怀疑我在下面做一些根本错误的事情...我有一个水平的collectionview，拖动后我想将最近的单元格捕捉到中心。但是我的结果无法预测...我在这里做错了什么？
func scrollViewDidEndDragging(scrollView: UIScrollView, willDecelerate decelerate: Bool) {
// Find collectionview cell nearest to the center of collectionView
// Arbitrarily start with the last cell (as a default)
var closestCell : UICollectionViewCell = collectionView.visibleCells()[0];
for cell in collectionView!.visibleCells() as [UICollectionViewCell] {
let closestCellDelta = abs(closestCell.center.x - collectionView.bounds.size.width/2.0)
let cellDelta = abs(cell.center.x - collectionView.bounds.size.width/2.0)
if (cellDelta < closestCellDelta){
closestCell = cell
}
}
let indexPath = collectionView.indexPathForCell(closestCell)
collectionView.scrollToItemAtIndexPath(indexPath!, atScrollPosition: UICollectionViewScrollPosition.CenteredHorizontally, animated: true)
}
最佳答案
原来我的原始代码缺少collecitonview内容偏移量的说明。另外，我将居中位置移到了scrollViewDidEndDecelerating回调中。我已经修改了原始代码，并将其包含在下面。
func scrollViewDidEndDecelerating(scrollView: UIScrollView) {
// Find collectionview cell nearest to the center of collectionView
// Arbitrarily start with the last cell (as a default)
var closestCell : UICollectionViewCell = collectionView.visibleCells()[0];
for cell in collectionView!.visibleCells() as [UICollectionViewCell] {
let closestCellDelta = abs(closestCell.center.x - collectionView.bounds.size.width/2.0 - collectionView.contentOffset.x)
let cellDelta = abs(cell.center.x - collectionView.bounds.size.width/2.0 - collectionView.contentOffset.x)
if (cellDelta < closestCellDelta){
closestCell = cell
}
}
let indexPath = collectionView.indexPathForCell(closestCell)
collectionView.scrollToItemAtIndexPath(indexPath!, atScrollPosition: UICollectionViewScrollPosition.CenteredHorizontally, animated: true)
}
关于ios - 检测最接近collectionview中心的collectionviewcell，我们在Stack Overflow上找到一个类似的问题：https://stackoverflow.com/questions/32878297/