CODEWITHSUNDEEP
androidretrofitrx-java2
GyPT
GyPT

Reputation: 11

How to wait/observe incoming data from server correctly with rxjava/retrofit

I have a problem with downloading data from server, to be more specific I cannot implement a "waiting/observing incoming data" behavior. I want to fill up my RecyclerView and Spinner with lists come from server, but right know, the methods return null/empty list. I understand, the problem is that the method finish before the data arrives.

I've checked these two questions which are similar, but none of the answers worked for me:

Waiting for API Calls to complete with RxJava and Retrofit

RXJava retrofit waiting having the UI wait for data to be fetched from API

My code:

API:

@GET("/api/categories")
Observable<Response<JsonObject>> getCategories();

netWorker:

public List<String> getCat() {
    List<String> incomingDataSet = new ArrayList<>();
    
    compositeDisposable.add(
        apiConnector.getCategories()
            .subscribeOn(Schedulers.io())
            .observeOn(AndroidSchedulers.mainThread())
            .subscribe(response -> {
                if (response.code() >= 200 && response.code() < 300) {
                    JsonArray incomingArray = response.body().getAsJsonArray("category");
                    
                    for (int i = 0; i < incomingArray.size(); i++) {
                        incomingDataSet.add(incomingArray.get(i).getAsJsonObject().get("categoryname").toString().replaceAll("\"", ""));
                        Log.i("LOG", "downloadCategories response: " + incomingDataSet.toString());
                    }

                } else {
                    Log.i("LOG", "Response error: " + response.code());
                }
            })
    );

    Log.i("LOG", "getCat: " + incomingDataSet.toString());
    
    return incomingDataSet;
}

MainActivity:

List<String> categorylist = new ArrayList<>();
categorylist = netWorker.getCat();
Log.i("LOG", "list:" + categorylist );

So, what I see in log:

First:

getCat: []

list: []

and then:

downloadCategories response: [cat1]

downloadCategories response: [cat1, cat2]

downloadCategories response: [cat1, cat2, cat3]

Upvotes: 1

Views: 327

Answers (1)

Maxim Alov
Maxim Alov

Reputation: 664

Show spinner in doOnSubscribe() and hide in doFinally(). Put code that fills RecyclerView inside subscribe() to fill it when data arrives. Otherwise you just get empty new list on Main thread and do not update RecyclerView further.

Upvotes: 1

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