I am willing to force a reload of a collectionView when new content is fetched from a web-service while using RxSwift. I can't figure out why I don't receive an event on newContent with the following code when my onComplete closure is properly called.
class ListingView : UIView {
var newContentStream: Observable<Bool>?
let disposeBag = DisposeBag()
#IBOutlet weak var collectionView: UICollectionView!
weak var viewModel: ListingViewModel?
func bind(viewModel: ListingViewModel) {
self.viewModel = viewModel
}
func configure() {
guard let viewModel = self.viewModel else { return }
self.newContentStream = viewModel.newContent.asObservable()
self.newContentStream!.subscribeNext { _ in
self.collectionView.reloadData()
}
.addDisposableTo(self.disposeBag)
}
}
and then within my viewModel:
class ListingViewModel {
let dataSource = ListingViewDataSoure()
var newContent = Variable(false)
func mount() {
let onComplete : ([item]? -> Void) = { [weak self] items in
self?.dataSource.items = items
self?.newContent = Variable(true)
}
guard let URL = API.generateURL() else { return }
Requestor.fetchAll(onComplete, fromURL: URL)
}
}
It's because self?.newContent = Variable(true) is replacing the newContent with an entirely new Variable, after you've already subscribed to the original here:
self.newContentStream = viewModel.newContent.asObservable()
self.newContentStream!.subscribeNext { ......
That subscription in your UIView is now listening to an Observable that no one is ever going to be sending a Next event on.
Instead, you should be sending out a Next event on the current (and only) newContent Variable/Observable:
self?.newContent.value = true
You could fix it and continue to use a newContent Variable and a reloadData call, however, I wouldn't recommend doing it like this. Instead, check out RxDataSources.
Related
I'm trying to create an app to get some news from an API and i'm using Moya, RxSwift and MVVM.
This is my ViewModel:
import Foundation
import RxSwift
import RxCocoa
public enum NewsListError {
case internetError(String)
case serverMessage(String)
}
enum ViewModelState {
case success
case failure
}
protocol NewsListViewModelInput {
func viewDidLoad()
func didLoadNextPage()
}
protocol MoviesListViewModelOutput {
var newsList: PublishSubject<NewsList> { get }
var error: PublishSubject<String> { get }
var loading: PublishSubject<Bool> { get }
var isEmpty: PublishSubject<Bool> { get }
}
protocol NewsListViewModel: NewsListViewModelInput, MoviesListViewModelOutput {}
class DefaultNewsListViewModel: NewsListViewModel{
func viewDidLoad() {
}
func didLoadNextPage() {
}
private(set) var currentPage: Int = 0
private var totalPageCount: Int = 1
var hasMorePages: Bool {
return currentPage < totalPageCount
}
var nextPage: Int {
guard hasMorePages else { return currentPage }
return currentPage + 1
}
private var newsLoadTask: Cancellable? { willSet { newsLoadTask?.cancel() } }
private let disposable = DisposeBag()
// MARK: - OUTPUT
let newsList: PublishSubject<NewsList> = PublishSubject()
let error: PublishSubject<String> = PublishSubject()
let loading: PublishSubject<Bool> = PublishSubject()
let isEmpty: PublishSubject<Bool> = PublishSubject()
func getNewsList() -> Void{
print("sono dentro il viewModel!")
NewsDataService.shared.getNewsList()
.subscribe { event in
switch event {
case .next(let progressResponse):
if progressResponse.response != nil {
do{
let json = try progressResponse.response?.map(NewsList.self)
print(json!)
self.newsList.onNext(json!)
}
catch _ {
print("error try")
}
} else {
print("Progress: \(progressResponse.progress)")
}
case .error( _): break
// handle the error
default:
break
}
}
}
}
This is my ViewController, where xCode give me the following error when i try to bind to tableNews:
Expression type 'Reactive<_>' is ambiguous without more context
import UIKit
import RxSwift
import RxCocoa
class ViewController: UIViewController {
#IBOutlet weak var tableNews: UITableView!
