public static interface EventChannel.StreamHandler
Implementations must be prepared to accept sequences of alternating calls to
#onListen(Object, EventSink)
and onCancel(Object)
. Implementations
should ideally consume no resources when the last such call is not onListen
.
In typical situations, this means that the implementation should register itself
with platform-specific event sources onListen
and deregister again
onCancel
.
Modifier and Type | Method and Description |
---|---|
void |
onCancel(Object arguments)
Handles a request to tear down the most recently created event stream.
|
void |
onListen(Object arguments,
EventChannel.EventSink events)
Handles a request to set up an event stream.
|
void onListen(Object arguments, EventChannel.EventSink events)
Any uncaught exception thrown by this method will be caught by the channel implementation and logged. An error result message will be sent back to Flutter.
arguments
- stream configuration arguments, possibly null.events
- an EventChannel.EventSink
for emitting events to the Flutter receiver.void onCancel(Object arguments)
Any uncaught exception thrown by this method will be caught by the channel implementation and logged. An error result message will be sent back to Flutter.
The channel implementation may call this method with null arguments to separate a pair of two consecutive set up requests. Such request pairs may occur during Flutter hot restart. Any uncaught exception thrown in this situation will be logged without notifying Flutter.
arguments
- stream configuration arguments, possibly null.