RxSwift double mapping in tableView.rx.itemSelected

Question

I want to get object from tableView.rx.itemSelected and after process it. This method return IndexPath, so I can map this value. But how to get object at index from the ViewModel?

struct ViewModel {
    var items: Observable<[Item]>
}

Approximate I expect something like this (but this flow is wrong):

tableView.rx.itemSelected
        .map { indexPath -> Item in 
        return viewModel.items.map {$0[indexPath.row]}
        }
        ..subscribe(onNext: { [unowned self] item in
        //other actions with Item object
        })
        .disposed(by: disposeBag)

I showed somewhere this possibility, but cant recollect it. Have you some idea how to do it?

Why don't you just return `viewModel.items[indexPath.row]` in `map` function? — Nikita Ermolenko, Oct 02 '17 at 12:11
@NikitaErmolenko In this case I get error: Type 'Observable<[Item]>' has no subscript members — biloshkurskyi.ss, Oct 03 '17 at 09:17

score 41 · Accepted Answer · answered Jan 09 '18 at 15:06

41

If you need both indexPath and the model you could combine the 2 methods and transform them in only one observable sequence:

Observable
    .zip(tableView.rx.itemSelected, tableView.rx.modelSelected(String.self))
    .bind { [unowned self] indexPath, model in
        self.tableView.deselectRow(at: indexPath, animated: true)
        print("Selected " + model + " at \(indexPath)")
    }
    .disposed(by: disposeBag)

answered Jan 09 '18 at 15:06

Eduard

620
9
21

is not optimal solution, because https://stackoverflow.com/a/60926473/7104327 Here – headstream Mar 30 '20 at 08:52

score 10 · Answer 2 · answered Oct 04 '17 at 08:11

10

RxCocoa has 2 methods:

public var itemSelected: ControlEvent<IndexPath> { get } which returns IndexPath of selected item
and
public func modelSelected<T>(_ modelType: T.Type) -> ControlEvent<T> which returns the model element
In accordance to your example it will look:

    tableView.rx.modelSelected(Item.self)
        .subscribe(onNext: { [weak self] item in
            // other actions with Item object
        }).addDisposableTo(disposeBag)

answered Oct 04 '17 at 08:11

Ihar Katkavets

1,510
14
25

Thanks for your comment. You are right about 2nd flow. I have used it but I want to increase my understanding. Therefore itemSelected processing is asked. – biloshkurskyi.ss Oct 04 '17 at 09:37

score 2 · Answer 3 · answered Mar 27 '19 at 21:10

Also I have found other way add do(onNext:{...}) after itemSelected command:

tableView.rx
    .itemSelected
    .do(onNext: { [unowned self] indexPath in
        self.tableView.deselectRow(at: indexPath, animated: false)
    })
    .map { indexPath -> Item in 
        return viewModel.items.map {$0[indexPath.row]}
    }
    .subscribe(self.viewModel.reviewTimeAction.inputs)
    .disposed(by: disposeBag)

RxSwift double mapping in tableView.rx.itemSelected

3 Answers3