Rxswift的异常行为结合了多个可观察对象

问题描述

我对反应式编程非常陌生，所以我仍然很难理解它的工作原理。

我要做什么：：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可观察对象中获取数据，但从signUp可观察对象中获取任何数据。我认为可以编写逻辑使之起作用，但是我自己想尽办法。

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)
     
        
    }
}

解决方法

您现在拥有代码的方式：

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

updateChildValues(_:)将在signUpTrigger触发后立即发生，但是您不希望这样。您希望它在其他三个事件的结果发生后发生。

所以你想要这样的东西：

let signUp = Observable.zip(createUser,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")