let viewModel = DefaultNewsListViewModel()
var disposeBag = DisposeBag()
override func viewDidLoad() {
super.viewDidLoad()
}
private func setupBindings() {
viewModel.newsList.bind(to: tableNews.rx.items(cellIdentifier: "Cell")) {
(index, repository: NewsList, cell) in
cell.textLabel?.text = repository.name
cell.detailTextLabel?.text = repository.url
}
.disposed(by: disposeBag)
}
}
This is the service that get data from API:
import Moya
import RxSwift
struct NewsDataService {
static let shared = NewsDataService()
private let disposable = DisposeBag()
private init() {}
fileprivate let newsListProvider = MoyaProvider<NewsService>()
func getNewsList() -> Observable<ProgressResponse> {
self.newsListProvider.rx.requestWithProgress(.readNewsList)
}
}
I'm new at rxSwift, I followed some documentation but i'd like to know if i'm approaching in the right way. Another point i'd like to know is how correctly bind my tableView to viewModel.
Thanks for the support.
As #FabioFelici mentioned in the comments, UITableView.rx.items(cellIdentifier:) is expecting to be bound to an Observable that contains an array of objects but your NewsListViewModel.newsList is an Observable<NewsList>.
This means you either have to extract the array out of NewsList (assuming it has one) through a map. As in newsList.map { $0.items }.bind(to:...
Also, your MoviesListViewModelOutput should not be full of Subjects, rather it should contain Observables. And I wouldn't bother with the protocols, struts are fine.
Also, your view model is still very imperative, not really in an Rx style. A well constructed Rx view model doesn't contain functions that are repeatedly called. It just has a constructor (or is itself just a single function.) You create it, bind to it and then you are done.
I have a very simple project, where I want to dynamically filter content in UITableView regarding pressed index in UISegmentedControl. I'm using MVVM with RxSwift, Realm and RxDataSources. So my problem, that if I want to update content in UITableView I need to create 'special' DisposeBag, only for that purposes, and on each selection in UISegmentedControl nil it and create again. Only in this case, if I'm understand right, subscription is re-newed, and UITableView displays new results from Realm.
So is there any better way to do such operation? Without subscribing every time, when I switch tab in UISegmentedControl. Here's my code:
//ViewController
class MyViewController : UIViewController {
//MARK: - Props
#IBOutlet weak var tableView: UITableView!
#IBOutlet weak var segmentedControl: UISegmentedControl!
let dataSource = RxTableViewSectionedReloadDataSource<ItemsSection>()
let disposeBag = DisposeBag()
var tableViewBag: DisposeBag!
var viewModel: MyViewModel = MyViewModel()
//MARK: - View lifecycle
override func viewDidLoad() {
super.viewDidLoad()
self.setupRxTableView()
}
//MARK: - Setup observables
fileprivate func setupRxTableView() {
dataSource.configureCell = { ds, tv, ip, item in
let cell = tv.dequeueReusableCell(withIdentifier: "ItemCell") as! ItemTableViewCell
return cell
}
bindDataSource()
segmentedControl.rx.value.asDriver()
.drive(onNext: {[weak self] index in
guard let sSelf = self else { return }
switch index {
case 1:
sSelf.bindDataSource(filter: .active)
case 2:
sSelf.bindDataSource(filter: .groups)
default:
sSelf.bindDataSource()
}
}).disposed(by: disposeBag)
}
private func bindDataSource(filter: Filter = .all) {
tableViewBag = nil
tableViewBag = DisposeBag()
viewModel.populateApplying(filter: filter)
}).bind(to: self.tableView.rx.items(dataSource: dataSource))
.disposed(by: tableViewBag)
}
}
//ViewModel
class MyViewModel {
func populateApplying(filter: Filter) -> Observable<[ItemsSection]> {
return Observable.create { [weak self] observable -> Disposable in
guard let sSelf = self else { return Disposables.create() }
let realm = try! Realm()
var items = realm.objects(Item.self).sorted(byKeyPath: "date", ascending: false)
if let predicate = filter.makePredicate() { items = items.filter(predicate) }
let section = [ItemsSection(model: "", items: Array(items))]
observable.onNext(section)
sSelf.itemsToken = items.addNotificationBlock { changes in
switch changes {
case .update(_, _, _, _):
let section = [ItemsSection(model: "", items: Array(items))]
observable.onNext(section)
default: break
}
}
return Disposables.create()
}
}
}
Don't recall if this is breaking MVVM off the top of my head, but would Variable not be what you're looking for?
