首先将navigationBar的isTranslucent属性设置为false以获得所需的颜色。然后像这样改变导航栏的颜色:

@IBOutlet var NavigationBar: UINavigationBar!

NavigationBar.isTranslucent = false
NavigationBar.barTintColor = UIColor (red: 117/255, green: 23/255, blue: 49/255, alpha: 1.0)

更新为Swift 3, 4, 4.2, 5+

// setup navBar.....
UINavigationBar.appearance().barTintColor = .black
UINavigationBar.appearance().tintColor = .white
UINavigationBar.appearance().titleTextAttributes = [NSForegroundColorAttributeName: UIColor.white]
UINavigationBar.appearance().isTranslucent = false

斯威夫特4

UINavigationBar.appearance().barTintColor = .black
UINavigationBar.appearance().tintColor = .white
UINavigationBar.appearance().titleTextAttributes = [NSAttributedStringKey.foregroundColor: UIColor.white]
UINavigationBar.appearance().isTranslucent = false

Swift 4.2, 5+

UINavigationBar.appearance().barTintColor = .black
UINavigationBar.appearance().tintColor = .white
UINavigationBar.appearance().titleTextAttributes = [NSAttributedString.Key.foregroundColor: UIColor.white]
UINavigationBar.appearance().isTranslucent = false

如果你想使用大标题，添加这一行:

UINavigationBar.navigationBar.prefersLargeTitles = true

也可以查看这里:https://github.com/hasnine/iOSUtilitiesSource

appearance()函数并不总是适用于我。所以我更喜欢创建一个NC对象并改变它的属性。

var navBarColor = navigationController!.navigationBar
navBarColor.barTintColor =
    UIColor(red:  255/255.0, green: 0/255.0, blue: 0/255.0, alpha: 100.0/100.0)
navBarColor.titleTextAttributes =
    [NSForegroundColorAttributeName: UIColor.whiteColor()]

此外，如果你想添加一个图像而不仅仅是文本，这也是可行的

var imageView = UIImageView(frame: CGRect(x: 0, y: 0, width: 70, height: 70))
imageView.contentMode = .ScaleAspectFit

var image = UIImage(named: "logo")
imageView.image = image
navigationItem.titleView = imageView

如果你使用iOS 13或14和大标题，并想改变导航栏的颜色，使用以下代码:

参考barTintColor不适用时导航栏是大标题

    fileprivate func setNavigtionBarItems() {
        if #available(iOS 13.0, *) {
            let appearance = UINavigationBarAppearance()
            appearance.configureWithDefaultBackground()
            appearance.backgroundColor = .brown
//            let naviFont = UIFont(name: "Chalkduster", size: 30) ?? .systemFont(ofSize: 30)
//            appearance.titleTextAttributes = [NSAttributedString.Key.font: naviFont]
            
            navigationController?.navigationBar.prefersLargeTitles = true
            navigationController?.navigationBar.standardAppearance = appearance
            navigationController?.navigationBar.scrollEdgeAppearance = appearance
            //navigationController?.navigationBar.compactAppearance = appearance
        } else {
            // Fallback on earlier versions
            navigationController?.navigationBar.barTintColor = .brown
        }
    }

这花了我1个小时来找出我的代码中的错误:(，因为我使用大标题，很难用largeTitle改变tintColor，为什么苹果让它这么复杂，这么多行只是做一个tintColor的navigationBar。

斯威夫特4:

在应用程序级别更改导航栏外观的完美代码。

// MARK: Navigation Bar Customisation

// To change background colour.
UINavigationBar.appearance().barTintColor = .init(red: 23.0/255, green: 197.0/255, blue: 157.0/255, alpha: 1.0)

// To change colour of tappable items.
UINavigationBar.appearance().tintColor = .white

// To apply textAttributes to title i.e. colour, font etc.
UINavigationBar.appearance().titleTextAttributes = [.foregroundColor : UIColor.white,
                                                    .font : UIFont.init(name: "AvenirNext-DemiBold", size: 22.0)!]
// To control navigation bar's translucency.
UINavigationBar.appearance().isTranslucent = false

编码快乐!

使用外观API和barTintColor颜色。

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