导航栏背景颜色

Question

I am trying to change Navbar background color that will be push in navigation stack. I am using navigation controller under Tabbar controller. When I push view controller after changing the navbar color, in first attempt it does not work. when i reload this view by tapping tabbar item it works.

Why it is not working in first attempt?

view controller called from another Viewc controller

func showProjectDetails(indexPath: IndexPath) {
    let vc = storyboard?.instantiateViewController(withIdentifier: "MyTaskVC") as! MyTaskVC
    vc.viewMode = .ProjectDetails
    vc.currentProjectName = projects[indexPath.row].projectName
    navigationController?.pushViewController(vc, animated: true)
}

view conroller that pushed

override func viewWillAppear(_ animated: Bool) {
    super.viewWillAppear(animated)
let appearance = UINavigationBarAppearance()
        appearance.backgroundColor = .green
        appearance.titleTextAttributes = [.foregroundColor: UIColor.white]
        appearance.largeTitleTextAttributes = [.foregroundColor: UIColor.white]

        UINavigationBar.appearance().tintColor = .white
        UINavigationBar.appearance().standardAppearance = appearance
        UINavigationBar.appearance().compactAppearance = appearance
        UINavigationBar.appearance().scrollEdgeAppearance = appearance

}

Answer 1

Add this code in your viewDidLoad()

override func viewDidLoad() {
        super.viewDidLoad()

      if  let navigationBar = navigationController?.navigationBar {
        let appearance = UINavigationBarAppearance()
        appearance.backgroundColor = .green
        appearance.titleTextAttributes = [.foregroundColor: UIColor.red]
        appearance.largeTitleTextAttributes = [.foregroundColor: UIColor.white]

        let barAppearence = UIBarButtonItemAppearance()
        barAppearence.normal.titleTextAttributes = [.foregroundColor: UIColor.yellow]

        appearance.buttonAppearance = barAppearence

        navigationBar.scrollEdgeAppearance = appearance
        navigationBar.compactAppearance = appearance
        navigationBar.standardAppearance = appearance

        // Do any additional setup after loading the view.
    }
  }

Answer 2

You should create a subclass of UINavigationController and customize it, if you are using Interface Builder, you can set the NavigationController custom class in the Identify Inspector.

    import UIKit

    class YourNavigationController: UINavigationController { 

        override func viewWillAppear(_ animated: Bool) {
            super.viewWillAppear(animated)
            let barAppearance = UINavigationBar.appearance(whenContainedInInstancesOf: [YourNavigationController.self])
            barAppearance.tintColor = UIColor(named: "Blue" 
        } 

        override func viewDidLoad() {
            super.viewDidLoad()                        
        }    

      }

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