RxJava UndeliverableException 如何处理onSuccess 消费异常？

Question

该异常最终未得到处理，并在 Crashlytics 中被报告为非致命异常，因此不在我们的关注范围内用户看到了一个不希望出现的空白屏幕崩溃会更好，因为 fail-fast 是首选

理想情况下，我希望 onError 消费者被触发，这就是我处理错误的地方，例如每个流

显示错误 UI

然而，

fun main() {
    Single.just(listOf("efaewf"))
            .subscribe({
                println("result is ${it[1]}")
            }, {
                println("handling exception")
                it.printStackTrace()
            })
}

表明 onError 消费者没有工作

io.reactivex.exceptions.UndeliverableException: The exception could not be delivered to the consumer because it has already canceled/disposed the flow or the exception has nowhere to go to begin with. Further reading: https://github.com/ReactiveX/RxJava/wiki/What's-different-in-2.0#error-handling | java.lang.IndexOutOfBoundsException: Index: 1, Size: 1
    at io.reactivex.plugins.RxJavaPlugins.onError(RxJavaPlugins.java:367)
    at io.reactivex.internal.observers.ConsumerSingleObserver.onSuccess(ConsumerSingleObserver.java:65)
    at io.reactivex.internal.operators.single.SingleJust.subscribeActual(SingleJust.java:30)
    at io.reactivex.Single.subscribe(Single.java:3603)
    at io.reactivex.Single.subscribe(Single.java:3589)
    at com.coffeemeetsbagel.DummyKt.main(Dummy.kt:7)
    at com.coffeemeetsbagel.DummyKt.main(Dummy.kt)
Caused by: java.lang.IndexOutOfBoundsException: Index: 1, Size: 1
    at java.util.Collections$SingletonList.get(Collections.java:4817)
    at com.coffeemeetsbagel.DummyKt$main.accept(Dummy.kt:8)
    at com.coffeemeetsbagel.DummyKt$main.accept(Dummy.kt)
    at io.reactivex.internal.observers.ConsumerSingleObserver.onSuccess(ConsumerSingleObserver.java:62)
    ... 5 more
Exception in thread "main" io.reactivex.exceptions.UndeliverableException: The exception could not be delivered to the consumer because it has already canceled/disposed the flow or the exception has nowhere to go to begin with. Further reading: https://github.com/ReactiveX/RxJava/wiki/What's-different-in-2.0#error-handling | java.lang.IndexOutOfBoundsException: Index: 1, Size: 1
    at io.reactivex.plugins.RxJavaPlugins.onError(RxJavaPlugins.java:367)
    at io.reactivex.internal.observers.ConsumerSingleObserver.onSuccess(ConsumerSingleObserver.java:65)
    at io.reactivex.internal.operators.single.SingleJust.subscribeActual(SingleJust.java:30)
    at io.reactivex.Single.subscribe(Single.java:3603)
    at io.reactivex.Single.subscribe(Single.java:3589)
    at com.coffeemeetsbagel.DummyKt.main(Dummy.kt:7)
    at com.coffeemeetsbagel.DummyKt.main(Dummy.kt)
Caused by: java.lang.IndexOutOfBoundsException: Index: 1, Size: 1
    at java.util.Collections$SingletonList.get(Collections.java:4817)
    at com.coffeemeetsbagel.DummyKt$main.accept(Dummy.kt:8)
    at com.coffeemeetsbagel.DummyKt$main.accept(Dummy.kt)
    at io.reactivex.internal.observers.ConsumerSingleObserver.onSuccess(ConsumerSingleObserver.java:62)
    ... 5 more

我读过the docs here但没有完全理解

我完全可以将 if {} else {} 或 try {} catch {} 添加到 onSuccess 消费者，但感觉代码有味道

我错了吗，if else/try catch 是在 onSuccess 中处理异常的最佳和/或预期方式吗？

Answer 1

您正在使用具有协议 onSuccess | onError 的 Single。因此，如果 onSuccess 崩溃，它无法在同一个观察者上调用 onError。

相比之下，Observable 具有协议 onNext* (onError|onComplete)?，因此允许崩溃 onNext 调用 onError。

你有几个选择 Single:

在订阅前将其转换为Observable，
在不可靠的 onSuccess 处理程序中添加 try-catch，
在较早的运算符中执行 mapping/transformation，例如 map，因此最终消费者不太可能崩溃。

RxJava UndeliverableException 如何处理onSuccess 消费异常？

RxJava UndeliverableException how to handle onSuccess consumer exception?

kotlin

rx-java

rx-java2