IOS 黑暗模式简单理解

class ViewController: UIViewController {
    override func viewDidLoad() {
        super.viewDidLoad()
        // Do any additional setup after loading the view.
    }
    @IBAction func changeThemeHanlder(_ sender: Any) {
        if overrideUserInterfaceStyle == .dark {
            overrideUserInterfaceStyle = .light
        }
        else{
            overrideUserInterfaceStyle = .dark
        }
    }
}

UIView.transition(with: view, duration: 0.5, options: .transitionCrossDissolve, animations: {
            if self.overrideUserInterfaceStyle == .dark {
                self.overrideUserInterfaceStyle = .light
            }
            else{
                self.overrideUserInterfaceStyle = .dark
            }
        }, completion: nil)