关于ios:swift53-UIScrollView-动态计算-contentSize

UIScrollView 的非凡之处就在于当它遇到了 AutoLayout 之后其 contentSize 的计算规定有些非凡。
contentSize 是依据子视图的 leading/trailing/top/bottom 进行确定的

所以防止咱们手动去设置 contentSize，咱们必须投合它的规定去设置

间接上代码

       let scrollView = UIScrollView()
        
        scrollView.backgroundColor = .gray
        view.addSubview(scrollView)
        scrollView.snp.makeConstraints {(make) in
            make.edges.equalToSuperview()}
        let containerView = UIView()
        containerView.backgroundColor = .blue
        scrollView.addSubview(containerView)
        containerView.snp.makeConstraints {(make) in
            make.edges.equalToSuperview()
            make.width.equalToSuperview()}
        
        let view1 = UIView()
        view1.backgroundColor = .orange
        
        let view2 = UIView()
        view2.backgroundColor = .blue
        
        
        containerView.addSubview(view1)
        containerView.addSubview(view2)
        
        view1.snp.makeConstraints {(make) in
            make.top.equalToSuperview()
            make.width.equalToSuperview()
            make.height.equalTo(500)
        }
        
        view2.snp.makeConstraints {(make) in
            make.top.equalTo(view1.snp.bottom)
            make.bottom.equalTo(containerView.snp.bottom)
            make.leading.trailing.equalTo(containerView)
            make.width.equalToSuperview()
            make.height.equalTo(500)
        }

大略就是这意思，咱们通过一个填满的 containerView 去设置子视图，同时咱们最初一个 subview 的 bottom 肯定要与 containerView 对齐即可