Observer

io.reactivex.Observer<T>

Known Indirect Subclasses

AsyncSubject<T>, BehaviorSubject<T>, DefaultObserver<T>, DisposableObserver<T>, PublishSubject<T>, ReplaySubject<T>, ResourceObserver<T>, SafeObserver<T>, SerializedObserver<T>, Subject<T>, TestObserver<T>, UnicastSubject<T>

AsyncSubject<T>	An Subject that emits the very last value followed by a completion event or the received error to Observers.
BehaviorSubject<T>	Subject that emits the most recent item it has observed and all subsequent observed items to each subscribed `Observer`.
DefaultObserver<T>	Abstract base implementation of an `Observer` with support for cancelling a subscription via `cancel()` (synchronously) and calls `onStart()` when the subscription happens.
DisposableObserver<T>	An abstract `Observer` that allows asynchronous cancellation by implementing Disposable.
PublishSubject<T>	Subject that, once an `Observer` has subscribed, emits all subsequently observed items to the subscriber.
ReplaySubject<T>	Replays events to Observers.
ResourceObserver<T>	An abstract `Observer` that allows asynchronous cancellation of its subscription and associated resources.
SafeObserver<T>	Wraps another Subscriber and ensures all onXXX methods conform the protocol (except the requirement for serialized access).
SerializedObserver<T>	Serializes access to the onNext, onError and onComplete methods of another Observer.
Subject<T>	Represents an Observer and an Observable at the same time, allowing multicasting events from a single source to multiple child Subscribers.
TestObserver<T>	An Observer that records events and allows making assertions about them.
UnicastSubject<T>	Subject that allows only a single Subscriber to subscribe to it during its lifetime.

Class Overview

Provides a mechanism for receiving push-based notifications.

After an Observer calls an Observable's subscribe method, first the Observable calls onSubscribe(Disposable) with a Disposable that allows cancelling the sequence at any time, then the Observable may call the Observer's onNext(T) method any number of times to provide notifications. A well-behaved Observable will call an Observer's onComplete() method exactly once or the Observer's onError(Throwable) method exactly once.

Summary

Public Methods
abstract void	onComplete() Notifies the Observer that the `Observable` has finished sending push-based notifications.
abstract void	onError(Throwable e) Notifies the Observer that the `Observable` has experienced an error condition.
abstract void	onNext(T t) Provides the Observer with a new item to observe.
abstract void	onSubscribe(Disposable d) Provides the Observer with the means of cancelling (disposing) the connection (channel) with the Observable in both synchronous (from within `onNext(Object)`) and asynchronous manner.

Public Methods

public abstract void onComplete ()

Notifies the Observer that the Observable has finished sending push-based notifications.

The Observable will not call this method if it calls onError(Throwable).

public abstract void onError (Throwable e)

Notifies the Observer that the Observable has experienced an error condition.

If the Observable calls this method, it will not thereafter call onNext(T) or onComplete().

Parameters

e	the exception encountered by the Observable

public abstract void onNext (T t)

Provides the Observer with a new item to observe.

The Observable may call this method 0 or more times.

The Observable will not call this method again after it calls either onComplete() or onError(Throwable).

Parameters

t	the item emitted by the Observable

public abstract void onSubscribe (Disposable d)

Provides the Observer with the means of cancelling (disposing) the connection (channel) with the Observable in both synchronous (from within onNext(Object)) and asynchronous manner.

Parameters

d	the Disposable instance whose `dispose()` can be called anytime to cancel the connection

Interfaces

Classes

Enums

Observer

Class Overview

See Also

Summary

Public Methods

public abstract void onComplete ()

public abstract void onError (Throwable e)

Parameters

public abstract void onNext (T t)

Parameters

public abstract void onSubscribe (Disposable d)

Parameters