Assertion Failure in UICollectionViewData indexPathForItemAtGlobalIndex

Question

I am using performBatchUpdates() to update my collection view, where I am doing a complete refresh, i.e. delete whatever was in it and re-insert everything.

Answer 1

I still couldn't figure out how the global index was incremented so much, but I solved my problem by inserting a temporary item in the underlying datasource array i.e. cellItems and calling [self.collectionview reloadData] in viewDidLoad().

This inserts a placeholder cell temporarily in the collection view until I trigger the actual process using performBatchUpdates().

Answer 2

I have been having the same problem.

I have tried a number of variations, but the final one that seems to work is [self.collectionView reloadData], where "self.collectionView"is the name of your collection view.

I have tried the following methods, straight from the "UICollectionView Class Reference": inserting, moving, and deleting items.

These were used at first, to "move" the item from one section to another.

• deleteItemsAtIndexPaths:

• insertItemsAtIndexPaths:

Next, I tried moveItemAtIndexPath:toIndexPath:.

They all produced the following error:

Assertion failure in -[UICollectionViewData indexPathForItemAtGlobalIndex:], /SourceCache/UIKit_Sim/UIKit-2372/UICollectionViewData.m:442

So, try the "reloadData" method.