//1、創(chuàng)建一個滾動視圖
        let scrollView = UIScrollView()
        scrollView.pagingEnabled = true
        scrollView.showsHorizontalScrollIndicator = false
        view.addSubview(scrollView)
        //約束
        scrollView.snp_makeConstraints {
            [weak self]
            (make) in
            make.edges.equalTo(self!.view).inset(UIEdgeInsetsMake(64, 0, 49, 0))
        }
        
        //2、創(chuàng)建容器視圖
        let containerView = UIView.createView()
        scrollView.addSubview(containerView)
        
        //約束
        containerView.snp_makeConstraints { (make) in
            make.edges.equalTo(scrollView)
            make.height.equalTo(scrollView)
            //我們 后來，要改變 他的 寬度 （成3倍）。哪個地方不變，要把他先固定下來。
        }