导航栏出现黑色？

Question

我正在为我的应用程序启动时设置新的导航。但是当我启动它时，它显示为黑色 animation.After 黑色，它设置了导航栏。请告诉我问题是什么。

我正在使用下面的代码

var controller = UIViewController()

//App Theming
var navController = UINavigationController()
navController.navigationBar.barTintColor = UIColor.white
navController.navigationBar.tintColor = UIColor.white
navController.navigationBar.titleTextAttributes = [NSAttributedStringKey.foregroundColor: UIColor.white]
navController.navigationBar.shadowImage = UIImage()

navController.navigationBar.setBackgroundImage(UIImage(), for: .default)
navController.navigationBar.isTranslucent = false
navController = UINavigationController(rootViewController: viewcontroller)
navController.navigationBar.isHidden = true

let appDelegate = UIApplication.shared.delegate as! AppDelegate
appDelegate.window?.rootViewController = navController
appDelegate.window?.makeKeyAndVisible()

Answer 1

问题出在这一行：

navController.navigationBar.isHidden = true

删除后重试。

Answer 2

请使用下面的代码段

In this I am using ViewController from Main storyboard

   // mainStoryboard
        let mainStoryboard = UIStoryboard(name: "Main", bundle: nil)

        // rootViewController
        let rootViewController = mainStoryboard.instantiateViewController(withIdentifier: "ViewController") as? ViewController

        // navigationController
        let navigationController = UINavigationController(rootViewController: rootViewController!)

        //App Theming
        navigationController.navigationBar.barTintColor = UIColor.white
        navigationController.navigationBar.tintColor = UIColor.white
        navigationController.navigationBar.titleTextAttributes = [NSAttributedStringKey.foregroundColor: UIColor.white]
        navigationController.title = "Testing Th"
        navigationController.navigationBar.shadowImage = UIImage()


        navigationController.navigationBar.setBackgroundImage(UIImage(), for: .default)
        navigationController.navigationBar.isTranslucent = false
        navigationController.navigationBar.isHidden = true
        // self.window
        self.window = UIWindow(frame: UIScreen.main.bounds)
        self.window!.rootViewController = navigationController
        self.window!.makeKeyAndVisible()

如果我取消隐藏导航栏

    navigationController.navigationBar.isHidden = false

你可以清楚地看到结果

Answer 3

我看到你没有给 navigationController 任何 viewControllers。
您需要至少向导航控制器传递一个 viewController 以便它知道哪个 viewController 开始您的导航过程来自，遵循以下代码：

var window: 用户界面窗口？让 nav = UINavigationController()

1- 这是我声明初始 viewController 的地方（我希望我的导航过程从这里开始）

var  main = HomeViewController(nibName: "HomeViewController", bundle: nil)

2- 这是我给 navigationController 第一个 viewController 开始的地方。

    window?.rootViewController = nav
    nav.viewControllers = [main]//you need to have this line
    nav.isNavigationBarHidden = true
    window?.makeKeyAndVisible()

Answer 4

好的，我刚注意到你在使用故事板，试试这个：

var storyboard = UIStoryboard(name: "Main", bundle: nil)
var ivc = storyboard.instantiateViewController(withIdentifier: "ViewController") as? ViewController
navigationController?.pushViewController(anIvc, animated: true)
window.rootViewController = ivc
window.rootViewController = navigationController
window.makeKeyAndVisible()

Answer 5

您的代码应放在

import UIKit

// AppDelegate class file

func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplicationLaunchOptionsKey: Any]?) -> Bool {

    // Be attentive. controller allocated withou any layout. Change to custom controller class or load from IB resource (storyboard/nib)
    let controller = UIViewController()
    let navigationController = rootNavigationController
    // Setup viewControllers. Just one controller as root
    navigationController.viewControllers = [controller]
    // You already have a reference to window in your AppDelegate
    window.rootViewController = navigationController
    window.makeKeyAndVisible()
}

extension AppDelegate {

    // Move out of AppDelegate class code to create theming NavigationController
    private var rootNavigationController: UINavigationController {
        let navController = UINavigationController()
        navController.navigationBar.barTintColor = UIColor.white
        navController.navigationBar.tintColor = UIColor.white
        navController.navigationBar.titleTextAttributes = [NSAttributedStringKey.foregroundColor: UIColor.white]
        navController.navigationBar.shadowImage = UIImage()
        navController.navigationBar.setBackgroundImage(UIImage(), for: .default)
        navController.navigationBar.isTranslucent = false
        navController.navigationBar.isHidden = true
        // If it theme for all application you should use appearances
        /* For Example
        UINavigationBar.appearance().titleTextAttributes = [NSAttributedStringKey.foregroundColor: UIColor.white]
        UINavigationBar.appearance().tintColor = .white
        */

        return navController
    }

}

您可能的错误：

控制器实例没有任何布局。默认 ViewController 什么都没有
您从不同的地方编码调用。它是您调用 AppDelegate 实例的市场。配置你的 rootViewController 在 didFinishLoading
您有一个单独的 ViewController 作为 root

导航栏出现黑色？

Navigation bar appear from black color?

uinavigationbar

ios

swift