RxJava 使 retryWhen() 触发 onError() 方法

Question

我有一个 class 的 RxJava 实现，用于从 API 下载两个资源。我做了一些 rx 以允许它在不满足 api/connection 要求时重试或重复。但是，我无法让 retryWhen() 在尝试超过 3 次后触发 onError()。

问题/帮助

请检查我的代码并帮助我解决这个问题。

注意

我通过阅读这两篇文章实现了 Rx。 article 1, article 2

SplashPresenter.class

public class SplashPresenter implements SplashContract.Presenter {

    private static final String TAG = SplashPresenter.class.getName();
    private static final int RETRY_TIMEOUT = 10;
    private static final int STOP_RETRY_TIME = 3;
    private static final int START_RETRY_TIME = 1;


    private SplashContract.View mView;

    @Override
    public void init(SplashContract.View view) {
        this.mView = view;
    }

    @Override
    public void onResume() {

        GetRemoteReceiverRelationshipSpec relationSpec = new GetRemoteReceiverRelationshipSpec();
        GetRemoteIncompleteReasonSpec reasonSpec = new GetRemoteIncompleteReasonSpec();

        Observable<RepoResult<ArrayList<IncompleteReasonViewModel>>> queryReason =
                Repository.getInstance().query(reasonSpec);

        Repository.getInstance().query(relationSpec)
                .concatMap(result -> queryReason)
                .repeatWhen(complete -> complete
                        .zipWith(Observable.range(START_RETRY_TIME, STOP_RETRY_TIME), (v, i) -> i)
                        .flatMap(repeatCount -> {
                            Log.i(TAG, "Repeat attempt: " + repeatCount);
                            mView.showLoadingDialog();
                            return Observable.timer(RETRY_TIMEOUT,
                                    TimeUnit.SECONDS);
                        }))
                .takeUntil(RepoResult::isSuccess)
                .retryWhen(error -> error
                        .zipWith(Observable.range(START_RETRY_TIME, STOP_RETRY_TIME), (v, i) -> i)
                        .flatMap(retryCount -> {
                            Log.i(TAG, "Retry attempt: " + retryCount);
                            mView.showLoadingDialog();
                            if (mView.getCommunicator() != null) {
                                mView.getCommunicator().onConnectionFail(retryCount);
                            }
                            return Observable.timer(RETRY_TIMEOUT,
                                    TimeUnit.SECONDS);
                        }))
                .filter(RepoResult::isSuccess)
                .observeOn(AndroidSchedulers.mainThread())
                .subscribe(
                        result -> Log.i(TAG, "onNext()"),
                        err -> {
                            Log.i(TAG, "onError()");
                            if (mView.getCommunicator() != null) {
                                mView.dismissLoadingDialog();
                                mView.getCommunicator().onSplashScreeDismissError();
                            }
                        },
                        () -> {
                            Log.i(TAG, "onComplete()");
                            if (mView.getCommunicator() != null) {
                                mView.dismissLoadingDialog();
                                mView.getCommunicator().onSplashScreenSuccessDismiss();
                            }
                        }
                );
    }

    @Override
    public void onPause() {

    }
}

Answer 1

之前写类似代码的时候，我手动把Observable.error()扔到flatMap

.flatMap(retryCount -> {
    if (retryCount >= STOP_RETRY_TIME) {
        return Observable.error(someException);
    }
    return Observable.timer(RETRY_TIMEOUT, TimeUnit.SECONDS);
 }))

Answer 2

要在重试后保留 throwable（而不是发出自定义的），return当 retryCount 超过指定限制时，一个带有来自 zipWith 运算符的适当错误的 Observable。

.retryWhen(error -> {
                Observable<Integer> range = Observable.range(START_RETRY_TIME, STOP_RETRY_TIME);
                Observable<Observable<Long>> zipWith = error.zipWith(range, (e, i) ->
                        i < STOP_RETRY_TIME ?
                                Observable.timer(i, TimeUnit.SECONDS) :
                                Observable.error(e));
                return Observable.merge(zipWith);
            });

Answer 3

如果达到重试限制，将重试计数器和错误传递给 Pair 对象，从 pair 对象获取异常并引发它。

source.retryWhen(errors -> errors
                        .zipWith(Observable.range(1, REQUEST_RETRY), Pair::new)
                        .flatMap(errPair -> {
                            int retryTime = errPair.second;
                            if (retryTime < REQUEST_RETRY) {
                                return Observable.timer(retryTime * RETRY_DELAY, TimeUnit.MILLISECONDS);
                            } else {
                                return Observable.error(errPair.first);
                            }
                        })
                        .doOnError(this::handleError));

RxJava 使 retryWhen() 触发 onError() 方法

RxJava make retryWhen() fire to onError() method

android

rx-java

rx-android