Question

我在Crashlytics上遇到了很多与我为FirebaseRemoteConfig创建的rx-wrapper相关的NPE崩溃。

我的代码：

public Completable fetch() {
    remoteConfig.activateFetched();

    return Completable.create(e ->
            remoteConfig.fetch(cacheExpiration).addOnCompleteListener(
                    task -> {
                        if (task.isSuccessful()) {
                            Log.d(TAG, "Config fetched successfully");
                            remoteConfig.activateFetched();
                            if (!e.isDisposed()) {
                                e.onComplete();
                            }
                        } else {
                            if (!e.isDisposed()) {
                                Log.e(TAG, "Config fetch error", task.getException());
                                e.onError(task.getException());
                            }
                        }
                    }));
}

然后我订阅它：

    composite.clear();

    composite.add(
            helper.fetch()
                    .subscribeOn(Schedulers.io())
                    .observeOn(AndroidSchedulers.mainThread())
                    .subscribeWith(new DisposableCompletableObserver() {
                        @Override
                        public void onComplete() {
                            Timber.tag(TAG).d("Remote config fetched");
                        }

                        @Override
                        public void onError(@NonNull Throwable throwable) {
                            Timber.tag(TAG).d(throwable, "Remote config fetch error");
                        }
                    })
    );

我遇到了3种类型的崩溃：

Crash #1
        Fatal Exception: java.lang.NullPointerException
           at io.reactivex.internal.operators.completable.CompletableCreate.subscribeActual(CompletableCreate.java:36)
           at io.reactivex.Completable.subscribe(Completable.java:1635)
           at io.reactivex.internal.operators.completable.CompletableSubscribeOn$SubscribeOnObserver.run(CompletableSubscribeOn.java:64)
           at io.reactivex.Scheduler$DisposeTask.run(Scheduler.java:452)
           at io.reactivex.internal.schedulers.ScheduledRunnable.run(ScheduledRunnable.java:61)
           at io.reactivex.internal.schedulers.ScheduledRunnable.call(ScheduledRunnable.java:52)
           at java.util.concurrent.FutureTask.run(FutureTask.java:237)
           at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.access$201(ScheduledThreadPoolExecutor.java:152)
           at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.run(ScheduledThreadPoolExecutor.java:265)
           at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1112)
           at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:587)
           at java.lang.Thread.run(Thread.java:841)


Crash #2
    Fatal Exception: java.lang.NullPointerException
       at io.reactivex.internal.operators.completable.CompletableSubscribeOn.subscribeActual(CompletableSubscribeOn.java:36)
       at io.reactivex.Completable.subscribe(Completable.java:1635)
       at io.reactivex.internal.operators.completable.CompletableObserveOn.subscribeActual(CompletableObserveOn.java:34)
       at io.reactivex.Completable.subscribe(Completable.java:

Crash #3
    Fatal Exception: java.lang.NullPointerException
       at io.reactivex.internal.operators.completable.CompletableObserveOn$ObserveOnCompletableObserver.onSubscribe(CompletableObserveOn.java:68)
       at io.reactivex.internal.operators.completable.CompletableSubscribeOn.subscribeActual(CompletableSubscribeOn.java:36)
       at io.reactivex.Completable.subscribe(Completable.java:1635)
       at io.reactivex.internal.operators.completable.CompletableObserveOn.subscribeActual(CompletableObserveOn.java:34)
       at io.reactivex.Completable.subscribe(Completable.java:1635)

奇怪的是，崩溃只发生在Android 4上，主要是4.4和4.1。

Answer 1

所有这些错误的共同点是，它们似乎是由null引起的，其中CompletableObserver是预期的。

鉴于subscribeWith获取有效对象，发生这种情况的唯一方法是通过错误配置RxJavaPlugin.onSubscribe挂钩，它可以包装观察者，因此由于某种原因用{替换观察者{1}}。

我建议使用反射检查null类中的onCompletableSubscribe字段，看看是否有一些回调可能会对这些java版本表现得很奇怪。

仅在Android 4上完成创建NPE

1 个答案: