java - 如何让flatMap在后台线程执行

Question

我正在使用 Retrofit 和 RxJava 来执行一些后台任务。代码如下所示:

public class MyLoader{  
  public Observable<MyData> getMyData(){
      return setupHelper().flatMap(new Func1<MyHelper, Observable<MyData>>() {
              @Override
              public Observable<MyData> call(MyHelper myHelper) {
                  return queryData(myHelper);
              }
      });
  }

  private Observable<MyData> queryData(MyHelper myHelper){
      ...
  }

  private Observable<MyHelper> setupHelper(){
     return Observable.create(new Observable.OnSubscribe<MyHelper>() {
          @Override
          public void call(final Subscriber<? super MyHelper> subscriber) {
              try{
                MyHelper helper = makeRetrofitCall();//Using Retrofit blocking call to get some data
                subscriber.onNext(helper);
                subscriber.onCompleted();
              }catch(RetrofitError e){
                subscriber.onError(e)
              }
          }
     }
  }
}

由于 NetworkOnMainThread 此行出现异常，导致 RetrofitError 失败:

  MyHelper helper = makeRetrofitCall();//Using Retrofit blocking call to get some data

订阅我的 Observable:

myLoader.getMyData()
                .subscribeOn(Schedulers.io())
                .observeOn(AndroidSchedulers.mainThread())
                .subscribe(new Subscriber<MyData>() {
                    @Override
                    public void onCompleted() {

                    }

                    @Override
                    public void onError(Throwable e) {

                    }

                    @Override
                    public void onNext(MyData inventory) {

                    }
                });

根据 Rx 文档 flatMap 不在任何后台线程上运行。我的问题是如何确保整个 getMyData() 方法在后台运行。

Answer 1

我只需在 flatMap 之前添加 observeOn(Schedulers.newThread()) 就可以了!