ios - RxSwift 代码第一次运行，第二次部分运行

Question

我正在学习 RxSwift，我遇到了登录逻辑问题。

我的代码运行正常吗？一次，部分是第二次，注销后。

这是我的 View 模型:

func transform(input: Input) -> Output {
    let user = fetchUser(loginAction: input.loginAction, domain: input.domain,
                           username: input.username, password: input.password)

    return Output(user: user, error: errorTracker.asDriver())
}

func fetchUser(loginAction: Driver<Void>, domain: Driver<String>, email: Driver<String>, password: Driver<String>)->Driver<User>{
    let credentials = Driver.combineLatest(domain, email, password) {
        $0
    }


    return loginAction.withLatestFrom(credentials)
        .flatMapLatest { [unowned self]  (domain, username, password) in
            return self.useCase.login(params: ["domain": domain, "username": username, "password": password])
                .trackActivity(self.activityIndicator)
                .trackError(self.errorTracker)
                .asDriverOnErrorJustComplete()
                .map { [unowned self] in
                    if let token = $0.token {
                        return self.decodeUserId(token: token)
                    }
                    return ""
                }
                .flatMapLatest { [unowned self] userId in
                    return self.useCase.getUser(params: ["userId": userId])
                        .trackActivity(self.activityIndicator)
                        .trackError(self.errorTracker)
                        .asDriverOnErrorJustComplete()
            }
    }
}
    struct Input {
    let loginAction: Driver<Void>
    let tenant: Driver<String>
    let email: Driver<String>
    let password: Driver<String>
}

struct Output {
    let user: Driver<User>
    let error: Driver<Error>
}

它第一次工作，登录检索包含 token 字符串的对象，在 map 部分对其进行解码以获取用户 ID，然后 getUser 通过 ID 获取用户。

在 View Controller 中我有这个绑定(bind)方法:

func bindViewModel() {
    let domainChange = domainField.rx.text.orEmpty.asDriver()
    let usernameChange = usernameField.rx.text.orEmpty.asDriver()
    let passwordChange = passwordField.rx.text.orEmpty.asDriver()
    let input = LoginViewModel.Input(loginAction: loginButton.rx.tap.asDriver(),
                                     domain: domainChange,
                                     username: usernameChange,
                                     password: passwordChange)

    let output = viewModel.transform(input: input)
    output.user.drive(successBinding).addDisposableTo(disposeBag)
    output.error.drive(errorBinding).addDisposableTo(disposeBag)
}

successBinding 和 errorBinding 都是 UIBindingObservers，我认为它们不是这里的问题。 注销后(返回登录，弹出)当我尝试点击登录按钮时，只有第一部分运行，登录方法并成功检索 token ，但它不会进入映射逻辑或用户获取逻辑。 任何帮助将不胜感激。

Answer 1

我认为罪魁祸首在这里:

.asDriverOnErrorJustComplete()
.map { [unowned self] in
    if let token = $0.token {
        return self.decodeUserId(token: token)
    }
    return ""
}

如果登录错误或完成但未发出 next 元素，则映射中的 token 处理将不会执行任何操作，并且不会在该 flatMap 链中向下传递任何内容>.

至于清理你的代码......我宁愿看到这样的东西:

func fetchUser(loginAction: Driver<Void>, domain: Driver<String>, email: Driver<String>, password: Driver<String>)->Driver<User>{
    let credentials = Driver.combineLatest(domain, email, password)
    let latestCredentials = loginAction.withLatestFrom(credentials)
    let loginResult = latestCredentials.flatMapLatest { [unowned self] domain, username, password in
        self.useCase.login(params: ["domain": domain, "username": username, "password": password])
            .trackActivity(self.activityIndicator)
            .trackError(self.errorTracker)                
            .asDriverOnErrorJustComplete()
    }
    let token = loginResult.map { result in
        guard let token = result.token else { return "" }
        return token
    }
    let userID = token.map { [unowned self] in self.decodeUserId(token: $0) }
    return userID.flatMapLatest { userID in
        return self.useCase.getUser(params: ["userId": userId])
            .trackActivity(self.activityIndicator)
            .trackError(self.errorTracker)
            .asDriverOnErrorJustComplete()
    }
}