iOS-通过preferredStatusBarStyle控制电池栏颜色

1

在info.plist文件添加"View controller-based status bar appearance", 值YES

2.code

// MARK: - 导航控制器
class Nav:UINavigationController {
    override init(rootViewController: UIViewController) {
        super.init(rootViewController: rootViewController)
    }
    
    override init(nibName nibNameOrNil: String?, bundle nibBundleOrNil: Bundle?) {
        super.init(nibName: nibNameOrNil, bundle: nibBundleOrNil)
    }
    
    required public init?(coder aDecoder: NSCoder) {
        super.init(coder: aDecoder)
    }
 
    override var childForStatusBarStyle: UIViewController?{
        //由子页面去控制电池栏颜色
        return self.topViewController
    }
}

// MARK: - 导航控制器的rootViewController
class ViewController: UIViewController {

    override func viewDidLoad() {
        super.viewDidLoad()
        // Do any additional setup after loading the view.
        let btn = UIButton.init(frame: CGRect.init(x: 100, y: 100, width: 100, height: 50))
        btn.setTitle("push vc", for: .normal)
        btn.backgroundColor = .blue
        btn.addTarget(self, action: #selector(onBtn), for: .touchUpInside)
        self.view.addSubview(btn)
    }

    @objc func onBtn(){
        self.navigationController?.pushViewController(VC(), animated: true)
    }
    
    override var preferredStatusBarStyle: UIStatusBarStyle {
        //(电池栏黑色)
        return .default
    }

}

// MARK: - 导航控制器的子VC
class VC: UIViewController {

    override func viewDidLoad() {
        super.viewDidLoad()
        // Do any additional setup after loading the view.
        self.view.backgroundColor = .blue
        
        //主动触发preferredStatusBarStyle
        self.setNeedsStatusBarAppearanceUpdate()
    }

    override var preferredStatusBarStyle: UIStatusBarStyle {
        //(电池栏白色)
        return .lightContent
    }
}

3.注意
场景：UIViewController 的层级比较复杂，简述如下：
A–> B -> C
其中A是带UINavigationController的一个控制器；B是present出来的一个控制器，坑爹的来了，C又是B push出来的带UINavigationController的一个控制器；而且中间B是overCurrentContext类型的。A、B的状态栏需要是白色的，C是需要黑色的。
vc.modalPresentationCapturesStatusBarAppearance = true，才能被传递下去。