如何将rxJava2的Observable转换为Completable？

Question

我有Observable流，我想将它转换为Completable，我怎么能这样做？

Answer 1

The fluent way is to use Observable.ignoreElements() .

Observable.just(1, 2, 3)
.ignoreElements()

Convert it back via toObservable if needed.

Answer 2

You can do something like below.

Observable<Integer> observable = Observable.just(1, 2, 3);
Completable completable = Completable.fromObservable(observable);

Like on an Observable, you will have to subscribe to the completable to start the asynchronous process that Observable wraps.

More details can be found here in the Java doc for the method .

Answer 3

As I understand all this solutions will work only if Observable call onComplete , which is not enough if you want your result Completable to trigger after first onNext or onError , so for this case I'd recommend this:

Observable<Integer> observable = Observable.just(1, 2, 3);
Completable completable = observable.firstOrError().ignoreElement()

Answer 4

使用Completable.merge（YourObservable（）......

Answer 5

You could use Completable.fromObservable(xx) . That is worked fine on my project.