Reputation: 3488
I've two RxJava Observables and I get an arraylist from first observable and then use it to get data from another observable like this.
Observable<KarobarTvVod> observable1 = youtubeDataHelper.getTVData();
observable1.subscribeOn(Schedulers.io())
.observeOn(AndroidSchedulers.mainThread())
.unsubscribeOn(Schedulers.io())
.subscribe(new Subscriber<KarobarTvVod>() {
@Override
public void onCompleted() {
}
@Override
public void onError(Throwable e) {
e.printStackTrace();
}
@Override
public void onNext(KarobarTvVod karobarTvVod) {
Log.d(TAG, "onNext: size" + karobarTvVod.getEtag());
tvObjArrayList = new ArrayList<TVObj>();
for (int i = 0; i < karobarTvVod.getItems().size(); i++) {
TVObj tvObj = new TVObj();
tvObj.setVideoDate(karobarTvVod.getItems().get(i).getSnippet().getPublishedAt());
tvObj.setVideoIcon(karobarTvVod.getItems().get(i).getSnippet().getThumbnails().getHigh().getUrl());
tvObj.setVideoTitle(karobarTvVod.getItems().get(i).getSnippet().getTitle());
tvObj.setVideoID(karobarTvVod.getItems().get(i).getId().getVideoId());
tvObjArrayList.add(tvObj);
}
}
});
Observable<YoutubeViews> observable2 = youtubeDataHelper.getTVDataViews(tvObjArrayList);
observable2.subscribeOn(Schedulers.io())
.observeOn(AndroidSchedulers.mainThread())
.unsubscribeOn(Schedulers.io())
.subscribe(new Subscriber<YoutubeViews>() {
@Override
public void onCompleted() {
}
@Override
public void onError(Throwable e) {
Log.d(TAG, "onError: in 2nd obs");
e.printStackTrace();
}
@Override
public void onNext(YoutubeViews youtubeViews) {
Log.d(TAG, "onNext: views" + youtubeViews.getEtag());
viewsList = new ArrayList<String>();
for (int i = 0; i < youtubeViews.getItems().size(); i++) {
viewsList.add(youtubeViews.getItems().get(i).getStatistics().getViewCount());
}
tvView.displayList(tvObjArrayList, viewsList);
}
});
This is just sample code, I need to pass the tvObjArrayList when it gets populated from 1st Observable to 2nd Observable, what is the best practice to do so ? And also I'm using for-loop inside the 1st Observable, is there a better way to achieve it using rxjava ? Thanks
Upvotes: 10
Views: 5684
Reputation: 4606
I assume that getTVData
and getTVDataViews
each emits one item and than calls onComplete
. If it true, than the following example works. No loop
's, just pure rx
:)
//getTVData should emit one item and then call obComplete
//otherwise toList() will wait forever
service.getTVData()
.flatMap(karobarTvVod -> Observable.from(karobarTvVod.getItems()))
.map(item -> {
TVObj tvObj = new TVObj();
//set other fields
//by the way, I recommend you to use immutable objects
return tvObj;
})
.toList()
//here we have List<TVObj>
.flatMap(
objs -> {
//getTVDataViews should emit one item and then call onComplete
//otherwise toList will wait forever
return service.getTVDataViews(objs)
.flatMap(youtubeViews -> Observable.from(youtubeViews.getItems()))
.map(integer -> integer.toString())
//after that we will have List<String>
.toList();
},
//a function that combines one item emitted by each of the source and collection Observables
// and returns an item to be emitted by the resulting Observable
new Func2<List<TVObj>,List<String>,Pair<List<TVObj>,List<String>>>() {
@Override
public Pair<List<TVObj>, List<String>> call(List<TVObj> objs, List<String> strings) {
return new Pair(objs, strings);
}
})
.subscribe(pair -> tvView.displayList(pair.first, pair.second));
PS. While this approach is more concise, I believe that loop
for creating list
of items is more efficient.
Upvotes: 1
Reputation: 537
You can use operator
toList().flatMap()
for Observable A, and in flatMap function, do work for Observable B.
For example:
observableA
.toList()
.flatMap(observableB.subscribe())
.subscribe()
Upvotes: 1
Reputation: 31468
You should use flatMap
operator. It won't get much easier than that.
