问题描述
如何在VC中向上/向下滚动/滑动方向？
How can I get the scroll/swipe direction for up/down in a VC?
我想在我的VC中添加一个UIScrollView或其他东西，如果用户向上或向下滑动/滚动，然后隐藏/显示 UIView （取决于它是向上/向下手势）。
I want to add a UIScrollView or something else in my VC that can see if the user swipes/scrolls up or down and then hide/show a UIView depending if it was an up/down gesture.
推荐答案
如果您使用 UIScrollView ，那么您可以从功能。您需要保存最后一个位置（ contentOffset ）和它的更新方式如下：
If you use an UIScrollView then you can take benefit from the scrollViewDidScroll: function. You need to save the last position (the contentOffset) it have and the update it like in the following way:
// variable to save the last position visited, default to zero
private var lastContentOffset: CGFloat = 0
func scrollViewDidScroll(scrollView: UIScrollView!) {
if (self.lastContentOffset > scrollView.contentOffset.y) {
// move up
}
else if (self.lastContentOffset < scrollView.contentOffset.y) {
// move down
}
// update the new position acquired
self.lastContentOffset = scrollView.contentOffset.y
}
还有其他方法，当然这是一个给他们。
There are other ways of do it of course this is one to them.
我希望这能帮助你。
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