无法更改导航栏颜色

Question

I am trying to change the color of my navigation bar in a view which contains a UISearchController. I have previously set the color of my navigation bars for the whole app in my appDelegate, but i want this views nav bar to have a different color. The issue is that i dont know which function to place the code such that it will override the appDelegate code. For example, viewDidLoad and viewWilAppear do not change the color when the view first loads, only after i enter and cancel the searchController. Which function should i place the following?

UINavigationBar.appearance().backgroundColor = UIColor(red: 0, green: 0, blue: 0, alpha: 1)

Answer 1

There are two ways to do this. You can either modify the appearance proxy that you have set up in the AppDelegate for the whole app, or you can modify the individual navigationbar for the particular screen.

When you dismiss the view - you need to reset the barTintColor in the viewWillDisappear.

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

    // Set to new colour for whole app
    UINavigationBar.appearance().barTintColor = UIColor.blueColor()

    // Or, Set to new colour for just this navigation bar
    self.navigationController?.navigationBar.barTintColor = UIColor.blueColor()
}

override func viewWillDisappear(animated: Bool) {
    super.viewWillDisappear(animated)

    //Revert to old colour, whole app
    UINavigationBar.appearance().barTintColor = UIColor.redColor()

    //Revert to old colour, just this navigation bar
    self.navigationController?.navigationBar.barTintColor = UIColor.redColor()
}

Answer 2

您不应直接更改导航栏颜色，而应在viewWillAppear更改导航控制器的栏颜色，并在关闭视图时将其更改回来。