How to merge with Observable inside loop?

Question

I would like to merge several Obserables into one. I use Observable.mergeWith() method. My requirement is to merge inside the loop. The problem is no emissions are sent on subscription. The issue seems to be way I initialize main Observale using Observable<String> observable = Observable.never(); but I did not find the proper way to do it (tried PublishSubject.create(); and Observable.empty();)

import io.reactivex.Observable;
import io.reactivex.rxjavafx.observables.JavaFxObservable;
import javafx.application.Application;
import javafx.scene.Scene;
import javafx.scene.control.Button;
import javafx.scene.layout.VBox;
import javafx.stage.Stage;

public class NeverApplication extends Application {

    public static void main(String[] args) {
        launch(args);
    }

    @Override
    public void start(Stage stage) throws Exception {

        Observable<String> observable = Observable.never();

        VBox vBox = new VBox();

        for (int i = 0; i < 4; i++) {
            Button button = new Button("Button " + i);
            vBox.getChildren().add(button);
            Observable<String> clickedObservale = JavaFxObservable.actionEventsOf(button).map(event -> button.getText());
            observable.mergeWith(clickedObservale);
        }

        stage.setScene(new Scene(vBox));
        stage.show();

        observable.subscribe(next -> System.out.println(next));
    }
}

You probably want `observable = observable.mergeWith(clickedObservale)`. I'm not a Java programmer, but I assume it's functional like in C#. — Enigmativity, Feb 12 '19 at 10:28

score 1 · Answer 1 · answered Feb 12 '19 at 10:32

Gather them as Iterable preferebly a simple List, and use static method Observable.merge

List<Observable<String>> observables = new ArrayList<>();
observables.add(Observable.never());
for (int i = 0; i < 4; i++) {
    observables.add(...);
}

Observable.merge(observables).subscribe();

How to merge with Observable inside loop?

1 Answers1