Variable<[TableData]> data = new Variable<[TableData]>([])
func applyFilter(filter: Predicate){
data.value = items.filter(predicate) //Any change to to the value will cause the table to reload
}
and somewhere in the viewController
viewModel.data.rx.asDriver().drive
(tableView.rx.items(cellIdentifier: "ItemCell", cellType: ItemTableViewCell.self))
{ row, data, cell in
//initialize cells with data
}
My expectation is to add observables on-the-fly (eg: images upload), let them start, and, when I finished dynamically enqueueing everything, wait for all observable to be finished.
Here is my class :
open class InstantObservables<T> {
lazy var disposeBag = DisposeBag()
public init() { }
lazy var observables: [Observable<T>] = []
lazy var disposables: [Disposable] = []
open func enqueue(observable: Observable<T>) {
observables.append(observable)
let disposable = observable
.subscribe()
disposables.append(disposable)
disposable
.addDisposableTo(disposeBag)
}
open func removeAndStop(atIndex index: Int) {
guard observables.indices.contains(index)
&& disposables.indices.contains(index) else {
return
}
let disposable = disposables.remove(at: index)
disposable.dispose()
_ = observables.remove(at: index)
}
open func waitForAllObservablesToBeFinished() -> Observable<[T]> {
let multipleObservable = Observable.zip(observables)
observables.removeAll()
disposables.removeAll()
return multipleObservable
}
open func cancelObservables() {
disposeBag = DisposeBag()
}
}
But when I subscribe to the observable sent by waitForAllObservablesToBeFinished() , all of them are re-executed (which is logic, regarding how Rx works).
How could I warranty that each are executed once, whatever the number of subscription is ?
While writing the question, I got the answer !
By altering the observable through shareReplay(1), and enqueuing and subscribing to this altered observable.. It works !
Here is the updated code :
open class InstantObservables<T> {
lazy var disposeBag = DisposeBag()
public init() { }
lazy var observables: [Observable<T>] = []
lazy var disposables: [Disposable] = []
open func enqueue(observable: Observable<T>) {
let shared = observable.shareReplay(1)
observables.append(shared)
let disposable = shared
.subscribe()
disposables.append(disposable)
disposable
.addDisposableTo(disposeBag)
}
open func removeAndStop(atIndex index: Int) {
guard observables.indices.contains(index)
&& disposables.indices.contains(index) else {
return
}
let disposable = disposables.remove(at: index)
disposable.dispose()
_ = observables.remove(at: index)
}
open func waitForAllObservablesToBeFinished() -> Observable<[T]> {
let multipleObservable = Observable.zip(observables)
observables.removeAll()
disposables.removeAll()
return multipleObservable
}
open func cancelObservables() {
disposeBag = DisposeBag()
}
}
I'm newer to RxSwift. I want to refresh the tableview to show new data.The first request that I can get the data. but when I pull down the tableview, the request didn't finished. I have no ideas about this? My code is belowing:
1: My viewController's code:
class RecommendViewController: UIViewController {
lazy var tableView = DefaultManager.createTableView(HomeImageCell.self,
HomeImageCell.idenfitier)
let disposeBag = DisposeBag()
lazy var viewModel = HomeViewModel()
lazy var dataSource: [HomeListDetailModel] = []
override func viewDidLoad() {
super.viewDidLoad()
viewModel.fetchRecommendList("answer_feed",0)
setupTableView()
configureRefresh()
bindDataToTableView()
}
func setupTableView() {
view.addSubview(tableView)
tableView.snp.makeConstraints { (make) in
make.edges.equalTo(0)
}
tableView.estimatedHeight(200)
}
func bindDataToTableView() {
viewModel.recommend
.observeOn(MainScheduler.instance)
.do(onNext: { [unowned self] model in
print("endAllRefresh")
self.endAllRefresh()
}, onError: { (error) in
self.endAllRefresh()
print("error = \(error)")
})
.map { [unowned self] model in
return self.handleData(model)
}.bind(to: tableView.rx.items(cellIdentifier: HomeImageCell.idenfitier , cellType: HomeImageCell.self )) { index, model, cell in
cell.updateCell(data: model)
}.disposed(by: disposeBag)
}
func configureRefresh() {
tableView.mj_header = MJRefreshNormalHeader(refreshingBlock: { [unowned self] in
let model = self.dataSource[0]
self.viewModel.fetchRecommendList("answer_feed",model.behot_time)
})
tableView.mj_footer = MJRefreshAutoNormalFooter(refreshingBlock: { [unowned self] in
let model = self.dataSource[self.dataSource.count - 1]
self.viewModel.fetchRecommendList("answer_feed",model.behot_time)
})
}
func endAllRefresh() {
self.tableView.mj_header.endRefreshing()
self.tableView.mj_footer.endRefreshing()
}
func handleData(_ model: HomeListModel) -> [HomeListDetailModel] {
guard let data = model.detailData else {
return dataSource
}
self.dataSource = data
return data
}
}
2: My ViewModel
protocol HomeProtocol {
func fetchRecommendList(_ category: String, _ behot_time: Int)
}
class HomeViewModel: HomeProtocol {
lazy var provider = HTTPServiceProvider.shared
var recommend: Observable<HomeListModel>!
