Flatmap Single into Observable and ignore errors

I have UI observable which should work as long as my UI lives. When my UI emits I create a network request which could be an Observable or a Single. A Single fits best for a network call.

RxView.clicks(myButton)
    .flatMap(v - > networkRequest())
    .subscribe(data -> showSomething(data),
            e -> {
                // should only be called when the RxView.clicks() throws. 
                // should not be called for network errors
            });

When using an Observable I would use onErrorResumeNext returning Observable.empty() to prevent errors coming from the network request going into my UI Observable and calling onError because the UI Observable should life forever:

Observable networkRequest() {
    mApiService.fireActionObservable()
        .onErrorResumeNext(throwable -> {
            // somehow handle error here
            return Observable.empty();
     });
}

This, in my opinion, elegant way does not work for Single because no Single.empty() exists.

Single networkRequest() {
    mApiService.fireActionSingle()
        .onErrorResumeNext(throwable -> {
            // somehow handle error here
            return Single.empty(); // <-- does not exist. I have to call success or error :/
     });
}

Single.onErrorResumeNext is btw only available in 2.x

Converting my Single to an Observable seems wrong, because the network request is a Single!

[akarnokd]

Single.empty() doesn’t make sense because Single has to emit either an onSuccess or an onError. The best you can do is to have a Single.just() with a normal value that represents emptiness.

Generally, this is why I’m skeptic about Single and Completable because Observable can “emulate” both and the overhead in true async use is negligible.

[ShabanKamell]

My solution: RxView.clicks(myButton) .flatMap(v - > networkRequest()) .compose(exceptionHandling()) .subscribe(data -> showSomething(data), e -> { // Now you should remove this lambda as it will never be called. }); Final: RxView.clicks(myButton) .flatMap(v - > networkRequest()) .compose(exceptionHandling()) .subscribe(data -> showSomething(data)); exceptionHandling: protected <T> ObservableTransformer<T, T> exceptionHandling() { return observable -> observable .doOnError(t ->{ /* handle error here */}) .retry(); // Ignore error to keep subscription. }