ios 防止scrollerview 被遮挡

  //MARK:防止scroller被遮挡

    func extendedLayout() ->Void{

        self.edgesForExtendedLayout = UIRectEdge.init(rawValue: 0)

        self.extendedLayoutIncludesOpaqueBars = false

        self.modalPresentationCapturesStatusBarAppearance = false

    }