Interface EventChannel.StreamHandler
- Enclosing class:
- EventChannel
Implementations must be prepared to accept sequences of alternating calls to onListen(Object, EventChannel.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
.
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Method Summary
Modifier and TypeMethodDescriptionvoid
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.
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Method Details
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onListen
Handles a request to set up an event stream.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.
- Parameters:
arguments
- stream configuration arguments, possibly null.events
- anEventChannel.EventSink
for emitting events to the Flutter receiver.
-
onCancel
Handles a request to tear down the most recently created event stream.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.
- Parameters:
arguments
- stream configuration arguments, possibly null.
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