RxJava2如何与其他两个观察员共享可观察到的,然后把它合并到用户
问题描述:
我有以下方法RxJava2如何与其他两个观察员共享可观察到的,然后把它合并到用户
Document createDocument(String url);
List<MediaContent> getVideo(Document doc);
List<MediaContent> getImages(Document doc);
名单< MediaContent>将
void appendToRv(List<MediaContent> media);
消耗我喜欢使用RxJava2,使得
CreateDocument -> getVideo ->
-> appendToRv
-> getImages ->
(另外,视频输出应该是有序的b efore图像)。
我该怎么做呢?我试过flatMap,但它似乎只允许使用
Single<List<MediaContent>> single =
Single.fromCallable(() -> createDocument(url))
// . ?? ..
// this is the part i am lost with
// how do i feed document to -> getVideo() and getImage()
// and then merge them back into the subscriber
//
.subscribeOn(Schedulers.io())
.observeOn(AndroidSchedulers.mainThread());
single.subscribe(parseImageSubscription);
的DisposableSingleObserver
parseImageSubscription = new DisposableSingleObserver<List<MediaContent>>() {
@Override
public void onSuccess(List<MediaContent> media) {
if(media!=null) {
appendToRv(media);
}
}
@Override
public void onError(Throwable error) {
doSnackBar("error loading: '" + q + "'");
}
};
单可观的单一方法getVideos和getImages
Single<List<MediaContent>> SingleGetImage(Document document) {
return Single.create(e -> {
List<MediaContent> result = getImage(document);
if (result != null) {
e.onSuccess(result);
}else {
e.onError(new Exception("No images found"));
}
});
}
Single<List<MediaContent>> singleGetVideo(Document document) {
return Single.create(e -> {
List<MediaContent> result = getVideo(document);
if (result != null) {
e.onSuccess(result);
}else {
e.onError(new Exception("No videos found"));
}
});
}
答
假设你想并行执行getVideos
和getImages
请求,您可以使用flatMap()
与zip()
,zip wi我们将收集来自Singles
的2个发射,并且您可以将2个结果合并为一个新值,这意味着您可以对视频MediaContent
列表进行排序,并将其与图像MediaContent
列表结合,并返回统一列表(或其他任何对象) d):
Single<List<MediaContent>> single =
Single.fromCallable(() -> createDocument(url))
.flatMap(document -> Single.zip(singleGetVideo(document), SingleGetImage(document),
(videoMediaContents, imageMediaContents) -> //here you'll have the 2 results
//you can sort combine etc. and return unified object
.subscribeOn(Schedulers.io())
.observeOn(AndroidSchedulers.mainThread());
single.subscribe(parseImageSubscription)
答
Observable.zip()可以实现它的完美。观察者将通过此方法接收合并结果。
public void zip() {
Observable<Integer> observable1 = Observable.just(1);
Observable<Integer> observable2 = Observable.just(2);
Observable.zip(observable1, observable2, new Func2<Integer, Integer, Integer>() {
@Override
public Integer call(Integer integer, Integer integer2) {
return integer + integer2;
}
}).subscribe(new Observer<Integer>() {
@Override
public void onCompleted() {
}
@Override
public void onError(Throwable e) {
}
@Override
public void onNext(Integer o) {
Logger.i(o.toString());
//Here will print 3.
}
});
}