Overriding layoutAttributesForElementsInRect in UICollectionViewFlowLayout issue

Question

I want to create a custom UICollectionViewFlowLayout to change the way the headers and cells are displayed on the collection view. I subclassed UICollectionViewFlowLayout and overridden the layoutAttributesForElementsInRect method where I create my custom positioned UICollectionViewLayoutAttributes objects. The thing is that I am not using [super layoutAttributesForElementsInRect:(CGRect)rect] to generate the UICollectionViewLayoutAttributes and because of that my screen is blank. If I use the [super layoutAttributesForElementsInRect:(CGRect)rect] method to get the UICollectionViewLayoutAttributes, the collection view is displayed but in the default way.

I am creating my UICollectionViewLayoutAttributes using this code:

UICollectionViewLayoutAttributes *cell = [UICollectionViewLayoutAttributes
                    layoutAttributesForCellWithIndexPath:[NSIndexPath indexPathForRow:item inSection:section]];
[cell setAlpha:self.cellOpacity];
[cell setHidden:NO];
[cell setSize:self.itemSize];
[cell setZIndex:self.cellZIndex];
[cell setFrame:CGRectMake ((self.itemSize.width * item) + self.cellPadding,
                    (section * self.itemSize.height) + self.cellPadding,
                    self.itemSize.width,
                    self.itemSize.height)];

[itemsLayoutAttributes addObject:cell];

Is something wrong with the fact that I am creating the UICollectionViewLayoutAttributes manually and not using the ones created by the super method? What do you think I am doing wrong?

Thank you in advance!

check a similar answer that is all about manipulating UICollectionViewFlowLayout: http://stackoverflow.com/questions/19712201/ios-uicollectionview-default-flow-fill-rows-from-right-to-left/19923873#19923873 you can +1 if it helps :) — Raz, Jan 14 '14 at 09:22
you can also try this one: http://stackoverflow.com/questions/19474667/uicollectionview-cell-starting-margin these are all working examples :) — Raz, Jan 14 '14 at 09:25
Thank you very much Raz but I found the issue, you can read it below and it is embarrassing.. I know.. — Cata, Jan 14 '14 at 17:42

score 2 · Accepted Answer · answered Jan 14 '14 at 17:40

Actually it seems that the only thing I was doing wrong was that I wasn't careful enough to see that the opacity was set to 0 :( .

It seems that my layout now looks alright and indeed one can override layoutAttributesForElementsInRect method to create and not only edit the UICollectionViewLayoutAttributes of that flow layout.

Overriding layoutAttributesForElementsInRect in UICollectionViewFlowLayout issue

1 Answers1