift 4, iOS 12和Xcode 10更新

只需在viewDidLoad()中放入一行

navigationController?.navigationBar.barTintColor = UIColor.red