A controller with the stream it controls.

This controller allows sending data, error and done events onitsstream.

This class can be used to create a simple stream that otherscan listen on, and to push events to that stream.

It's possible to check whether the stream is paused or not, and whetherit has subscribers or not, as well as getting a callback when either ofthese change.

Example:

final streamController = StreamController(  onPause: () => print('Paused'),  onResume: () => print('Resumed'),  onCancel: () => print('Cancelled'),  onListen: () => print('Listens'),);streamController.stream.listen(  (event) => print('Event: $event'),  onDone: () => print('Done'),  onError: (error) => print(error),);

To check whether there is a subscriber on the stream, usehasListener.

var hasListener = streamController.hasListener; // true

To send data events to the stream, useadd oraddStream.

streamController.add(999);final stream = Stream<int>.periodic(    const Duration(milliseconds: 200), (count) => count * count).take(4);await streamController.addStream(stream);

To send an error event to the stream, useaddError oraddStream.

streamController.addError(Exception('Issue 101'));await streamController.addStream(Stream.error(Exception('Issue 404')));

To check whether the stream is closed, useisClosed.

var isClosed = streamController.isClosed; // false

To close the stream, useclose.

await streamController.close();isClosed = streamController.isClosed; // true

Implemented types

• StreamSink<T>

Implementers

• MultiStreamController
• SynchronousStreamController

Constructors

StreamController({voidonListen()?,voidonPause()?,voidonResume()?,FutureOr<void>onCancel()?,boolsync =false})

A controller with astream that supports only one single subscriber.

factory

StreamController.broadcast({voidonListen()?,voidonCancel()?,boolsync =false})

A controller wherestream can be listened to more than once.

factory

Properties

done→Future

A future which is completed when the stream controller is donesending events.

no setteroverride

hashCode→int

The hash code for this object.

no setterinherited

hasListener→bool

Whether there is a subscriber on theStream.

no setter

isClosed→bool

Whether the stream controller is closed for adding more events.

no setter

isPaused→bool

Whether the subscription would need to buffer events.

no setter

onCancel↔FutureOr<void> Function()?

The callback which is called when the stream is canceled.

getter/setter pair

onListen↔ void Function()?

The callback which is called when the stream is listened to.

getter/setter pair

onPause↔ void Function()?

The callback which is called when the stream is paused.

getter/setter pair

onResume↔ void Function()?

The callback which is called when the stream is resumed.

getter/setter pair

runtimeType→Type

A representation of the runtime type of the object.

no setterinherited

sink→StreamSink<T>

Returns a view of this object that only exposes theStreamSink interface.

no setter

stream→Stream<T>

The stream that this controller is controlling.

no setter

Methods

add(Tevent)→ void

Sends a dataevent.

override

addError(Objecterror, [StackTrace?stackTrace])→ void

Sends or enqueues an error event.

override

addStream(Stream<T>source, {bool?cancelOnError})→Future

Receives events fromsource and puts them into this controller's stream.

override

close()→Future

Closes the stream.

override

noSuchMethod(Invocationinvocation)→ dynamic

Invoked when a nonexistent method or property is accessed.

inherited

toString()→String

A string representation of this object.

inherited

Operators

operator ==(Objectother)→bool

The equality operator.

inherited