Question

这是我的代码段：

NSIndexSet *indexSet =  self.selectedIndexSet;
__block SGPhotoSelectorCell *cell;

[indexSet enumerateIndexesUsingBlock:^(NSUInteger idx, BOOL * _Nonnull stop) {

    NSLog(@"%lu", (unsigned long)idx);
    ***NSIndexPath *indexPath = [NSIndexPath indexPathWithIndex:idx];***

    cell = (SGPhotoSelectorCell *)[collectionView cellForItemAtIndexPath:indexPath];
    cell.numLabel.text = [NSString stringWithFormat:@"%lu", (unsigned long)idx];

    [collectionView selectItemAtIndexPath:indexPath animated:NO scrollPosition:UICollectionViewScrollPositionNone];
}];

出现此错误的原因是什么？

“断言失败 - [UICollectionViewData numberOfItemsBeforeSection：]”

Answer 1

我认为如果你小心这个问题很简单。请再看一下坠机的原因。 “断言失败 - [UICollectionViewData numberOfItemsBeforeSection：]”，意思是找不到该项的部分，所以你应该使用“NSIndexPath * indexPath = [NSIndexPath indexPathForItem：idx inSection：0];”替换“ * NSIndexPath indexPath = [NSIndexPath indexPathWithIndex：idx]; ”。 Okey，Bingo

什么可能导致错误“断言失败 - [UICollectionViewData numberOfItemsBeforeSection：]”？

1 个答案: