Refreshing or reloading data on just single object inside a collectionViewCell - swift

Question

i'm trying to update just one single object inside my costumViewCell,
i've tried collectionView.reloadItems(at: [IndexPath]), but this method updates my entire cell, which results to a very jittering animations.
here is a sample code of my collectionView cell,
class MyCollectionViewCell: UICollectionViewCell {
#IBOutlet weak var buttonA: UIButton!
#IBOutlet weak var buttonB: UIButton!
var myButtonTitle: String? {
didSet{
if let title = myButtonTitle {
self.buttonA.setTitle(title, for: .normal)
}
}
}
var buttonActionCallBack: (()->()?)
override func awakeFromNib() {
super.awakeFromNib()
self.animation()
buttonA.addTarget(self, action: #selector(buttonACallBack), for: .touchUpInside)
}
#objc fileprivate func buttonACallBack() {
self.buttonActionCallBack?()
}
fileprivate func animation() {
UIView.animate(withDuration: 1.0) {
self.buttonA.transform = CGAffineTransform(translationX: 20, y: 20)
self.buttonB.transform = CGAffineTransform(translationX: 20, y: 20)
}
}
}
here is my DataSource method.
func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
let cell = collectionView.dequeueReusableCell(withReuseIdentifier: "Cell", for: indexPath) as! MyCollectionViewCell
let item = mainList[indexPath.row]
collectionView.reloadItems(at: <#T##[IndexPath]#>)
cell.buttonActionCallBack = {
() in
//Do Stuff and Update Just ButtonA Title
}
return cell
}
cheers.

Answer 1

The jittering animation occurs because of this collectionView.reloadItems(at: [IndexPath]) line written inside cellForItemAt which is really wrong approach because cellForItemAt called many a times leads to infinite loop of reloading IndexPath's. Instead of that, you just reload only that part which is necessary when action occurs.
func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
let cell = collectionView.dequeueReusableCell(withReuseIdentifier: "Cell", for: indexPath) as! MyCollectionViewCell
let item = mainList[indexPath.row]
//collectionView.reloadItems(at: <#T##[IndexPath]#>) #removed
cell.buttonActionCallBack = {
() in
//Do Stuff and Update Just ButtonA Title
collectionView.reloadItems(at: [indexPath]) //Update after the change occurs to see the new UI updates
}
return cell
}