如何观察UITabBar是否隐藏的事件？

// 添加观察者
tabBar.addObserver(self, forKeyPath: "hidden", options: .new, context: nil)

// 实现观察者的回调方法
override func observeValue(forKeyPath keyPath: String?, of object: Any?, change: [NSKeyValueChangeKey : Any]?, context: UnsafeMutableRawPointer?) {
    if keyPath == "hidden" {
        // UITabBar的hidden属性发生变化
        let tabBar = object as! UITabBar
        let isHidden = tabBar.isHidden
        // 处理隐藏状态变化的逻辑
    }
}

// 移除观察者
tabBar.removeObserver(self, forKeyPath: "hidden")

func tabBarController(_ tabBarController: UITabBarController, didSelect viewController: UIViewController) {
    let tabBar = tabBarController.tabBar
    let isHidden = tabBar.isHidden
    // 处理隐藏状态变化的逻辑
}