Demo.swift

demo.swift

import RxSwift
import RxCocoa
import RxSwiftExt

class AccquiredItemViewModel: PaginationViewModel<EggProduct> {

    var selection = PublishSubject<EggProduct>()

    var preselectedProduct = PublishSubject<EggProduct>()

    // 选中的状态
    var state = BehaviorSubject<Set<EggProduct>>(value: Set())

    override init() {
		super.init()

        self.selection
            .asObservable()
            .scan(Set<EggProduct>()) { (acc: Set<EggProduct>, item: EggProduct) in
                // 选中的逻辑，什么时候应该选中：点击对应蛋壳collectionview cell 的时候
                // 不选中的逻辑，什么时候应该不选中：(1)点击已选中的蛋壳 colelctionview 的时候
                // (2) 点进去详情把所有商品取消选中的时候
                var acc = acc
                if acc.isEmpty {
                    acc.insert(item)
                } else {
                    acc.removeAll()
                    acc.insert(item)
                }
                return acc
            }
            .startWith(Set())
            .bind(to: self.state)
            .disposed(by: disposeBag)

        let response = request
            .flatMapLatest { page in
                AppEnvironment.current.apiService.getEggProductList(type: 0, page: page).materialize()
            }
            .share(replay: 1)

        response.elements()
            .map { $0.products.first }
            .filterNil()
            .bind(to: selection)
            .disposed(by: disposeBag)

        Observable
            .combineLatest(request, response.elements(), items.asObservable()) { req, res, array in
                let responseMachines = res.products
                self.isEnd.accept(responseMachines.count < Constants.kDefaultPageLimit)
                return self.pageIndex == Constants.kDefaultPageIndex ? responseMachines : array + responseMachines
            }
            .sample(response.elements())
            .bind(to: items)
            .disposed(by: disposeBag)

        Observable
            .merge(request.map { _ in true },
                   response.map { _ in false },
                   error.map { _ in false })
            .bind(to: loading)
            .disposed(by: disposeBag)

        response
            .errors()
            .requestErrors()
            .bind(to: error)
            .disposed(by: disposeBag)
    }
}