Android RxJava 2, subscribeOn 和 BehaviorSubject 留在 MainThread

Question

我在 Android 中使用带有 RxJava2 的 BehaviourSubject。在以下链中，即使我订阅了（schedulers.background（）），我也会收到 NetworkOnMainThreadException。

如果我在 searchRequestSubject 之后使用 ObserveOn(schedulers.background())，我会正确地进入后台线程。

我希望使用 subscribeOn 将所有链条放入提供的线程中？为什么它不是这样工作的？

private BehaviorSubject<SearchRequest> searchRequestSubject = BehaviorSubject.create();

searchRequestSubject
            .doOnEach(responseNotification -> Logger.d("Current Thread1: "+Thread.currentThread()))
//.observeOn(schedulers.background()) // this is the current solution but
            .flatMap(searchRequest -> adSearchService.getAds(searchRequest))
            .doOnEach(responseNotification -> Logger.d("Current Thread2: "+Thread.currentThread()))
            .doOnNext(apiResponse -> updateResponseSubject(apiResponse))
            .doOnEach(responseNotification -> Logger.d("Current Thread3: "+Thread.currentThread()))
            .subscribeOn(schedulers.background()) // this one should make the whole chain to subscribe on background. but it don't. why?
            .subscribe()

// Logs //
Current Thread1: Thread[main,5,main]
Current Thread2: Thread[main,5,main]
Current Thread3: Thread[main,5,main]

网络调用

public Observable<ApiResponse> getAds(@NonNull SearchRequest adRequest){
    if (adRequest == null){
        throw new IllegalStateException("Search Request should never be null");
    }

    return apiService.getAdsObservable(token, adRequest.pageNumber(), adRequest.resultsNumberByPage(), adRequest.presentation(),
            adRequest.toLatLongQuery(), adRequest.isClosed(), adRequest.toAdTypeQuery(), adRequest.category(),
            adRequest.keywords(),adRequest.radius(), adRequest.from(), adRequest.to(), adRequest.isReserved(), adRequest.adId())
        .map(response -> handleResponseCode(response, adRequest.location()))
        .onErrorReturn(error -> errorHandling.handleError(error));
}

private ApiResponse handleResponseCode(Response<AdResponse> response, Location location) {
    if (response.isSuccessful()){
        return AdSearchResponse.Response.create(response.body(), location);
    } else if (response.code() == 404){
        return AdSearchResponse.NotFoundError.create();
    } else {
        return errorHandling.handleError(response, null);
    }
}

ApiService由Retrofit 2提供

@AutoValue
public abstract class AppSchedulers {
    public abstract Scheduler UI(); // AndroidSchedulers.mainThread()
    public abstract Scheduler background(); // Schedulers.io()
    // [...] creator and builder
}

Answer 1

实际上这是因为您使用的是热可观察对象 (BehaviorSubject)，除非您使用的是 observeOn，否则您将停留在执行 onNext 的线程上。 subscribeOn 大部分时间用于冷可观察对象。所以在你的情况下：

searchRequestSubject
    .observeOn(schedulers.background())
    .doOnEach(responseNotification -> Logger.d("Current Thread1: "+Thread.currentThread()))
    .flatMap(searchRequest -> adSearchService.getAds(searchRequest))
    .doOnEach(responseNotification -> Logger.d("Current Thread2: "+Thread.currentThread()))
    .doOnNext(apiResponse -> updateResponseSubject(apiResponse))
    .doOnEach(responseNotification -> Logger.d("Current Thread3: "+Thread.currentThread()))
    .subscribe()

检查 link，转到 ObserveOn 部分：http://tomstechnicalblog.blogspot.ca/2016/02/rxjava-understanding-observeon-and.html 你的onNext就像一个点击动作

Answer 2

在愤怒、沮丧和单元测试之后表明这不是由于可观察到的热/冷问题。我已经清理了构建。重新启动 Android Studio。再次构建，它按预期工作，没有任何更改。

总是Clean/Rebuild有任何疑问...

Android RxJava 2, subscribeOn 和 BehaviorSubject 留在 MainThread

Android RxJava 2, subscribeOn with BehaviorSubject stay on MainThread

android

rx-java2