Recently I have been working on RxJava 2 and I have tested the Observable.interval()
subscription = Observable.interval(1, TimeUnit.MILLISECONDS, Schedulers.io()).observeOn(AndroidSchedulers.mainThread());
subscription.subscribe(new Observer<Long>() {
#Override
public void onSubscribe(Disposable d) {
}
#Override
public void onNext(Long aLong) {
//binding.appBar.mainContent.msg.setText(aLong+"");
}
#Override
public void onError(Throwable e) {
}
#Override
public void onComplete() {
}
});
Observable is started after activity's onCreate method. And I am logging the output through onNext() method. And I have a Stop Button. When it is triggered I want to stop subscription flow.
Even after the stop button is clicked the log keeps on going.
stop.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
if (subscription != null) {
subscription.unsubscribeOn(Schedulers.io());
}
}
});
You have subscribed with an Observer, which means you have to keep a reference to the actual Disposable from onSubscribe(Disposable) callback, and later perform Disposable#dispose() on that object.
private Disposable disposable;
...
Observable.interval(1, TimeUnit.MILLISECONDS, Schedulers.io())
.observeOn(AndroidSchedulers.mainThread())
.subscribe(
new Observer() {
#Override public void onSubscribe(Disposable d) {
disposable = d;
}
// other callbacks here
});
disposable.dispose();
Instead you can change your subscription to following:
Disposable disposable = Observable.interval(1, TimeUnit.MILLISECONDS, Schedulers.io())
.observeOn(AndroidSchedulers.mainThread())
.subscribe(new Consumer() {
#Override public void accept(Long aLong) throws Exception {
// onNext
}
}, new Consumer() {
#Override public void accept(Throwable throwable) throws Exception {
// onError
}
}, new Action() {
#Override public void run() throws Exception {
// onComplete
}
});
disposable.dispose();
Related
I need help for RxJava. Everything is working fine. But I want to call onNext manually in my other method.
Observable<Data> mylist = Observable.fromIterable(datalist);
mylist.subscribeOn(Schedulers.io())
.observeOn(AndroidSchedulers.mainThread())
.buffer(6)
.subscribe(new Observer<List<Data>>() {
#Override
public void onSubscribe(Disposable d) { }
#Override
public void onNext(List<Data> list) {
myadapter.addData(list);
}
#Override
public void onError(Throwable e) {}
#Override
public void onComplete() { fetchNextPage(); }
});
Like this:
OnloadMore() {
onNext()
}
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
Hi fellow programmers,
I am using RxAndroid to make an interval API call every 3 seconds when a button is pressed.
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);
}
});
My question is if there is a way to make the button (or it's onClick listener) an Observable too and chain it with the others.
Something like buttonFetchIntervalWeather.subscribe(fetchWeatherInterval);
Use RxBinding
Subscription s = RxView.clicks(button)
.throttleFirst(5, TimeUnit.SECONDS) // maybe you want to ignore multiple clicks
.flatMap(foo -> fetchWeatherInterval)
.subscribe(displayWeatherInterval);
throttleFirst just stops further events for next 5 seconds so if user clicks the button multiple times, the same fetchWeatherInterval won't be triggered again, for the next 5 seconds, of course.
flatMap converts output of one observable into another observable, in this case from click event to fetchWeatherInterval. Read the docs if you need more info.
Also, RxJava2 works as well, I just answered this for RxJava1. Just change Subscription to Disposable.
Using Observable.create():
Observable.create(new Action1<Emitter<View>>() {
#Override
public void call(Emitter<View> emitter) {
emitter.setCancellation(new Cancellable() {
#Override
public void cancel() throws Exception {
button.setOnClickListener(null);
emitter.onCompleted();
}
});
button.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
emitter.onNext(v);
}
});
}
}, Emitter.BackpressureMode.DROP);
Or with lambda:
Observable.create(emitter -> {
emitter.setCancellation(() -> {
button.setOnClickListener(null);
emitter.onCompleted();
});
button.setOnClickListener(emitter::onNext);
}, Emitter.BackpressureMode.DROP);
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've an Observable something like this:
#GET("endpoint")
Observable<Something> getSomething();
and Subscriber like this
Subscriber<Something> somethingSubscriber = new Subscriber<Something>() {
public void onCompleted() {
}
public void onError(Throwable e) {
//handle exceptions
}
public void onNext() {
//do something
}
In my OnClickListener associated with a button, i make a subscription
getSomething()
.subscribeOn(Schedulers.newThread())
.observeOn(AndroidSchedulers.mainThread())
.subscribe(somethingSubscriber);
If i don't have an internet connection, onError is called and i do some exception handling. when I press the button again (assume i want to retry), the callback methods do not get called.
I want that onNext / onError callbacks get called everytime I press the button.
There is extention for RxJava. It has a lot of "cool tools", but for handling retrofit errors you can use ResponseOrError class.
So in you case it would looks like:
final PublishSubject<Object> clickSubject = PublishSubject.create();
final Observable<ResponseOrError<Something>> responseOrErrorObservable = clickSubject
.flatMap(new Func1<Object, Observable<ResponseOrError<Something>>>() {
#Override
public Observable<ResponseOrError<Something>> call(Object o) {
return getSomething()
.subscribeOn(Schedulers.newThread())
.observeOn(AndroidSchedulers.mainThread())
.compose(ResponseOrError.<Something>toResponseOrErrorObservable());
}
})
.replay(1)
.refCount();
final Observable<Throwable> error = responseOrErrorObservable
.compose(ResponseOrError.<Something>onlyError())
.subscribe(new Action1<Segment>() {
#Override
public void call(Throwable throwable) {
// what to do on error, some toast or what ever yu need
}
});
final Observable<UserInfoResponse> success = responseOrErrorObservable
.compose(ResponseOrError.<Something>onlySuccess())
.subscribe(new Action1<Something>() {
#Override
public void call(Something some) {
// code what to do on success
}
});
And now, into onClick you just need to put clickSubject.onNext(null)
.replay(1).refCount(); needed because there are 2 Observables that uses responseOrErrorObservable, so without it retrofit request will "happens" two times.
You are reusing the same Subscriber. Once you get the onError or a result (so it completes) the subscriber is unsubscribed. Try to pass every time a new subscriber.
use this code
button.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
getSomething()
.subscribeOn(Schedulers.newThread())
.observeOn(AndroidSchedulers.mainThread())
.subscribe(new Action1<Something>() {
#Override
public void call(Something something) {
//do something
}
},
new Action1<Throwable>() {
#Override
public void call(Throwable throwable) {
//handle exceptions
}
},
new Action0() {
#Override
public void call() {
}
});
}
});
Addition
or
replace this
Subscriber<Something> somethingSubscriber = new Subscriber<Something>() {
public void onCompleted() {
}
public void onError(Throwable e) {
//handle exceptions
}
public void onNext() {
//do something
}
};
to
Subscriber<String> somethingSubscriber = new Subscriber<String>() {
#Override
public void onCompleted() {
}
#Override
public void onError(Throwable e) {
}
#Override
public void onNext(String s) {
}
};
In my Case onNext() and onError() methods are not getting called because of my model class wrong parsing, I was taking a double object as Integer so NumberFormatException was thrown and nothing was happening after getting the result from retrofit.