RxSwift DataSource configureCell not able to assign function - ios

Question

I am trying to use RxSwift/RxDataSource with TableView but I am not able to assign configureCell with an existing function. Code below:
import UIKit
import RxSwift
import RxCocoa
import RxDataSources
class BaseTableViewController: UIViewController {
// datasources
let dataSource = RxTableViewSectionedReloadDataSource<TableSectionModel>()
let sections: Variable<[TableSectionModel]> = Variable<[TableSectionModel]>([])
let disposeBag: DisposeBag = DisposeBag()
// components
let tableView: UITableView = UITableView()
override func viewDidLoad() {
super.viewDidLoad()
setupUI()
setDataSource()
}
func setupUI() {
attachViews()
}
func setDataSource() {
tableView.delegate = nil
tableView.dataSource = nil
sections.asObservable()
.bindTo(tableView.rx.items(dataSource: dataSource))
.addDisposableTo(disposeBag)
dataSource.configureCell = cell
sectionHeader()
}
func cell(ds: TableViewSectionedDataSource<TableSectionModel>, tableView: UITableView, indexPath: IndexPath, item: TableSectionModel.Item) -> UITableViewCell! {
return UITableViewCell()
}
func sectionHeader() {
}
}
Xcode throws the following error:
/Users/.../BaseTableViewController.swift:39:36: Cannot assign value of type '(TableViewSectionedDataSource, UITableView, IndexPath, TableSectionModel.Item) -> UITableViewCell!' to type '(TableViewSectionedDataSource, UITableView, IndexPath, TableSectionModel.Item) -> UITableViewCell!'
the error is thrown at line
dataSource.configureCell = cell
Do you have any idea?
Thanks

Answer 1

You just need to remove ! from return type UITableViewCell! of your cell method.
func cell(ds: TableViewSectionedDataSource<TableSectionModel>, tableView: UITableView, indexPath: IndexPath, item: TableSectionModel.Item) -> UITableViewCell {
return UITableViewCell()
}
In this way your function became type compatible with type expected by RxDataSource's configureCell property:
public typealias CellFactory = (TableViewSectionedDataSource<S>, UITableView, IndexPath, I) -> UITableViewCell
I, personally, prefer the following syntax for initialising configureCell:
dataSource.configureCell = { (_, tableView, indexPath, item) in
let cell = tableView.dequeueReusableCell(withIdentifier: "cell", for: indexPath)
// Your configuration code goes here
return cell
}