UICollectionView - insertItems(at: indexPath) not working

Question

I have an array with some elements in it which my UICollectionView displays. I then go and fetch more elements and append it to my array. I want to then tell the UICollectionView that elements have been added to the datasource and to update the UI.

I tried this but it is not working:

// Add more data to my existing array
myArray.append(contentsOf: moreElements)
let indexPath = [IndexPath(row: myArray.count-1, section: 0)]
myCollectionView.insertItems(at: indexPath)

I get this error but I am not sure if I am doing something wrong.

EDIT: I do NOT want to use myCollectionView.reloadData()

Answer 1

Your issue is that you need an IndexPath for each item you are adding to the collection view. You add multiple objects to myArray but then you only pass one IndexPath to insertItems. And this is the cause of the error.

Try the following:

var paths = [IndexPath]()
for item in 0..<moreElements.count {
    let indexPath = IndexPath(row: item + myArray.count, section: 0)
    paths.append(indexPath)
}

myArray.append(contentsOf: moreElements)
myCollectionView.insertItems(at: paths)