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
}

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

确保将按钮状态设置为.normal

extension UINavigationBar {

    func makeContent(color: UIColor) {
        let attributes: [NSAttributedString.Key: Any]? = [.foregroundColor: color]

        self.titleTextAttributes = attributes
        self.topItem?.leftBarButtonItem?.setTitleTextAttributes(attributes, for: .normal)
        self.topItem?.rightBarButtonItem?.setTitleTextAttributes(attributes, for: .normal)
    }
}

ps iOS 12, Xcode 10.1

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
}}

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。

iOS 8 (swift)

let font: UIFont = UIFont(name: "fontName", size: 17)   
let color = UIColor.backColor()
self.navigationController?.navigationBar.topItem?.backBarButtonItem?.setTitleTextAttributes([NSFontAttributeName: font,NSForegroundColorAttributeName: color], forState: .Normal)