swift 3:如何在不丢失高度的情况下隐藏状态栏

override var prefersStatusBarHidden: Bool {
    return true
}

override var prefersStatusBarHidden: Bool {
    return shouldHideStatusBar
}

override var preferredStatusBarUpdateAnimation: UIStatusBarAnimation {
    return .slide
}

// 在需要的地方设置shouldHideStatusBar的值
func toggleStatusBar() {
    shouldHideStatusBar = !shouldHideStatusBar
    UIView.animate(withDuration: 0.3) {
        self.setNeedsStatusBarAppearanceUpdate()
    }
}