我正在尝试实现一个捕捉到点的滚动视图滚动时.
我在这里看到的所有帖子都是关于在用户结束拖动滚动条“之后”捕捉到某个点的。我想让它在拖动过程中折断。
到目前为止，我已经用它来停止拖动后的惯性，并且效果很好：
func scrollViewWillEndDragging(scrollView: UIScrollView, withVelocity velocity: CGPoint, targetContentOffset: UnsafeMutablePointer<CGPoint>) {
targetContentOffset.memory = scrollView.contentOffset
}
我尝试了这个，但没有按预期工作：
var scrollSnapHeight : CGFloat = myScrollView.contentSize.height/10
滚动视图DidScroll：
func scrollViewDidScroll(scrollView: UIScrollView) {
let remainder : CGFloat = scrollView.contentOffset.y % scrollSnapHeight
var scrollPoint : CGPoint = scrollView.contentOffset
if remainder != 0 && scrollView.dragging
{
if self.lastOffset > scrollView.contentOffset.y //Scrolling Down
{
scrollPoint.y += (scrollSnapHeight - remainder)
NSLog("scrollDown")
}
else //Scrolling Up
{
scrollPoint.y -= (scrollSnapHeight - remainder)
}
scrollView .setContentOffset(scrollPoint, animated: true)
}
self.lastOffset = scrollView.contentOffset.y;
}
这种方法将启用/禁用scrollEnabled的财产UIScrollView.
当scrollView滚动到给定范围之外时scrollSnapHeight, make scrollEnabled to false。这将停止滚动。然后再次启用滚动以进行下一次拖动。
extension ViewController: UIScrollViewDelegate {
func scrollViewDidScroll(scrollView: UIScrollView) {
if scrollView.contentOffset.y > lastOffset + scrollSnapHeight {
scrollView.scrollEnabled = false
} else if scrollView.contentOffset.y < lastOffset - scrollSnapHeight {
scrollView.scrollEnabled = false
}
}
func scrollViewDidEndDragging(scrollView: UIScrollView, willDecelerate decelerate: Bool) {
guard !decelerate else {
return
}
setContentOffset(scrollView)
}
func scrollViewWillBeginDecelerating(scrollView: UIScrollView) {
setContentOffset(scrollView)
}
}
func setContentOffset(scrollView: UIScrollView) {
let stopOver = scrollSnapHeight
var y = round(scrollView.contentOffset.y / stopOver) * stopOver
y = max(0, min(y, scrollView.contentSize.height - scrollView.frame.height))
lastOffset = y
scrollView.setContentOffset(CGPointMake(scrollView.contentOffset.x, y), animated: true)
scrollView.scrollEnabled = true
}
本文内容由网友自发贡献，版权归原作者所有，本站不承担相应法律责任。如您发现有涉嫌抄袭侵权的内容，请联系:hwhale#tublm.com(使用前将#替换为@)
