ios - RxSwift的奇怪行为结合了多个可观察对象

我对反应式编程非常陌生，因此我仍然很难理解它的工作原理。
我正在尝试做的事情:，当用户点击signUpButton(signUpTrigger)时，会触发多个可观察对象。我正在结合他们的结果并产生新的Observable(signUp)。
会发生什么:当用户点击signUpButton(signUpTrigger)时，我从putProfileImage和createUser observables获取数据，但从signUp observable中获取数据。我认为可以编写逻辑使其起作用，但我自己努力尝试。

020-08-31 22:28:36.457: signUp -> subscribed
2020-08-31 22:28:36.458: createUser -> subscribed
2020-08-31 22:28:36.459: createProfileImage -> subscribed
2020-08-31 22:28:48.843: createUser -> Event next(<FIRAuthDataResult: 0x6000036fd860>)
2020-08-31 22:28:48.988: createProfileImage -> Event next(https://firebasestorage.googleapis.com/v0/b/primeval-gear-236918.appspot.com/o/profile_images%2F8173E542-93DD-4594-BAA8-705A17227F1B?alt=media&token=85c68612-bea4-41a5-a680-88a61c2e8989)

下面的所有Viewmodel和VC代码:

final class SignUpViewModel: ViewModelType {

    func transform(input: Input) -> Output {

        let auth = Auth.auth()
        let filename = NSUUID().uuidString


        let storageRef = Storage
            .storage()
            .reference()
            .child("profile_images")
            .child(filename)
            .rx

        let databaseRef = Database
            .database()
            .reference()
            .child("users")
            .rx

        let putProfileImage = input.signUpTrigger
            .withLatestFrom(input.profileImage)
            .flatMap { data in
                storageRef.putData(data)
            }.flatMap { _ in
            storageRef.downloadURL()
        }.debug("createProfileImage")

        let createUser = input.signUpTrigger
            .withLatestFrom(Observable.combineLatest(input.email, input.password))
            .flatMap { (email,password) in
                auth.rx.createUser(withEmail: email, password: password)
        }.debug("createUser")

        let signUp = input.signUpTrigger
            .withLatestFrom(Observable.combineLatest(createUser, putProfileImage, input.username))
            .flatMap { createUserResult, url, username -> Observable<DatabaseReference> in
                let profileImageUrl = url.absoluteString
                let uid = createUserResult.user.uid
                let dictionary = ["username": username, "profileImageUrl": profileImageUrl]
                let values = [uid: dictionary]
                return databaseRef.updateChildValues(values)
                    .asObservable()
        }.debug("signUp")


        let canSignUp = Observable.combineLatest(input.username, input.password, input.email)
        { username, password, email in
            return !username.isEmpty && !password.isEmpty && !email.isEmpty
        }

        return Output(canSignUp: canSignUp, isLoading: isLoading, signUp: signUp)
    }

}

class SignUpViewController : UIViewController {

    var disposeBag = DisposeBag()

    @Injected var signUpView : SignUpView
    @Injected var viewModel : SignUpViewModel

    lazy var plusPhotoButton = signUpView.plusPhotoButton
    lazy var signUpButton = signUpView.signUpButton
    lazy var emailTextField = signUpView.emailTextField
    lazy var usernameTextField = signUpView.usernameTextField
    lazy var passwordTextField = signUpView.passwordTextField

    override func loadView() {
        view = signUpView
    }

    override func viewDidLoad() {
        super.viewDidLoad()
        setupBindings()
    }

    func setupBindings() {

        let input = SignUpViewModel.Input(
            username: usernameTextField.rx.text.orEmpty.asObservable(),
            password: passwordTextField.rx.text.orEmpty.asObservable(),
            email: emailTextField.rx.text.orEmpty.asObservable(),
            signUpTrigger: signUpButton.rx.tap.asObservable(),
        )

        let output = viewModel.transform(input: input)

        output.canSignUp
            .bind(to:signUpButton.rx.signUpEnabled)
            .disposed(by: disposeBag)

        output.signUp
            .bind(onNext: { result in
                print(result)
            }).disposed(by:disposeBag)


    }
}

最佳答案

您现在拥有代码的方式:

let signUp = input.signUpTrigger
    .withLatestFrom(Observable.combineLatest(createUser, putProfileImage, input.username))

signtTrigger触发后，updateChildValues(_:)将立即发生，但是您不希望这样。您希望一旦其他三个事件的结果发生，它就会发生。
所以你想要这样的东西:

let signUp = Observable.zip(createUser, putProfileImage, input.signUpTrigger.withLatestFrom(input.username))
    .flatMap { createUserResult, url, username -> Observable<DatabaseReference> in
        let profileImageUrl = url.absoluteString
        let uid = createUserResult.user.uid
        let dictionary = ["username": username, "profileImageUrl": profileImageUrl]
        let values = [uid: dictionary]
        return databaseRef.updateChildValues(values)
            .asObservable()
        }
        .debug("signUp")

关于ios - RxSwift的奇怪行为结合了多个可观察对象，我们在Stack Overflow上找到一个类似的问题：https://stackoverflow.com/questions/63677105/