I'm having problems with [UICollectionView reloadData]
, which seems to get stuck for quite a while before it calls numberOfSectionsInCollectionView
on its delegate that I have specified. This is what happens:
The app starts with the UICollectionView immediately visible and numberOfSectionsInCollectionView
is called on the delegate, which returns the number of items in an empty array (i.e. 0) and immediately starts to download the data for the array from a web service. Once the download is complete, the data is deserialized and added to the above array, then reloadData
is called on the UICollectionView
instance. This is where the app seems to stop doing anything, and after 20-30 seconds (or sometimes up to a minute), the delegate receives a call to numberOfSectionsInCollectionView
. As soon as this call is received, the reload quickly completes.
I believe reloadData
runs in its own thread, but I've tried starting it in a separate thread to ensure that it's not any of my code blocking the process. What could reloadData
be doing while it appears stuck? Are there any intermediary delegate methods between reloadData
and numberOfSectionsInCollectionView
that I should be implementing? I thought that is the first method to be called following a reload as far as an iOS developer is concerned.
If anyone could tell me what may be going wrong, fantastic, but I'd also appreciate any tips on how to debug this!