android - 如何使用 RxJava 逃离这个回调 hell

Question

subscriptionSet = provider.removeGeofences(mGeofencePendingIntent).observeOn(AndroidSchedulers.mainThread()).subscribe(new Subscriber<Status>() {
            @Override
            public void onCompleted() {

            }

            @Override
            public void onError(Throwable e) {
                Log.d(TAG, "onError() called with: " + "e = [" + e + "]");
            }

            @Override
            public void onNext(Status status) {
                Prefs.geofence.clear();
                subscriptionAdd = statusObservable.observeOn(AndroidSchedulers.mainThread()).subscribe(new Subscriber<Status>() {
                    @Override
                    public void onCompleted() {

                    }

                    @Override
                    public void onError(Throwable e) {
                        Log.d(TAG, "onError() called with: " + "e = [" + e + "]");
                    }

                    @Override
                    public void onNext(Status status) {
                        Prefs.geofence.set(...);
                    }
                });
            }
        });

我正在尝试使用很棒的 Android-ReactiveLocation为地理围栏实现类似于“设置”的操作 - 例如，如果已经存在，则清除它，然后将其设置到所需位置，以便始终有一个地理围栏。

嗯，我也在尝试学习 RxJava，所以我听说 RxJava 可以解决回调 hell 问题，那么它如何解决我的问题呢？

谢谢!

Answer 1

当你想使用连续订阅时，你应该使用flatMap操作符。这样你的问题就可以简化为:

subscription = provider.removeGeofences(mGeofencePendingIntent)
            .flatMap(new Func1<Status, Observable<Status>>() {
                @Override
                public Observable<Status> call(Status status) {
                    //after the first subscription
                    Prefs.geofence.clear();
                    return statusObservable;
                }
            })
            .observeOn(AndroidSchedulers.mainThread())
            .subscribe(new Action1<Status>() {
                @Override
                public void call(Status status) {
                    //after the second subscription
                    Prefs.geofence.set(...);
                }
            }, new Action1<Throwable>() {
                @Override
                public void call(Throwable throwable) {
                    Log.d(TAG, "onError() called with: " + "e = [" + e + "]");
                }
            });