UICollectionView and selected UICollectionViewCell - ios

Question

I'm trying to do a simple UICollectionView with a custom cell composed of an UIImageView and an UIView above.
When a cell is not selected, the UIView on the top of the cell have is backgroundColor property set to UIColor(red: 1, green: 1, blue: 1, alpha: 0.5).
I have issues with the selection. The collectionView:didSelectItemAtIndexPath: method is called but when I change the UIView described previously, nothing happen.
Here is the code of my collectionView :
class TestCollectionViewController: UICollectionViewController
{
var items = [1, 2, 3]
let cellId = "Cell"
override func viewDidLoad()
{
self.collectionView.allowsMultipleSelection = true
self.collectionView.delaysContentTouches = false
}
override func collectionView(collectionView: UICollectionView!, numberOfItemsInSection section: Int) -> Int
{
return items.count
}
override func collectionView(collectionView: UICollectionView!, cellForItemAtIndexPath indexPath: NSIndexPath!) -> UICollectionViewCell!
{
var cell = collectionView.dequeueReusableCellWithReuseIdentifier(cellId,
forIndexPath: indexPath) as TestingCollectionViewCell
let item = items[indexPath.row]
cell.imageView.image = UIImage(named: "img")
cell.overlayView.backgroundColor = UIColor(red: 1, green: 1, blue: 1, alpha: 0.5)
return cell
}
override func collectionView(collectionView: UICollectionView!, didSelectItemAtIndexPath indexPath: NSIndexPath!)
{
var cell = collectionView.dequeueReusableCellWithReuseIdentifier(cellId,
forIndexPath: indexPath) as TestingCollectionViewCell
cell.overlayView.backgroundColor = UIColor.clearColor()
}
override func collectionView(collectionView: UICollectionView!, didDeselectItemAtIndexPath indexPath: NSIndexPath!)
{
var cell = collectionView.dequeueReusableCellWithReuseIdentifier(cellId,
forIndexPath: indexPath) as TestingCollectionViewCell
cell.overlayView.backgroundColor = UIColor(red: 1, green: 1, blue: 1, alpha: 0.5)
}
}
If this snippet is not enough, here is my project

Answer 1

You should not be dequeuing a new cell in didSelectItemAtIndexPath (or in didDeselect either) -- this is creating (or reusing) a new cell, not getting the one you selected. Use this instead,
var cell = collectionView.cellForItemAtIndexPath(indexPath)

Answer 2

To me the following code worked better (the code of rdelmar crashed sometimes, which might be a bug? in Swift):
(collectionView.cellForItemAtIndexPath(indexPath) as myCollectionViewCellType).uiBackground?.backgroundColor = UIColor.blackColor()
Edit: I forgot to mention: My collectionView-Items are based on their own class to which I cast. uiBackground is an element of that class

Answer 3

Swift 3.0
let cell = collectionView.cellForItem(at: indexPath)

Answer 4

func collectionView(collectionView: UICollectionView, didSelectItemAtIndexPath indexPath: NSIndexPath)
{
//saving index path of the image loaded from imageproperty_array
selected_imagepath = imageproperty_array[indexPath.row] as String
//saving index of the selected cell item as Int
selected_imageindex = indexPath.row
}