CollectionView使用技巧

1.获取CollectionView当前显示的Cell.

• (void)scrollViewDidEndDecelerating:(UIScrollView *)scrollView {
  // 将collectionView在控制器view的中心点转化成collectionView上的坐标
  CGPoint pInView = [self.view convertPoint:self.collectionView.center toView:self.collectionView];
  // 获取这一点的indexPath
  NSIndexPath *indexPathNow = [self.collectionView indexPathForItemAtPoint:pInView];
  // 赋值给记录当前坐标的变量
  self.currentIndexPath = indexPathNow;
  // 更新底部的数据
  // ...
  }

https://blog.csdn.net/happyshaotang2/article/details/78978554