performBatchUpdates:completion: 中的 reloadData: 不调用 cellForItemAtIndexPath: [英] reloadData in performBatchUpdates:completion: does not call cellForItemAtIndexPath:

问题描述

所以当我注意到这段代码时，我正在玩我的 UITableView:

So I was playing around my UITableView when I noticed that this code:

[self performBatchUpdates:^{
    [self reloadData];
} completion:^(BOOL finished) {}];

不会导致cellForItemAtIndexPath:被调用，只会调用UICollectionViewFlowLayout的sizeForItemAtIndexPath.

does not lead to cellForItemAtIndexPath: being called, only sizeForItemAtIndexPath of UICollectionViewFlowLayout is called.

有人知道为什么会这样吗?

Does anybody have any idea why this is happening?

我确切地知道 reloadData 中发生了什么，但这与此不同.

I know exactly what happens in reloadData but this is different from that.

推荐答案

来自 reloadData 的文档:不应在插入或删除行的方法中调用它，尤其是在动画块中通过调用 beginUpdates 和 endUpdates 实现."也许这也适用于 performBatchUpdates.

From the docs of reloadData: "It should not be called in the methods that insert or delete rows, especially within an animation block implemented with calls to beginUpdates and endUpdates." Perhaps this also applies to performBatchUpdates.

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