I'm trying to run a long running task that might fail for some objects in a list I tried retry but it resubscribes to the entire list of observables. I can do nested subscriptions but it seems wrong. Is there any better solution than nesting subscriptions?
Here is my implementation:
public Observable<ReportItemModel> deferReports() {
return Observable.defer(new Callable<ObservableSource<? extends ReportItemModel>>() {
#Override
public ObservableSource<? extends ReportItemModel> call() throws Exception {
return Observable.fromIterable(getReports())
.map(new Function<Report, ReportItemModel>() {
#Override
public ReportItemModel apply(Report report) throws Exception {
return report.getReport();
}
});
}
});
}
reportFactory.deferReports()
.observeOn(AndroidSchedulers.mainThread())
.subscribeOn(Schedulers.io())
.retry()
.subscribe(new Observer<ReportItemModel>() {
#Override
public void onSubscribe(Disposable d) {
}
#Override
public void onNext(ReportItemModel value) {
Log.d(TAG,value.toString());
}
#Override
public void onError(Throwable e) {
}
#Override
public void onComplete() {
}
});
Related
While inflating Android view I load a bunch of stuff from the background thread and inflate some views based on network responses. So I am trying to defer some of that tasks using RxJava like this
Single.fromCallable(() -> savedInstanceState)
.delay(50,TimeUnit.MICROSECONDS,AndroidSchedulers.mainThread())
.flatMapCompletable(this::loadVideos)
.subscribeOn(Schedulers.io())
.observeOn(AndroidSchedulers.mainThread())
.subscribe(new CompletableObserver() {
#Override
public void onSubscribe(Disposable d) {
Timber.d("on Subscribe");
}
#Override
public void onComplete() {
Timber.d("on onComplete");
}
#Override
public void onError(Throwable e) {
Timber.d("on onError");
}
});
And the loadVideos method is like this:
private Completable loadVideos(Bundle savedInstanceState) {
return Completable.fromAction(() -> {
videoPresenter.loadVideos(savedInstance);
});
}
What I am finding is onSubscribe() certainly gets called, but method videoPresenter.loadVideos never gets called. Would appreciate if anyone can point out what I am doing wrong.
For my testing, I implemented following test that seems to work...
public class DelayTest {
public static void main(String[] args) throws InterruptedException {
Single.fromCallable(() -> "hello")
.delay(50, TimeUnit.MICROSECONDS)
.flatMapCompletable(new Function<String, CompletableSource>() {
#Override
public CompletableSource apply(String s) throws Exception {
return getFlatMapCompletable();
}
})
.subscribe(new CompletableObserver() {
#Override
public void onSubscribe(Disposable d) {
System.out.println("In onSubscribe");
}
#Override
public void onComplete() {
System.out.println("In onComplete");
}
#Override
public void onError(Throwable e) {
System.out.println("In onError");
}
});
Thread.sleep(200L);
}
private static Completable getFlatMapCompletable() {
return Completable.fromAction(new Action() {
#Override
public void run() throws Exception {
System.out.println("In flatmapCompletable");
}
});
}
}
Delay operator in RxJava is executed in another thread. So the rest of the execution does not wait for this one to be finished.
Take a look to some examples https://github.com/politrons/reactive/blob/master/src/test/java/rx/observables/utils/ObservableDelay.java
Few days ago I have faced with the treading rx problem. I was thinking how the rxJava threading works. This code didn't want to run on another thread.