Observable<KarobarTvVod> observable1 = youtubeDataHelper.getTVData();
observable1.subscribeOn(Schedulers.io())
.observeOn(AndroidSchedulers.mainThread())
.unsubscribeOn(Schedulers.io())
.flatMap(new Func1<KarobarTvVod, Observable<YoutubeViews>>() {
@Override
public Observable<YoutubeViews> call(KarobarTvVod karobarTvVod) {
Log.d(TAG, "onNext: size" + karobarTvVod.getEtag());
tvObjArrayList = new ArrayList<TVObj>();
for (int i = 0; i < karobarTvVod.getItems().size(); i++) {
TVObj tvObj = new TVObj();
tvObj.setVideoDate(karobarTvVod.getItems().get(i).getSnippet().getPublishedAt());
tvObj.setVideoIcon(karobarTvVod.getItems().get(i).getSnippet().getThumbnails().getHigh().getUrl());
tvObj.setVideoTitle(karobarTvVod.getItems().get(i).getSnippet().getTitle());
tvObj.setVideoID(karobarTvVod.getItems().get(i).getId().getVideoId());
tvObjArrayList.add(tvObj);
}
return youtubeDataHelper.getTVDataViews(tvObjArrayList);
}
}).subscribe(new Subscriber<YoutubeViews>() {
@Override
public void onCompleted() {
}
@Override
public void onError(Throwable e) {
Log.d(TAG, "onError: in 1st or 2nd obs");
e.printStackTrace();
}
@Override
public void onNext(YoutubeViews youtubeViews) {
Log.d(TAG, "onNext: views" + youtubeViews.getEtag());
viewsList = new ArrayList<String>();
for (int i = 0; i < youtubeViews.getItems().size(); i++) {
viewsList.add(youtubeViews.getItems().get(i).getStatistics().getViewCount());
}
tvView.displayList(tvObjArrayList, viewsList);
}
});
Upvotes: 5
Reputation: 13481
You need to subscribe the second observable in the onComplete of the first one
Observable<KarobarTvVod> observable1 = youtubeDataHelper.getTVData();
Observable<YoutubeViews> observable2 = youtubeDataHelper.getTVDataViews(tvObjArrayList);
observable1.subscribeOn(Schedulers.io())
.observeOn(AndroidSchedulers.mainThread())
.unsubscribeOn(Schedulers.io())
.subscribe(new Subscriber<KarobarTvVod>() {
@Override
public void onCompleted() {
observable2.subscribeOn(Schedulers.io())
.observeOn(AndroidSchedulers.mainThread())
.unsubscribeOn(Schedulers.io())
.subscribe(new Subscriber<YoutubeViews>() {
@Override
public void onCompleted() {
}
@Override
public void onError(Throwable e) {
Log.d(TAG, "onError: in 2nd obs");
e.printStackTrace();
}
@Override
public void onNext(YoutubeViews youtubeViews) {
Log.d(TAG, "onNext: views" + youtubeViews.getEtag());
viewsList = new ArrayList<String>();
for (int i = 0; i < youtubeViews.getItems().size(); i++) {
viewsList.add(youtubeViews.getItems().get(i).getStatistics().getViewCount ());
}
tvView.displayList(tvObjArrayList, viewsList);
}
});
}
@Override
public void onError(Throwable e) {
e.printStackTrace();
}
@Override
public void onNext(KarobarTvVod karobarTvVod) {
Log.d(TAG, "onNext: size" + karobarTvVod.getEtag());
tvObjArrayList = new ArrayList<TVObj>();
for (int i = 0; i < karobarTvVod.getItems().size(); i++) {
TVObj tvObj = new TVObj();
tvObj.setVideoDate(karobarTvVod.getItems().get(i).getSnippet().getPublishedAt());
tvObj.setVideoIcon(karobarTvVod.getItems().get(i).getSnippet().getThumbnails().getHigh().getUrl());
tvObj.setVideoTitle(karobarTvVod.getItems().get(i).getSnippet().getTitle());
tvObj.setVideoID(karobarTvVod.getItems().get(i).getId().getVideoId());
tvObjArrayList.add(tvObj);
}
}
});
Of course to make this code more readable I would use a Consumer function for the observable2.subsriberOn on the onComplete method
Upvotes: 0