尝试使用RxJava和Kotlin从没有Wifi连接的Internet上获取数据时出错

Question

Hello guys I have in my BaseActivity the following function.

override fun <T> subscribeToInternet(observable: Observable<Response<BaseResponse<T>>>, observer: Observer<BaseResponse<T>>) {
    observable.subscribeOn(Schedulers.io())
            .observeOn(AndroidSchedulers.mainThread())
            .doOnSubscribe { observer.onSubscribe(it) }
            .doOnError {
                Log.d(TAG, it.message)
                observer.onError(it)
            }
            .doOnComplete { observer.onComplete() }
            .doOnNext {
                Log.d(TAG, "${it.body() ?: "no body"}")
                Log.d(TAG, "${it.errorBody()?.string() ?: "no error body"}")
                Log.d(TAG, it.code().toString())
                when {
                    it.code() == 401 -> {
                        view.userUnauthenticated()
                        observer.onNext(BaseResponse(false, "unauthenticated", null))
                        Log.d(TAG, "UNAUTHENTICATED")
                    }
                    it.code() == 423 -> {
                        view.userBlocked()
                        observer.onNext(BaseResponse(false, "blocked", null))
                        Log.d(TAG, "BLOCKED")
                    }
                    it.isSuccessful -> observer.onNext(it.body()!!)
                    it.code() == 429 -> observer.onNext(BaseResponse(false, "Too many attempts", null))
                    it.code() == 400 -> observer.onNext(BaseResponse(false, "Invalid Email or password", null))
                    else -> observer.onNext(BaseResponse(false, "", null))
                }
            }
            .subscribe()
}

And I handle the error in the observer's onNext() if the server returns a response, but the problem when there's no Internet connection on the device at all!! It throws the following exception

at io.reactivex.internal.operators.observable.ObservableDoOnEach$DoOnEachObserver.onError(ObservableDoOnEach.java:119)
    at io.reactivex.internal.observers.DisposableLambdaObserver.onError(DisposableLambdaObserver.java:64)
    at io.reactivex.internal.operators.observable.ObservableObserveOn$ObserveOnObserver.checkTerminated(ObservableObserveOn.java:276)
    at io.reactivex.internal.operators.observable.ObservableObserveOn$ObserveOnObserver.drainNormal(ObservableObserveOn.java:172)
    at io.reactivex.internal.operators.observable.ObservableObserveOn$ObserveOnObserver.run(ObservableObserveOn.java:252)

And this is the usage of the previously mentioned function

override fun sendLoginRequest(email: String, password: String, fcm_token: String) {
    subscribeToInternet(dataManager.sendLoginRequest(email, password, fcm_token), this)
}

override fun onComplete() {

}

override fun onSubscribe(d: Disposable) {
    DisposableManager.add(d)
}

override fun onNext(t: BaseResponse<LoginData>) {
    if(t.status) {
        Log.d(TAG, "${t.data}")
        dataManager.createLoginSession(t.data!!)
        view.loginSuccess()
    } else {
        Log.d(TAG, t.message)
        view.showError(t.message)
    }
}

override fun onError(e: Throwable) {
    view.showToastError()
    Log.d(TAG, e.message)
}

Answer 1

That problem is connected with the way you subscribing to observable. According to documentation when using subscribe() without passing action for handling errors, you should receive OnErrorNotImplementedException when source throws exceptions - that's because default exception handler from RxJavaPlugins is used.

To resolve that problem use one of overloaded subscribe methods with onError parameter. For example, public final Disposable subscribe(Consumer onNext, Consumer onError)