UIScrollView 自适应所有布局

1. 准备contentView

必备四行代码 ，配置contentView，以后所有的view都加入到contenview 而不是view

 let contentView = UIView() // 必备
 let scrollView = UIScrollView()
 view.addSubview(scrollView)
 scrollView.addSubview(contentView)

2.给Scrollview contentView 设置约束

   scrollView.snp.makeConstraints { make in
            make.top.equalTo(navBar.bottomLine)
            make.left.right.equalTo(view)
            make.bottom.equalTo(view).offset(-kBottomMargin)
        }
        
    contentView.snp.makeConstraints { make in
            make.edges.equalTo(scrollView)
            make.width.equalTo(scrollView)
//            make.bottom.equalTo(bottomCollectionView.snp.bottom).offset(30)
        }

3.在整个布局中的最后一个View自动约束完成后，增加contentView 的bottom 布局约束

contentView.snp.makeConstraints { make in
            make.bottom.equalTo(bottomCollectionView.snp.bottom).offset(10)
        }