问题描述
如何在 VC 中获取向上/向下的滚动/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，可以查看用户是否向上或向下滑动/滚动，然后隐藏/显示 UIView 取决于它是否是向上/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
如果你使用 UIScrollView 那么你可以从 scrollViewDidScroll: 功能.您需要保存它的最后一个位置(contentOffset)并按以下方式更新它:
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
}
当然还有其他方法可以做到这一点.
There are other ways of do it of course this is one to them.
希望对你有所帮助.
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