ios - 在 UICollectionView 中向下滚动时如何自动调用 PFQuery

Question

我有一个UICollectionView其中每个单元格包含一个PFObject. 由于每个对象可能有数百个这样的对象UICollectionView，我不想一次查询所有对象，而是只调用有限的数量，然后在用户滚动到最后时自动调用更多对象（有点像无休止的滚动许多网络应用程序使用）。

将PFQuery支持这些类型的呼叫，如果是这样，我将如何能够连续自动呼叫？

谢谢！

Answer 1

Perhaps something like this to get you on the right track:

- (void)scrollViewDidScroll:(UIScrollView *)scrollView {

    float scrollViewHeight = scrollView.frame.size.height;
    float scrollContentSizeHeight = scrollView.contentSize.height;

    else if (scrollView.contentOffset.y <= 0) {
        // then we are at the top
    }
    else if (scrollView.contentOffset.y + scrollViewHeight >= scrollContentSizeHeight) {
        // then we are at the bottom - query new results


    }

}

I don't think you'd have to add anything for it to call as long as your controller is already your collectionView's delegate.