动态显示隐藏状态栏

代码片段：

var hideStatusBar: Bool = false
override func viewDidLoad() {
    super.viewDidLoad()
    // Do any additional setup after loading the view, typically from a nib.
}

override func didReceiveMemoryWarning() {
    super.didReceiveMemoryWarning()
    // Dispose of any resources that can be recreated.
}

@IBAction func btnAction(_ sender: Any) {
    UIView.animate(withDuration: 0.5) { () -> Void in
        self.hideStatusBar = self.hideStatusBar == true ? false : true
        self.setNeedsStatusBarAppearanceUpdate()
    }
}

override var preferredStatusBarUpdateAnimation: UIStatusBarAnimation {
    return .slide
}

override var prefersStatusBarHidden: Bool {
    return hideStatusBar
}