CODEWITHSUNDEEP
androidrx-javarx-java2
hawarden_
hawarden_

Reputation: 2160

RxJava : retrieve data from database and return a list

I use RxJava in my Android project, I want to retrieve all entities User from a table using RxJava asynchronously and return the list List to an adapter myAdapter(Context context, List<User> users).

But now I can only have Single<User>, how can I get the list directly and put it into my adapter ?

My code:

// here vm.getUserList() should return a List<User>
MyAdapter adapter = new MyAdapter(context, vm.getUserList());
...

And in my vm:

public Single<List<User>> getUserList() {
    return Single.fromCallable(() -> myDatabaseRepository.getUsers());
}

Upvotes: 1

Views: 744

Answers (2)

Jaime Suarez
Jaime Suarez

Reputation: 660

You only need to call the users method and handle the success/error in the corresponding method.

getUserList()
   .subscribeOn(Schedulers.io())
   .observeOn(AndroidSchedulers.mainThread())
   .doOnSuccess(new Consumer<List<User>>() {
      @Override
      public void accept(List<User> users) throws Exception {
         // fill adapter
         MyAdapter adapter = new MyAdapter(context, users);
      }
   })
   .doOnError(new Consumer<Throwable>() {
      @Override
      public void accept(Throwable throwable) throws Exception {
         // handle error
      }
   });

Yes, this is the normal way of retrieving the data from the database/network. You expose from the repository the Observables/Singles, then you subscribe to them and receive the data in the success/error methods to show in the UI to the user.

Upvotes: 1

Antonio
Antonio

Reputation: 1274

private void fetchUser() {
            ('function returning Single<List<User>>').subscribeOn(Schedulers.io())
            .observeOn(AndroidSchedulers.mainThread())
            .subscribe(this::onSuccess, this::onFail);
}

private void onSuccess(List<User> users) {
    //handle user model here
}

private void onFail(Throwable t) {
    //handle error here
}

Upvotes: 0

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