RxSwift trigger observable on button tap - rx-swift

Question

I am creating a custom observable that will present a UIAlertController which would like to trigger an API Call when pressed. However, I can't seem to get the Alert to pop unless I manually subscribe to it. Is there a way to get this triggered from the viewModel?
MyController.swift
class MyController: UIViewController {
#IBOutlet weak var nextBarButton: UIBarButtonItem!
var viewModel: ViewModel!
override func viewDidLoad() {
super.viewDidLoad()
viewModel = ViewModel( nextBarButton.rx.tap.asDriver(), alertController()asDriver(onErrorJustReturn: ""))
}
func alertController() -> Observable<String> {
return Observable.create { [weak alert = self] observer in
guard let alert = alert else {
observer.on(.completed)
return Disposables.create()
}
let alertVc = UIAlertController(title: "My Title", message: "My Message", preferredStyle: .alert)
let submit = UIAlertAction(title: "Continue", style: .default) { _ in
observer.onNext("Test")
observer.on(.completed)
}
let cancel = UIAlertAction(title: "Cancel", style: .cancel) { _ in
observer.on(.completed)
}
alertVc.addAction(cancel)
alertVc.addAction(submit)
alert.present(alertVc, animated: true, completion: nil)
return Disposables.create {
alertVc.dismiss(animated: true, completion: nil)
}
}
}
}
ViewModel.swift
public final class ViewModel {
init(_ manager: SessionManager, _ trigger: Driver<Void>, _ alert: Driver<String>) {
let _ = trigger.withLatestFrom(alert)
.flatMap { text in
return manager.rx
.request(urlRequest: Api.test)
.retry(3)
.asDriverOnErrorJustComplete()
}
}
}

Answer 1

You forgot to subscribe() in your ViewModel and you should flatMapLatest when chaining events from UIButton. It should look like:
public final class ViewModel {
init(_ manager: SessionManager, _ trigger: Driver<Void>, _ alert: Driver<String>) {
let _ = trigger.flatMapLatest{ alert }
.flatMap { text in
return manager.rx
.request(urlRequest: Api.test)
.retry(3)
.asDriverOnErrorJustComplete()
}
.subscribe()
}
}