mAPIInterface.getAllProjects(accessToken)
.subscribeOn(Schedulers.newThread())
.observeOn(AndroidSchedulers.mainThread())
.subscribe(new Observer<List<Project>>() {
#Override
public void onSubscribe(#NonNull Disposable d) {
mView.showLoadProgress();
}
#Override
public void onNext(#NonNull List<Project> allProjects) {
projects = allProjects;
mView.hideLoadProgress();
mView.onProjectsLoaded();
}
#Override
public void onError(#NonNull Throwable e) {
mView.hideLoadProgress();
mView.onProjectsLoadError();
}
#Override
public void onComplete() {
}
});
Then I have find the solution but I'm still not sure if it's ok. That's look like there are some more good solution:
mAPIInterface.getAllProjects(accessToken)
.subscribeOn(Schedulers.newThread())
.map(new Function<List<Project>, List<Project>>() {
#Override
public List<Project> apply(#NonNull List<Project> projects) throws Exception {
return projects;
}
})
.observeOn(AndroidSchedulers.mainThread())
.subscribe(new Observer<List<Project>>() {
#Override
public void onSubscribe(#NonNull Disposable d) {
mView.showLoadProgress();
}
#Override
public void onNext(#NonNull List<Project> allProjects) {
projects = allProjects;
mView.hideLoadProgress();
mView.onProjectsLoaded();
}
#Override
public void onError(#NonNull Throwable e) {
mView.hideLoadProgress();
mView.onProjectsLoadError();
}
#Override
public void onComplete() {
}
});
With that map() middleware it works. But should I use that everytime when I need to run the process on another thread?
I want to send multiple requests over the network and this tutorial
helped but i'm stuck at the latter part .
seems i'm expected to return a value(OrderValues) from onSubscribe,onNext,....
since apply function returns a value. But ....,onNext returns void by default.
Any help?Here is my piece of code
Observable<Restaurant> orderRestaurant= IdentityClient.getAPIService()
.getRestaurantById(restaurantId)
.subscribeOn(Schedulers.newThread())
.observeOn(AndroidSchedulers.mainThread());
Observable<Menu> orderMenu= IdentityClient.getAPIService()
.getMenuById(menuId)
.subscribeOn(Schedulers.newThread())
.observeOn(AndroidSchedulers.mainThread());
Observable<User> orderUser= IdentityClient.getAPIService()
.getUserById(userId)
.subscribeOn(Schedulers.newThread())
.observeOn(AndroidSchedulers.mainThread());
Observable<OrderValues> combineValues=Observable.zip(orderRestaurant,
orderMenu, orderUser,
new Function3<Restaurant, Menu, User, OrderValues>() {
#Override
public OrderValues apply(Restaurant restaurant, Menu menu, User user)
throws Exception {
return new OrderValues(restaurant,menu,user);
}
I get an error here "cannot resolve method 'subscribe anonymous
org.reactivestreams.Subscriber(....OrderValues)
}).subscribe(new Subscriber<OrderValues>() {
#Override
public void onSubscribe(Subscription s) {
}
#Override
public void onNext(OrderValues orderValues) {
}
#Override
public void onError(Throwable t) {
}
#Override
public void onComplete() {
}
});
I'm assuming that you are using RxJava 2.
Use Observer instead of Subscriber. And also do not assign the result to a new Observable (you called it combineValues).
private void myMethod() {
Observable.zip(orderRestaurant, orderMenu, orderUser, new Function3<Restaurant, Menu, User, OrderValues>() {
#Override
public OrderValues apply(#NonNull Restaurant restaurant, #NonNull Menu menu, #NonNull User user) throws Exception {
return new OrderValues(restaurant, menu, user);
}
}).subscribe(new Observer<OrderValues>() {
#Override
public void onSubscribe(Disposable d) {
}
#Override
public void onNext(OrderValues orderValues) {
}
#Override
public void onError(Throwable e) {
}
#Override
public void onComplete() {
}
});
}
}
Am doing a weather API call every 3secs and append the result to a textView using showWeather("weather") but I am sure there is a better way to do it. Am not sure why I need create Class Func1 but did because map required it. Also is there a way to shorten observer? I don't use lamda unfortunately. Any suggestions?
