This iOS project show how to change the Navigation Bar style based on which ViewController is being shown.

Currently the only way I've seen working is through is using

UIApplication.shared.statusBarStyle = .lightContent // White content
UIApplication.shared.statusBarStyle = .default      // Black content

Usually I've seen the usage of UIApplicantion because the ViewController.preferredStatusBarStyle, when attached to a NavigationController, is completely ignored and the iOS uses the style defined by NavigationController.

I learned this by reading this article that explains shortly and also has codes to help.

This project now has two controllers. The FirstViewController has a button that calls the SecondViewController. Both define their titles and extends BaseViewController, that has a NavigationController implementation, and the solution of this "problem".

In the SecondViewController there is nothing implemented but the override of preferredStatusBarStyle.

SecondViewController.swift

override var preferredStatusBarStyle: UIStatusBarStyle {
    return .lightContent
}

By executing it's possible to see that when SecondViewController is called, the status bar becomes white (UIStatusBarStyle.lightContent) and whenever the FirstViewController is show, the status bar goes back to black (UIStatusBarStyle.default)

The solution found is very simple. Adding a extension to UINavigationController that overrides its preferredStatusBarStyle. That way is possible to make it returns the preferredStatusBarStyle from the ViewController on the top whenever is possible. If the ViewController do not overrides its preferredStatusBarStyle or if there is no ViewController on the top, the default value (UIStatusBarStyle.default) will be choosen.

In the case of this project, this extension was added in the BaseViewController class.

BaseViewController.swift

extension UINavigationController {
    open override var preferredStatusBarStyle: UIStatusBarStyle {
        return topViewController?.preferredStatusBarStyle ?? .default
    }
}