How would I get reference to my custom collection view cell inside the method that declares the GCSize?

问题

I have a collection view with custom view cells..

I am trying to get the reference of the cell where it's defining the height:

- (CGSize)collectionView:(UICollectionView *)collectionView layout:(UICollectionViewLayout*)collectionViewLayout sizeForItemAtIndexPath:(NSIndexPath *)indexPath
{

    CGRect screenBound = [[UIScreen mainScreen] bounds];
    CGSize screenSize = screenBound.size;
    CGFloat screenWidth = screenSize.width;

    MyCustomCell* cell = [collectionView dequeueReusableCellWithReuseIdentifier:DequeueMyCustomReusableCell forIndexPath:indexPath];

    return CGSizeMake(screenWidth, [cell calculatedHeight]);
}

This does not work.. What should I do?

Nor does this:

MyCustomCell *cell = (MyCustomCell *)[collectionView cellForItemAtIndexPath:indexPath];

来源：https://stackoverflow.com/questions/30402620/how-would-i-get-reference-to-my-custom-collection-view-cell-inside-the-method-th