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使用 kotlin，有代码

fun fetchRemoteDataApi(): Single<RemoteDataResponse> = networkApi.getData()

    // it is just a retrofit
    @GET(".../api/getData")
    fun getData() : Single<RemoteDataResponse>

fun mergeApiWithDb(): Completable = fetchRemoteDataApi()
            .zipWith(localDao.getAll())
            .flatMapCompletable { (remoteData, localData) ->
                doMerge(remoteData, localData) //<== return a Completable
            }

代码流程：

    val mergeApiDbCall = mergeApiWithDb().onErrorComplete().cache() //<=== would like do some inspection at this level
    PublishSubject.create<Unit>().toFlowable(BackpressureStrategy.LATEST)
                .compose(Transformers.flowableIO())
                .switchMap {
                    //merge DB with api, or local default value first then listen to DB change
                    mergeApiDbCall.andThen(listAllTopics())
                            .concatMapSingle { topics -> remoteTopicUsers.map { topics to it } }
                }
                .flatMapCompletable { (topics, user) ->
                    // do something return Completable
                }
                .subscribe({
                    ...
                }, { throwable ->
                    ...
                })

以及打电话的时候

val mergeApiDbCall = mergeApiWithDb().onErrorComplete().cache()

问题是是否要检查Singles<RemoteDataResponse>返回的fetchRemoteDataApi()（即使用 Log.i(...) 打印输出的内容RemoteDataResponse等），无论是在出错还是成功的情况下，怎么做？

/// the functions
fun listAllTopics(): Flowable<List<String>> = localRepoDao.getAllTopics()

// which a DAO:
    @Query("SELECT topic FROM RemoteDataTable WHERE read = 1")
    fun getAllTopics(): Flowable<List<String>>

///
private val remoteTopicUsers: Single<List<User>>
        get() {
            return Single.create {
                networkApi.getTopicUsers(object : ICallback.IGetTopicUsersCallback {
                    override fun onSuccess(result: List<User>) = it.onSuccess(result)
                    override fun onError(errorCode: Int, errorMsg: String?) = it.onError(Exception(errorCode, errorMsg))
                })
            }
        }
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1 回答 1

1

您不能从Completable. 尽管您可以使用doOnComplete()on Completable，但它不会为您提供有关该元素的任何信息。

如果您调用doOnSuccess()，您可以检查元素Single，因此您需要在代码中更早地合并此调用。要检查错误，您可以doOnError()同时使用Completable或Single。

于 2021-02-19T21:48:05.723 回答