[英]Rxswift strange behaviour combining multiple observables
I'm quite new to reactive programming so it's still hard to me to comprehend how it works.我对反应式编程还很陌生,所以我仍然很难理解它是如何工作的。
What I'm trying to do: when user taps on signUpButton (signUpTrigger), multiple observables are fired.我想做的是:当用户点击 signUpButton (signUpTrigger) 时,会触发多个可观察对象。 I'm combining their results and producing new observable (signUp).
我正在结合他们的结果并生成新的可观察对象 (signUp)。
What happens : when user taps on signUpButton (signUpTrigger), I'm getting data from putProfileImage and createUser observables, but nothing from signUp observable.发生了什么:当用户点击 signUpButton (signUpTrigger) 时,我从 putProfileImage 和 createUser observables 获取数据,但没有从 signUp observable 获取数据。 I assume it's possible to write logic to make it work, but I'm struggling to come up with it myself.
我认为可以编写逻辑来使其工作,但我正在努力自己想出它。
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)
All the Viewmodel and VC code below:以下所有 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)
}
}
The way you have your code right now:您现在拥有代码的方式:
let signUp = input.signUpTrigger
.withLatestFrom(Observable.combineLatest(createUser, putProfileImage, input.username))
The updateChildValues(_:)
will happen immediately after the signUpTrigger fires, but you don't want that. updateChildValues(_:)
将在 signUpTrigger 触发后立即发生,但您不希望这样。 You want it to happen once the results of the other three events occur.您希望它在其他三个事件的结果发生时发生。
So you want something like this: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")
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