Support for UICollectionViewDelegateFlowLayout (sizeForItemAt)

[hiddely]

Are there plans to support UICollectionViewDelegateFlowLayout in some reactive way, to respond to sizes based on the data model instead of only being able to rely on indexPath?

Currently, I'm doing something like this:

    func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, sizeForItemAt indexPath: IndexPath) -> CGSize {

        guard self.events?.count ?? 0 > indexPath.section,
            let item = self.events?[indexPath.section] else {
            return .zero
        }

        switch item {
        case .comingUp(items: _):
            return // something
        case .other(month: _, items: _):
            return CGSize(width: collectionView.bounds.width, height: CompactEventCollectionViewCell.cellHeight)
        case .otherFirst(month: _, items: _):
            return CGSize(width: collectionView.bounds.width, height: CompactEventCollectionViewCell.cellHeight)
        case .tips(items: _):
            return CGSize(width: collectionView.bounds.width, height: HorizontalTipCollectionViewCell.cellHeight)
        }
    }

However, this relies on some helper local variable events, which may or may not have been updated by an observable when the delegate is called.

[cd5z]

https://github.com/RxSwiftCommunity/RxDataSources/pull/350

[lordzsolt]

A slight improvement, though not the ideal solution: Both UICollectionView and UITableView expose func model<T>(at indexPath: IndexPath) throws -> T

So you could rewrite the top part to:

guard let item = try? collectionView.rx.model(at: indexPath) as YourModel else { 
    return .zero
}