👀 Views: 2 💬 Answers: 1 📅 Created: 2025-06-11

ios uicollectionview swift layout Swift

I'm stuck on something that should probably be simple... I'm having trouble with my `UICollectionView` in iOS 17 where the layout seems to be invalidated incorrectly when I update the content of the cells dynamically. I have a custom cell that displays an image and a label, and I'm using a simple data model. When I update the data model and call `collectionView.reloadData()`, it does not seem to reflect the changes correctly, and I often see out-of-date information. Sometimes, I even get a layout error `UICollectionViewLayoutInvalidationContext` indicating that the layout is invalidated during updates. Here's how I set up my `UICollectionView`: ```swift class MyViewController: UIViewController, UICollectionViewDataSource { var collectionView: UICollectionView! var items: [MyModel] = [] override func viewDidLoad() { super.viewDidLoad() let layout = UICollectionViewFlowLayout() collectionView = UICollectionView(frame: self.view.bounds, collectionViewLayout: layout) collectionView.dataSource = self collectionView.register(MyCustomCell.self, forCellWithReuseIdentifier: "MyCell") self.view.addSubview(collectionView) } func updateItems(newItems: [MyModel]) { self.items = newItems self.collectionView.reloadData() // Issue occurs here } func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int { return items.count } func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell { let cell = collectionView.dequeueReusableCell(withReuseIdentifier: "MyCell", for: indexPath) as! MyCustomCell cell.configure(with: items[indexPath.item]) return cell } } ``` I’ve tried calling `collectionView.performBatchUpdates` instead of `reloadData()` but still faced issues where the old cells don’t update properly. I've also ensured that the data model changes are happening on the main thread, and I verified that the items array contains the correct updated data before reloading the collection view. Still no luck. Any insights into what might be causing this layout invalidation issue or how to properly refresh the collection view? Thank you for any help! I'm working on a web app that needs to handle this.