Looping through all cells in UICollectionView

Question

I have a UICollectionView and i want to add animation to each cell.

Currently I'm using

for(UICollectionView *cell in collectionView.visibleCells){
  //add animation to cell here
}

But that only applies the animation to the visible cells and as soon as i scroll down and the cell is no longer visible the animation stops.

How do i loop through all the cells in the UICollectionView?

Solution

I would go about this in a different way, probably. If you want the cells to animate, you could set a property shouldAnimate = YES. Then in your collectionView:cellForItemAtIndexPath: check that property and apply the animation if needed (or remove it).

After setting the property, reload only the visibleCells: [collectionView reloadItemsAtIndexPaths:collectionView.indexPathsForVisibleItems].

Now, since the animation is provided when a cell is requested through the Datasource-Protocol, you also get the animation when you scroll.

Comments

[user1838169]

Wow that's brilliant and works like a charm, thanks so much :)

[Juan González]

Hi, one (silly) question. Does the reloadItemsAtIndexPaths go in the same collectionView:cellForItemAtIndexPath: just after checking the property?

[fguchelaar]

No, put it in the handler for a button-press for example. Placing it in a collectionView:cellForItemAtIndexPath: would put your code in a loop. not recommended.

[Jon Madison]

To be clear, you'll want to set the property on the object in the collection that serves as the data source for your collectionview.