iOS swift 滑动隐藏Tab和导航栏

1、滑动的时候先获取底部tab，利用UIView.animate设置滑动退出的动画效果。

2、滑动的时候获取顶部的导航栏，需要根据自己的项目来，有的只是系统的导航栏，有的是自定义的导航栏。

3、注意：在隐藏底部tab的时候需要设置viewController的高度来适应tab的显示与隐藏，否则在隐藏tab之后底部会出现一个黑色区域。

4、UIView.animate数值方向的动画效果，主要根据自己的项目的布局的高度设置y坐标即可。

5、具体实现代码如下。

var complete: Bool = true

func hideTabNav(hidden:Bool, animated: Bool){
        guard let tabBar = self.tabBarController?.tabBar else { return; }
        if tabBar.isHidden == hidden{ return }
        let frame = tabBar.frame
        let offset = hidden ? frame.size.height : -frame.size.height
        let duration:TimeInterval = (animated ? 0.5 : 0.0)
        tabBar.isHidden = false
        self.complete = false
        //self.viewController根据自己的项目获取top viewController，并且需要根据显示与否设置                        内容高度，否则隐藏tab之后会出现底部黑边的情况
        self.viewController?.view.frame = CGRect(x: 0, y: 0, width:
        UIScreen.mf_ScreenWidth, height: UIScreen.mf_ScreenHeight)
        
        //导航栏，根据自己的项目获取到顶部导航栏的view
        self.homeViewController?.topHidden = true
        let customNavigationView = self.homeViewController?.customNavigationView
        customNavigationView?.isHidden = false
        let cnFrame = customNavigationView?.frame
        let cnOffset = hidden ? -(cnFrame?.height ?? 0) : (cnFrame?.height ?? 0)

        let bgView = self.homeViewController?.bgView
        bgView?.isHidden = false
        let bgFrame = bgView?.frame
        let bgOffset = hidden ? -(bgFrame?.height ?? 0) : (bgFrame?.height ?? 0)
        
        UIView.animate(withDuration: duration, animations: {
            tabBar.frame = frame.offsetBy(dx: 0, dy: offset)
            customNavigationView?.frame = (cnFrame?.offsetBy(dx: 0, dy: cnOffset))!
            bgView?.frame = (bgFrame?.offsetBy(dx: 0, dy: bgOffset))!
        }, completion: { (true) in
            tabBar.isHidden = hidden
            customNavigationView?.isHidden = hidden
            bgView?.isHidden = hidden
            self.complete = true
            if hidden {
                self.homeViewController?.view.frame = CGRect(x: 0, y: 0, width:                 UIScreen.mf_ScreenWidth, height: UIScreen.mf_ScreenHeight)
            } else {
                self.homeViewController?.view.frame = CGRect(x: 0, y: 0, width:                 UIScreen.mf_ScreenWidth, height: UIScreen.mf_ScreenHeight-                tabBar.frame.height)
            }
        })
    }