Highlight collection cell when selected - ios

Question

I am trying to highlight a selected collection cell in UICollectionView with yellow border so user can see which one is currently selected. I tried this:
- (void)collectionView:(UICollectionView *)collectionView didSelectItemAtIndexPath:(NSIndexPath *)indexPath
{
FilterCell *filterCell = (FilterCell *)[collectionView dequeueReusableCellWithReuseIdentifier:#"FilterCell" forIndexPath:indexPath];
filterCell.window.backgroundColor = [UIColor yellowColor];
filterCell.backgroundColor = [UIColor yellowColor];
NSLog(#"hello");
}
There are 2 empty pixels around UIImageView inside UICollectionViewCell so it should work but it doesn't.
It is logging "hello" but the border stays black. See this screenshot:

Answer 1

You are getting the cell in the wrong way
FilterCell *filterCell = (FilterCell *)[collectionView dequeueReusableCellWithReuseIdentifier:#"FilterCell" forIndexPath:indexPath];
will dequeue a cell which is not used right now or allocate a new one with the specified identifier.
Use
FilterCell *filterCell = (FilterCell *)[collectionView cellForItemAtIndexPath:indexPath];
instead.
Anyway a cleaner solution would be to set the backgroundView and selectedBackgroundView properties of the cell, without touching the backgroundProperty color (that will stay clear as default). In this way you can avoid the delegate method and achieve the same behavior.

Answer 2

Do a reloadItemsAtIndexPaths: there instead, then in cellForItemAtIndexPath, check if [[collectionView indexPathsForSelectedItems] containsObject:indexPath] If true, change the cell's attributes there.

Answer 3

This may help you:
cell.selectedBackgroundView = [[UIImageView alloc] initWithImage:[UIImage imageNamed:#"YOUR_FILE_NAME.png"]];

Answer 4

-This code may help you to change background colour of selected cell
-(UICollectionViewCell *)collectionView:(UICollectionView *)collectionView cellForItemAtIndexPath:(NSIndexPath *)indexPath
{
UICollectionViewCell *cell = [collectionView dequeueReusableCellWithReuseIdentifier:#"cvCell" forIndexPath:indexPath];
if (cell.selected) {
cell.backgroundColor = [UIColor blueColor]; // highlight selection
}
else
{
cell.backgroundColor = [UIColor redColor]; // Default color
}
return cell;
}
-(void)collectionView:(UICollectionView *)collectionView didSelectItemAtIndexPath:(NSIndexPath *)indexPath {
UICollectionViewCell *datasetCell =[collectionView cellForItemAtIndexPath:indexPath];
datasetCell.backgroundColor = [UIColor blueColor]; // highlight selection
}
-(void)collectionView:(UICollectionView *)collectionView didDeselectItemAtIndexPath:(NSIndexPath *)indexPath
{
UICollectionViewCell *datasetCell =[collectionView cellForItemAtIndexPath:indexPath];
datasetCell.backgroundColor = [UIColor redColor]; // Default color
}