NSCollection re-display is slow upon reloadData

Question

jason_j OP

Created Mar ’16

Replies 1

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Participants 2

I am experiencing what looks like a slow fade in animation when I reload an NSCollection with a single cell.

I start with a small set (< 10) of data and load it.

Then I filter my data set down to one element and call reload -> I get a __slow__ refresh.

When I clear my filter, and reload then the refresh is near instantaneous.

I'm timing the call for both the filter and reload. Both are small

filter: Elapsed time is 1.99675559997559e-05 seconds.

load: Elapsed time is 0.000120997428894043 seconds.

But I am still seeing a slow refresh with the filtered set.

Any ideas? What should I be doing to diagnos this?

Thanks,

Jason

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Answer 1

Macho Man Randy Savage OP

Mar ’16

I've noticed redisplay can be a bit slow at times.

Is there anything in your collection view item set up you can optimize (your set up in)

 -(NSCollectionViewItem *)collectionView:(NSCollectionView *)collectonView itemForRepresentedObjectAtIndexPath:(NSIndexPath *)indexPath
{
   ///set up here.
 
}

In my case, I was hititng a bottleneck when shrinking the collection view items (making more cells appear on screen at once) and my thumbnail loader (which looks for a thumbnail in the method above...and possibly sends a delegate message if a thumbnail isn't cached) was loading up like 200 small thumbnails really fast, and I got a thumbnail loaded callback too many times...so there were too many calls to reloadItemsAtIndexPaths: happening too quickly and it caused the app to block.

I got around this, by not loading the images in the background if the size of the item was smaller than a certain amount, because thumbnails of that size load really quick and I could dance around the problem of reloading too many items so quickly.

0

	-(NSCollectionViewItem )collectionView:(NSCollectionView )collectonView itemForRepresentedObjectAtIndexPath:(NSIndexPath *)indexPath
	{
	///set up here.

	}