swift tabbar 跳转子页面时隐藏方法

//注意：在push后设置self.hidesBottomBarWhenPushed=NO;
//这样back回来的时候，tabBar会恢复正常显示。

let detailCtrl = ScanViewController(nibName: "ScanViewController", bundle: nil);
        //detailCtrl.hidesBottomBarWhenPushed = true
        self.hidesBottomBarWhenPushed = true
        self.navigationController?.pushViewController(detailCtrl, animated: true)
        self.hidesBottomBarWhenPushed = false