RxJava Error Handling

Slides for https://youtu.be/WVyjWf-FlIE

Transcript

1. RxJava Error Quipper Sharing Session 2 - @bopbi
2. When an Error is emitted - The onError callback is called - Stream is closed
3. Why it matters? Usage Example 1. UI subscribe Event emitted from the ViewModel using the Observable 2. ViewModel receive an event/data from UseCase that subscribe to an Repository Event Effect 1. Any Event from the ViewModel will not be received by the UI 2. Any Side Effect event will from Repository will not work as intended
4. Goals ViewModel should maintain the Event/State Stream alive even when error happen UI ViewModel ViewModel Repository Repository
5. OnErrorReturn The input is a function that return a value public final Observable<T> onErrorReturn(Function<? super Throwable, ? extends T> valueSupplier)
6. OnErrorReturnItem The input is the replacement value for the error public final Observable<T> onErrorReturnItem(final T item)
7. OnErrorResumeNext The input is an Observable that will be the replacement value • public final Observable<T> onErrorResumeNext(Function<? super Throwable, ? extends ObservableSource<? extends T>> resumeFunction) • public final Observable<T> onErrorResumeNext(final ObservableSource<? extends T> next)
8. Catch onComplete is called and Stream is ended
9. Demo Code
10. Tips to keep the Stream alive Wrap that Observable inside another Observable/Flowable creation operator and use the error operator properly • Kotlin user: We can use the sealed class to wrap a Event
11. Notes 1. Always expect the Error will emitted 2. Always override the subscriber onError 3. Use the onComplete to detect an Stream is closed, put log inside it source: https://github.com/bopbi/rxerror