向上滚动时使 UIScrollView 中的 UIView 粘在顶部 [英] make UIView in UIScrollView stick to the top when scrolled up

问题描述

因此，在 UITableView 中，当您有部分时，部分视图会粘在顶部，直到下一部分与它重叠，然后将其替换在顶部.我想有一个类似的效果，基本上我在我的 UIScrollView 中有一个 UIView，代表 UIView 的部分以及它何时到达顶部......我希望它留在那里而不是被抬高.我该怎么做呢?我认为这需要在 layoutSubviews 或 scrollViewDidScroll 中完成并对 UIVIew 进行操作..

So in a UITableView when you have sections the section view sticks to the top until the next section overlaps it and then it replaces it on top. I want to have a similar effect, where basically I have a UIView in my UIScrollView, representing the sections UIView and when it hits the top.. I want it to stay in there and not get carried up. How do I do this? I think this needs to be done in either layoutSubviews or scrollViewDidScroll and do a manipulation on the UIVIew..

推荐答案

要在 UIScrollView 中创建 UIView 在向上滚动时粘在顶部执行:

To create UIView in UIScrollView stick to the top when scrolled up do:

func createHeaderView(_ headerView: UIView?) {
    self.headerView = headerView
    headerViewInitialY = self.headerView.frame.origin.y
    scrollView.addSubview(self.headerView)
    scrollView.delegate = self
}

func scrollViewDidScroll(_ scrollView: UIScrollView) {
    let headerFrame = headerView.frame
    headerFrame.origin.y = CGFloat(max(headerViewInitialY, scrollView.contentOffset.y))
    headerView.frame = headerFrame
}

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