Observer myObserver = new Observer<String>() {
#Override
public void onError(Throwable e) {
Logger.getLogger(getClass().getName()).log(Level.SEVERE, null, e);
}
#Override
public void onComplete() {
}
#Override
public void onSubscribe(Disposable d) {
}
#Override
public void onNext(String value) {
showWeather(value);
}
};
class Func1<T, T1> implements io.reactivex.functions.Function<Long, String > {
#Override
public String apply(Long aLong) throws Exception {
return getJSON("http://samples.openweathermap.org/data/2.5/weather?q=London,uk&appid=b1b15e88fa797225412429c1c50c122a1",300);
}
}
Observable.interval(3, TimeUnit.SECONDS)
.map(new Func1<Long, Observable<String>>() {
}).observeOn(AndroidSchedulers.mainThread()).subscribe(myObserver);
I tried :
Observable
.interval(3, SECONDS)
.subscribeOn(Schedulers.io())
.fromCallable(new Callable<String>() {
#Override
public String call() throws Exception {
return getJSON("http://samples.openweathermap.org/data/2.5/weather?q=London,uk&appid=b1b15e88fa797225412429c1c50c122a1", 300);
}
})
.observeOn(AndroidSchedulers.mainThread())
.subscribe(myObserver)
But I get :
03-07 21:47:25.982 21181-21181/com.alex.rxandroidexamples E/imerExampleFragment$1$1: null
android.os.NetworkOnMainThreadException
at android.os.StrictMode$AndroidBlockGuardPolicy.onNetwork(StrictMode.java:1273)
Also how do I unsubscribe onPause or onPause?
I found out the best way to do this is :
private final CompositeDisposable disposables = new CompositeDisposable();
Observable fetchWeatherInterval = Observable.interval(3, TimeUnit.SECONDS)
.map(new Function<Long, String>() {
#Override
public String apply(Long aLong) throws Exception {
return getWeather("http://samples.openweathermap.org/data/2.5/weather?", "London,uk", "b1b15e88fa797225412429c1c50c122a1");
}
})
.subscribeOn(Schedulers.io())
.observeOn(AndroidSchedulers.mainThread());
Observer displayWeatherInterval = new Observer<String>() {
#Override
public void onError(Throwable e) {
Log.e("Throwable ERROR", e.getMessage());
}
#Override
public void onComplete() {
}
#Override
public void onSubscribe(Disposable d) {
disposables.add(d);
}
#Override
public void onNext(String value) {
textViewWeatherInterval.append(value);
}
};
buttonFetchIntervalWeather.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
fetchWeatherInterval.subscribe(displayWeatherInterval);
}
});
I have the following code. It's basically an attempt to send all data from a specific SQLite table to DynamoDB:
Observable.create(new Observable.OnSubscribe<Area>() {
#Override
public void call(Subscriber<? super Area> subscriber) {
try {
for (Area item : areaDao.listAll()) {
subscriber.onNext(item);
}
subscriber.onCompleted();
} catch (Exception e) {
subscriber.onError(e);
}
}
}).flatMap(new Func1<Area, Observable<Area>>() {
#Override
public Observable<Area> call(Area area) {
dynamoDBMapper.save(area);
return Observable.just(area);
}
}).observeOn(
AndroidSchedulers.mainThread()
).doOnError(new Action1<Throwable>() {
#Override
public void call(Throwable throwable) {
Log.w("AreaHandler", "Could not upload area", throwable);
}
}).doOnCompleted(new Action0() {
#Override
public void call() {
Toast.makeText(ctx, R.string.toast_upload_successful, Toast.LENGTH_SHORT).show();
}
}).subscribeOn(
Schedulers.io()
).subscribe(new Action1<Area>() {
#Override
public void call(Area area) {
areaDao.delete(area.getId());
}
});
I'm trying to run it on an emulator with disabled Internet connectivity, and what happens is that the Dynamo client does a couple of (failed) retries, then an exception is thrown and it crashes the app. From what I read in the docs, the exception should be swallowed by doOnError instead of being let out to the wild and killing the process.
What am I missing?
You are grabbing the error in the wrong place. doOnError is for side effects. It does not handle the error.
Option 1. Pass in two Action1
Observable.just(1, 2, 3)
.subscribe(
new Action1<Integer>() {
#Override
public void call(Integer integer) {
System.out.println(integer);
}
},
new Action1<Throwable>() {
#Override
public void call(Throwable throwable) {
System.err.print(throwable);
}
});
Option 2: Pass in an Observer
Observable.just(1, 2, 3)
.subscribe(new Observer<Integer>() {
#Override
public void onCompleted() {
}
#Override
public void onError(Throwable throwable) {
System.err.print(throwable);
}
#Override
public void onNext(Integer integer) {
System.out.println(integer);
}
});