init() {}
init(_ provider: RxMoyaProvider<MultiTarget>) {
self.provider = provider
}
func fetchRecommendList(_ category: String, _ behot_time: Int) {
recommend = provider.request(MultiTarget(HomeAPI.homeList(category: category,behot_time: behot_time)))
.debug()
.mapObject(HomeListModel.self)
}
}
When I made a breakpoint at request method, it didn't do a request? Does anyone know it ? Thanks first
SomeOne told me the reason,So I write it here. In my ViewModel recommend should be backed by PublishSubject or BehaviourSubject or ReplaySubject and then I should share this for View as Observable. In fetchRecommentList method I should bind request to created Subject.
Now I have created observable, but request will run after subsribe or bind
I'm working on an app, that should request some data from my server. I'm using Alamofire to do that, and then use SWXMLHash to parse the XML data. There are two View Controllers, on the first one I can write a shipment number, then override function prepareForSegue and send that number to the next View Controller that should display data from server and updateUI on viewDidLoad, but it does not. Where is a problem?
My Class:
class Shipment {
private var _shipmentNumber: String!
private var _shipmentStatus: String!
private var _trackURL: String!
var shipmentNumber: String {
if _shipmentNumber == nil {
_shipmentNumber = ""
}
return _shipmentNumber
}
var shipmentStatus: String {
if _shipmentStatus == nil {
_shipmentStatus = ""
}
return _shipmentStatus
}
init(spNumber: String) {
self._shipmentNumber = spNumber
_trackURL = "..."
}
func requestXmlInformation(completed: DownloadComplete) {
let url = NSURL(string: _trackURL)!
Alamofire.request(.GET, url).responseData { response in
if let xmlToParse = response.data as NSData! {
let xml = SWXMLHash.parse(xmlToParse)
do {
let xmlSpWeight = try xml["fmresultset"]["resultset"]["record"]["field"].withAttr("name", "ТotalWeight")["data"].element!.text! as String
self._shipmentStatus = xmlSpStatus
print(self._shipmentStatus)
} catch let err as NSError {
print(err.debugDescription)
}
}
}
}
}
My Second View Controller
#IBOutlet weak var numberLbl: UILabel!
#IBOutlet weak var weightLbl: UILabel!
#IBOutlet weak var statusLbl: UILabel!
#IBOutlet weak var packageQtyLbl: UILabel!
var shipment: Shipment!
override func viewDidLoad() {
super.viewDidLoad()
shipment.requestXmlInformation { () -> () in
self.updateUi()
print(self.statusLbl.text)
}
}
updateUI function:
func updateUi() {
numberLbl.text = shipment.shipmentNumber
weightLbl.text = shipment.shipmentWeight
statusLbl.text = shipment.shipmentStatus
packageQtyLbl.text = shipment.shipmentPackageQty
}
It prints data in terminal but i think updateUI function does not work.
Make sure that the code in your requestXmlInformation closure is called on the main thread. You shouldn't update the UI in background threads.
shipment.requestXmlInformation { () -> () in
dispatch_async(dispatch_get_main_queue(), { () -> Void in
self.updateUi()
print(self.statusLbl.text)
})
}
Also, you don't seem to call the complete closure anywhere in your requestXmlInformation method