使用Rxjava进行改造和领域

Question

i want to use the cached data in realm then update the data from server using retrofit. i managed that by the following:

public void getNotifications() {
    Observable.concat(getCashedNotifications(), downloadNotification())
            .subscribe(new Action1<List<Notification>>() {
                @Override
                public void call(List<Notification> notifications) {
                    setSize(notifications.size() + "");
                }
            });
}

private Observable<List<Notification>> getCashedNotifications() {
    return Observable.just(mRealm.copyFromRealm(mRealm.where(Notification.class).findAll()));
}

private Observable<List<Notification>> downloadNotification() {
    return mApiHandler.createRetrofitService(NotificationServices.class)
            .getNotificationByUser(10)
            .subscribeOn(Schedulers.newThread())
            .observeOn(AndroidSchedulers.mainThread())
            .doOnNext(new Action1<NotificationResponse>() {
                @Override
                public void call(final NotificationResponse notificationResponse) {
                    setLoading(false);
                    mRealm.executeTransactionAsync(new Realm.Transaction() {
                        @Override
                        public void execute(Realm realm) {
                            realm.copyToRealmOrUpdate(notificationResponse.getResult().getData().getNotifications());
                        }
                    });
                }
            })
            .map(new Func1<NotificationResponse, List<Notification>>() {
                @Override
                public List<Notification> call(NotificationResponse notificationResponse) {
                    if (notificationResponse.getResult() != null) {
                        return notificationResponse.getResult().getData().getNotifications();
                    } else {
                        return new ArrayList<>();
                    }
                }
            });
}

my problem is to get the current status like : 1- if there is no data in realm show progress 2- if there is no data and no network show error dialog 3- if there is data in realm and no network show the data from realm only 4- if there is no data in realm and no data from retrofit show no data state

any idea how to know the resuslts from concat are from ? (retrofit or realm)

Answer 1

what i ended up with is to edit the getNotifications method to the following

public void getNotifications() {
    setNoData(false);
    setLoading(false);
    if (ConectivityUtils.isDeviceConnectedToNetwork(mContext)) {
        if (mRealm.where(Notification.class).count() > 0) {
            Observable.concat(getCashedNotifications(), downloadNotification())
                    .subscribe(new Action1<List<Notification>>() {
                        @Override
                        public void call(List<Notification> notifications) {
                            setSize(notifications.size() + "");
                        }
                    });
        } else {
            // show progress
            setLoading(true);
            downloadNotification().subscribe(new Action1<List<Notification>>() {
                @Override
                public void call(List<Notification> notifications) {
                    setLoading(false);
                    if (notifications.size() > 0) {
                        setSize(notifications.size() + "");
                    } else {
                        // no data in realm and retrofit
                        setNoData(true);
                        setErrorMessage("No data");
                    }
                }
            });
        }
    } else {
        if (mRealm.where(Notification.class).count() > 0) {
            getCashedNotifications().subscribe(new Action1<List<Notification>>() {
                @Override
                public void call(List<Notification> notifications) {
                    setSize(notifications.size() + "");
                }
            });
        } else {
            //show no network
            setNoData(true);
            setErrorMessage("No Network");
        }
    }
}

but i believe that there is better and cleaner solution than this