I have a gallery in my app utilizing a UICollectionView
. The cells are approximately 70,70 size. I am using ALAssets
from the ALAssetLibrary
in the gallery which I have stored in a list.
I am using the usual pattern for populating the cells:
-(UICollectionViewCell*)collectionView:(UICollectionView *)collectionView cellForItemAtIndexPath:(NSIndexPath *)indexPath
{
mycell = [collectionView dequeueReusableCellWithReuseIdentifier:cellIdentifier forIndexPath:indexPath];
mycell.imageView.image = [[UIImage imageWithCGImage:[alassetList objectAtIndex:indexpath.row] thumbnail]];
return mycell;
}
My gallery is scrolling choppy. I don't understand why this is. I've tried adding a NSCache to cache the thumbnail images (thinking maybe creating the images was expensive) but this did not help for the performance.
I would expect the UI to be as buttery as the stock app.
I am now suspecting it may be something in the UICollectionViewCell prepareForReuse
that may be holding up the dequeueReusableCellWithReuseIdentifier
method but using instruments I was not able to find this.
Any other thing that may be be causing this? Is there a "faster" way to prepare the UICollectionViewCell
or to dequeue
them in a faster fashion?
So anybody having scrolling issues should do this
add these 2 lines after your dequeue
cell.layer.shouldRasterize = YES;
cell.layer.rasterizationScale = [UIScreen mainScreen].scale;