How to change UICollectionViewCell's background outside of cell - ios

Question

How to change iOS UICollectionViewCell background outside of the cell?
For instance, I have a view controller which implements UICollectionViewDelegate method:
- (void)viewDidLoad
{
[super viewDidLoad];
[self.collectionView registerClass:[MyCollectionViewCell class] forCellWithReuseIdentifier:MY_CELL_REUSE_IDENTIFIER];
}
- (BOOL)collectionView:(UICollectionView *)collectionView shouldSelectItemAtIndexPath:(NSIndexPath *)indexPath
{
MyCollectionViewCell *cell = [collectionView dequeueReusableCellWithReuseIdentifier:MY_CELL_REUSE_IDENTIFIER forIndexPath:indexPath];
if (condition)
{
[self actionOne];
cell.backgroundColor = [UIColor redColor];
}
else
{
[self actionTwo];
cell.backgroundColor = [UIColor greenColor];
}
return YES;
}
Breakpoints inside of if (condition) statement shows, that desired lines are executed. But, sadly, cells background stays the same...
What is more, I am successfully doing practically the same thing id UICollectionViewDataSource method:
- (UICollectionViewCell *)collectionView:(UICollectionView *)collectionView cellForItemAtIndexPath:(NSIndexPath *)indexPath
{
MyCollectionViewCell *cell = [collectionView dequeueReusableCellWithReuseIdentifier:MY_CELL_REUSE_IDENTIFIER forIndexPath:indexPath];
cell.backgroundColor = [UIColor orangeColor];
}
What am I doing wrong?

Answer 1

Try cellForRowAtIndexPath in place ofdequeueReusableCellWithReuseIdentifier.
EDIT: Only in shouldSelectItemAtIndexPath.
Explanation: dequeueReusableCellWithReuseIdentifier will get you a new cell, that you change the background color of, but that cell never gets added to the table so you won't see it. When you use cellForRowAtIndexPath, you will get a cell from the table to edit.

Answer 2

This should do it:
- (void)collectionView:(UICollectionView *)collectionView didSelectItemAtIndexPath:(NSIndexPath *)indexPath {
MyCollectionViewCell *cell = [collectionView cellForItemAtIndexPath:indexPath];
if (condition)
{
[self actionOne];
cell.backgroundColor = [UIColor redColor];
}
else
{
[self actionTwo];
cell.backgroundColor = [UIColor greenColor];
}
}