CODEWITHSUNDEEP
kotlinobservablerx-javarx-java2
matip
matip

Reputation: 890

RxJava Observable on error fetch items from database but still pass error through

In my application I am getching data from api and if there is an error while doing that I would like to get data from database but also show error message on the screen. So how I thought about doing this is use something like onErrorResumeNext. I can get data from database using this but the problem is that onError is not called then and I can't show error message to user. So my code is:

override fun getData(): Observable<List<MyData>> {
    return getDataFromApi().onErrorResumeNext(getDataFromDatabase())
}

How can I somehow fetch database on error and simultaneously know that error message needs to be displayed?

Upvotes: 1

Views: 160

Answers (1)

David Rawson
David Rawson

Reputation: 21407

You could change the way you model the domain to something like the following:

sealed class Result {
    class Simple(data: List<MyData>) : Result()

    class HasError(data: List<MyData>, throwable: Throwable) : Result()
}

Then you can do:

fun getResult(): Observable<Result> {
    return getDataFromApi().map<Result> { Result.Simple(it) }
        .onErrorResumeNext { throwable ->
            getDataFromDatabase().map { myDataList ->
                Result.HasError(
                    myDataList,
                    throwable
                )
            }
        }
}

Upvotes: 1

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