我正在使用RXJava（RXAndroid）来序列化一系列AWS s3传输请求。
我正在使用AWS TransferUtility，它提供了一个获取进度和错误通知的异步TransferListener。
我很难传播这些错误。
我的代码看起来像这样
for (final String subscription : subscriptions) {
Observable<String> thisObservable = new Observable<String>() {
@Override
protected void subscribeActual(Observer<? super String> observer) {
new S3Loader(subscription, observer).load();
// The S3Loader uses AWS TransferListener to call onNext and onError of the observers
}
};
observables.add(thisObservable);
Log.v(this, "Added %s", subscription);
}
Observable.concat(observables)
.subscribeOn(Schedulers.io())
.observeOn(AndroidSchedulers.mainThread())
.subscribe(new Observer<String>() {
@Override
public void onSubscribe(@NonNull Disposable d) {
Log.v(OperationalStatusFragment.this, "Subscribed...");
}
@Override
public void onNext(@NonNull String s) {
Log.v(OperationalStatusFragment.this, "Started weather operation \"%s\"", s);
}
@Override
public void onError(@NonNull Throwable e) {
Log.e(OperationalStatusFragment.this, "An error happened...");
}
@Override
public void onComplete() {
Log.v(OperationalStatusFragment.this, "Completed...");
}
}
);
基本上，当TransferListebner中的代码调用onError时，将调用观察者onError块，但是应用程序在此之后崩溃，因为我得到了抛出但是包含在UndeliverableException中的相同异常。
感觉这与transferListener的异步性质有关（就像我同步调用相同的onError方法一样，它按预期工作。
知道出了什么问题吗？
编辑1：这是堆栈跟踪的样子
06-02 18:49:23.286 11687-11687/com.ironbird.fav2 E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.ironbird.fav2, PID: 11687
io.reactivex.exceptions.UndeliverableException: java.io.IOException: Got failed while downloading weather DB for "FRxxx" from "weather/06/weather_FRxxx.db" to "/data/user/0/com.ironbird.fav2/app_weather/FRxxx.db" (transfer #568)
at io.reactivex.plugins.RxJavaPlugins.onError(RxJavaPlugins.java:349)
at io.reactivex.internal.operators.observable.ObservableConcatMap$ConcatMapDelayErrorObserver$DelayErrorInnerObserver.onError(ObservableConcatMap.java:509)
at com.ironbird.fav2.weather.S3loader$1.onStateChanged(S3loader.java:79)
at com.amazonaws.mobileconnectors.s3.transferutility.TransferStatusUpdater$1.run(TransferStatusUpdater.java:172)
at android.os.Handler.handleCallback(Handler.java:751)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:154)
at android.app.ActivityThread.main(ActivityThread.java:6119)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:886)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:776)
Caused by: java.io.IOException: Got failed while downloading weather DB for "FRxxx" from "weather/06/weather_FRxxx.db" to "/data/user/0/com.ironbird.fav2/app_weather/FRxxx.db" (transfer #568)
at com.ironbird.fav2.weather.S3loader$1.onStateChanged(S3loader.java:79)
at com.amazonaws.mobileconnectors.s3.transferutility.TransferStatusUpdater$1.run(TransferStatusUpdater.java:172)
at android.os.Handler.handleCallback(Handler.java:751)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:154)
at android.app.ActivityThread.main(ActivityThread.java:6119)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:886)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:776)
编辑2：这是S3loader.load（）的样子：
public void load() {
observer.onNext(subscription);
AmazonS3Client s3Client = new AmazonS3Client();
TransferUtility transferUtility = new TransferUtility(s3Client, context);
TransferObserver observer = transferUtility.download(BUCKET, subscription, file);
observer.setTransferListener(new TransferListener() {
@Override
public void onStateChanged(int id, TransferState state) {
if (state == TransferState.COMPLETED) {
observer.onComplete();
} else if (state == TransferState.FAILED) {
observer.onError(new IOException("An error happened"));
}
}
@Override
public void onProgressChanged(int id, long bytesCurrent, long bytesTotal) {
}
@Override
public void onError(int id, Exception e) {
observer.onError(e);
}
});
}