I am using RxDatasources to create my datasource. Later on, I configure cells in my view controller. The thing is, cause headers/footers has nothing with datasource (except we can set a title, but if we use custom header footer, this title will be overriden).
Now, this is how I configure my tableview cells:
private func observeDatasource(){
let dataSource = RxTableViewSectionedAnimatedDataSource<ConfigStatusSectionModel>(
configureCell: { dataSource, tableView, indexPath, item in
if let cell = tableView.dequeueReusableCell(withIdentifier: ConfigItemTableViewCell.identifier, for: indexPath) as? BaseTableViewCell{
cell.setup(data: item.model)
return cell
}
return UITableViewCell()
})
botConfigViewModel.sections
.bind(to: tableView.rx.items(dataSource: dataSource))
.disposed(by: disposeBag)
}
now cause
dataSource.titleForHeaderInSection = { dataSource, index in
return dataSource.sectionModels[index].model
}
... won't work, cause I want to load a custom header and populate it with data from RxDatasource, I wonder what would be a proper way to:
Here is my view model:
class ConfigViewModel{
private let disposeBag = DisposeBag()
let sections:BehaviorSubject<[ConfigStatusSectionModel]> = BehaviorSubject(value: [])
func startObserving(){
let observable = getDefaults()
observable.map { conditions -> [ConfigStatusSectionModel] in
return self.createDatasource(with: conditions)
}.bind(to: self.sections).disposed(by: disposeBag)
}
private func getDefaults()->Observable<ConfigDefaultConditionsModel> {
return Observable.create { observer in
FirebaseManager.shared.getConfigDefaults { conditions in
observer.onNext(conditions!)
} failure: { error in
observer.onError(error!)
}
return Disposables.create()
}
}
private func createDatasource(with defaults:ConfigDefaultConditionsModel)->[ConfigStatusSectionModel]{
let firstSectionItems = defaults.start.elements.map{ConfigItemModel(item: $0, data: nil)}
let firstSection = ConfigStatusSectionModel(model: defaults.start.title, items: firstSectionItems.compactMap{ConfigCellModel(model: $0)})
let secondSectionItems = defaults.stop.elements.map{ConfigItemModel(item: $0, data: nil)}
let secondSection = ConfigStatusSectionModel(model: defaults.stop.title, items: secondSectionItems.compactMap{ConfigCellModel(model: $0)})
let sections:[ConfigStatusSectionModel] = [firstSection, secondSection]
return sections
}
}
Now what I was able to do, is to set a tableview delegate, like this:
tableView.rx.setDelegate(self).disposed(by: disposeBag)
and then to implement appropriate delegate method(s) to create / return custom header:
extension BotConfigViewController: UITableViewDelegate {
func tableView(_ tableView: UITableView,
viewForHeaderInSection section: Int) -> UIView? {
guard let header = tableView.dequeueReusableHeaderFooterView(
withIdentifier: ConfigSectionTableViewHeader.identifier)
as? ConfigSectionTableViewHeader
else {
return nil
}
return header
}
func tableView(_ tableView: UITableView, heightForHeaderInSection section: Int) -> CGFloat {
return UITableView.automaticDimension
}
func tableView(_ tableView: UITableView, estimatedHeightForHeaderInSection section: Int) -> CGFloat {
return 40
}
}
How to populate my custom header with data from my datasource? I don't want to do things like switch (section){...}, cause then its completely not in sync with a datasource, but rather manually, and if datasource changes, it won't affect on header configuration automatically.
Here are my model structs:
typealias ConfigStatusSectionModel = AnimatableSectionModel<String, ConfigCellModel>
struct ConfigItemData {
let conditionsLink:String?
let iconPath:String?
}
struct ConfigItemModel {
let item:OrderConditionModel
let data:ConfigItemData?
}
struct ConfigCellModel : Equatable, IdentifiableType {
static func == (lhs: ConfigCellModel, rhs: ConfigCellModel) -> Bool {
return lhs.model.item.symbol == rhs.model.item.symbol
}
var identity: String {
return model.item.symbol
}
let model: ConfigItemModel
}
I tried to use this but I wasn't able to make it work completely, cause I guess I wasn't providing custom header in a right way/moment.
The fundamental issue here is that tableView(_:viewForHeaderInSection:) is a pull based method and Rx is designed for push based systems. Obviously it can be done. After all, the base library did it for tableView(_:cellForRowAt:) but it's quite a bit more complex. You can follow the same system that the base library uses for the latter function.
Below is such a system. It can be used like this:
source
.bind(to: tableView.rx.viewForHeaderInSection(
identifier: ConfigSectionTableViewHeader.identifier,
viewType: ConfigSectionTableViewHeader.self
)) { section, element, view in
view.setup(data: element.model)
}
.disposed(by: disposeBag)
Here is the code that makes the above possible:
extension Reactive where Base: UITableView {
func viewForHeaderInSection<Sequence: Swift.Sequence, View: UITableViewHeaderFooterView, Source: ObservableType>
(identifier: String, viewType: View.Type = View.self)
-> (_ source: Source)
-> (_ configure: @escaping (Int, Sequence.Element, View) -> Void)
-> Disposable
where Source.Element == Sequence {
{ source in
{ builder in
let delegate = RxTableViewDelegate<Sequence, View>(identifier: identifier, builder: builder)
base.rx.delegate.setForwardToDelegate(delegate, retainDelegate: false)
return source
.concat(Observable.never())
.subscribe(onNext: { [weak base] elements in
delegate.pushElements(elements)
base?.reloadData()
})
}
}
}
}
final class RxTableViewDelegate<Sequence, View: UITableViewHeaderFooterView>: NSObject, UITableViewDelegate where Sequence: Swift.Sequence {
let build: (Int, Sequence.Element, View) -> Void
let identifier: String
private var elements: [Sequence.Element] = []
init(identifier: String, builder: @escaping (Int, Sequence.Element, View) -> Void) {
self.identifier = identifier
self.build = builder
}
func pushElements(_ elements: Sequence) {
self.elements = Array(elements)
}
func tableView(_ tableView: UITableView, viewForHeaderInSection section: Int) -> UIView? {
guard let view = tableView.dequeueReusableHeaderFooterView(withIdentifier: identifier) as? View else { return nil }
build(section, elements[section], view)
return view
}
}