Change a view inside of UICollectionViewCell when tapped not working - ios

Question

I have a list of user avatars inside of a UICollectionViewCell. When the user taps on one, I'd like to add the selected item to a collection as well as highlight it to indicate it's been tapped.
Unfortunately the UI doesn't seem to update. Any ideas?
Initially I load the images and set them to be rounded. I can even set the border color, if I want, but for now I set it to clear. This all works upon loading the cells:
func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
let cell = collectionView.dequeueReusableCell(withReuseIdentifier: "cell", for: indexPath as IndexPath) as! UICollectionViewCell
// Configure the cell
let member: UserProfile = groupMembers[indexPath.item]
let imgAvatar = cell.viewWithTag(2) as! UIImageView
imgAvatar.layer.cornerRadius = contactAvatar.frame.size.width / 2
imgAvatar.clipsToBounds = true
imgAvatar.contentMode = UIViewContentMode.scaleAspectFill
imgAvatar.layer.borderWidth = 2.0
imgAvatar.layer.borderColor = UIColor.clear.cgColor
imgAvatar.layer.cornerRadius = 30.0
let downloadURL = NSURL(string: member.avatarUrl)!
imgAvatar.af_setImage(withURL: downloadURL as URL)
return cell
}
And now here is the code that executes when you tap on any given UIImageView in the collection, but it does not seem to update the image:
///Fired when tapped on an image of a person
func collectionView(_ collectionView: UICollectionView, didSelectItemAt indexPath: IndexPath) {
let cell = collectionView.dequeueReusableCell(withReuseIdentifier: "cell", for: indexPath as IndexPath) as! UICollectionViewCell
let tappedUser: UserProfile = groupMembers[indexPath.item]
let imgAvatar = cell.viewWithTag(2) as! UIImageView
..add item to collection, etc..
//Update imageview to indicate it's been tapped.
DispatchQueue.main.async {
contactAvatar.layer.cornerRadius = contactAvatar.frame.size.width / 2
imgAvatar.clipsToBounds = true
imgAvatar.contentMode = UIViewContentMode.scaleAspectFill
imgAvatar.layer.borderWidth = 2.0
imgAvatar.layer.cornerRadius = 30.0
imgAvatar.layer.borderColor = UIcolor.blue.cgColor
}
}
}
Running this code, it hits the breakpoint to indicate I've tapped on the item, but it does not update the UI. I'm convinced there is a thread / ui issue where the collection view isn't "redrawing" the changes I've made to the image. Maybe I can't change around the appearances of a view inside of a collection?
Thanks in advance for any insight.

Answer 1

Your didSelect is not correct. Get the cell from the collection view.
cellForItem
///Fired when tapped on an image of a person
func collectionView(_ collectionView: UICollectionView, didSelectItemAt indexPath: IndexPath) {
let cell = collectionView.cellForItem(at:indexPath) as! UICollectionViewCell
let tappedUser: UserProfile = groupMembers[indexPath.item]
let imgAvatar = cell.viewWithTag(2) as! UIImageView
..add item to collection, etc..
//Update imageview to indicate it's been tapped.
DispatchQueue.main.async {
contactAvatar.layer.cornerRadius = contactAvatar.frame.size.width / 2
contactAvatar.clipsToBounds = true
contactAvatar.contentMode = UIViewContentMode.scaleAspectFill
contactAvatar.layer.borderWidth = 2.0
contactAvatar.layer.cornerRadius = 30.0
contactAvatar.layer.borderColor = UIcolor.blue.cgColor
}
}
}
Using mobile so let me know if it does not work.

Answer 2

The code which you have written to to get instance of cell is not correct please use below line of code and rest all seems correct hope by changing this line will work.
let cell = collectionView.cellForItem(at:indexPath) as! UICollectionViewCell