Package io.flutter.plugin.common

Interface BinaryMessenger

All Known Implementing Classes:

DartExecutor, FlutterNativeView, FlutterView

public interface BinaryMessenger

Facility for communicating with Flutter using asynchronous message passing with binary messages. The Flutter Dart code should use BinaryMessages to participate.

BinaryMessenger is expected to be utilized from a single thread throughout the duration of its existence. If created on the main thread, then all invocations should take place on the main thread. If created on a background thread, then all invocations should take place on that background thread.

See Also:

, which supports message passing with Strings and semi-structured messages., , which supports communication using asynchronous method invocation., , which supports communication using event streams.

Nested Class Summary

Nested Classes

Modifier and Type	Interface	Description
static interface	BinaryMessenger.BinaryMessageHandler	Handler for incoming binary messages from Flutter.
static interface	BinaryMessenger.BinaryReply	Binary message reply callback.
static interface	BinaryMessenger.TaskQueue	An abstraction over the threading policy used to invoke message handlers.

Method Summary

Modifier and Type	Method	Description
default BinaryMessenger.TaskQueue	makeBackgroundTaskQueue()	Creates a TaskQueue that executes the tasks serially on a background thread.
void	send(String channel, ByteBuffer message)	Sends a binary message to the Flutter application.
void	send(String channel, ByteBuffer message, BinaryMessenger.BinaryReply callback)	Sends a binary message to the Flutter application, optionally expecting a reply.
void	setMessageHandler(String channel, BinaryMessenger.BinaryMessageHandler handler)	Registers a handler to be invoked when the Flutter application sends a message to its host platform.
default void	setMessageHandler(String channel, BinaryMessenger.BinaryMessageHandler handler, BinaryMessenger.TaskQueue taskQueue)	Registers a handler to be invoked when the Flutter application sends a message to its host platform.

Method Detail

makeBackgroundTaskQueue

@UiThread
default BinaryMessenger.TaskQueue makeBackgroundTaskQueue()

Creates a TaskQueue that executes the tasks serially on a background thread.

There is no guarantee that the tasks will execute on the same thread, just that execution is serial.

send

@UiThread
void send(@NonNull
          String channel,
          @Nullable
          ByteBuffer message)

Sends a binary message to the Flutter application.

Parameters:

channel - the name String of the logical channel used for the message.

message - the message payload, a direct-allocated ByteBuffer with the message bytes between position zero and current position, or null.

send

@UiThread
void send(@NonNull
          String channel,
          @Nullable
          ByteBuffer message,
          @Nullable
          BinaryMessenger.BinaryReply callback)

Sends a binary message to the Flutter application, optionally expecting a reply.

Any uncaught exception thrown by the reply callback will be caught and logged.

Parameters:

channel - the name String of the logical channel used for the message.

message - the message payload, a direct-allocated ByteBuffer with the message bytes between position zero and current position, or null.

callback - a BinaryMessenger.BinaryReply callback invoked when the Flutter application responds to the message, possibly null.

setMessageHandler

@UiThread
void setMessageHandler(@NonNull
                       String channel,
                       @Nullable
                       BinaryMessenger.BinaryMessageHandler handler)

Registers a handler to be invoked when the Flutter application sends a message to its host platform.

Registration overwrites any previous registration for the same channel name. Use a null handler to deregister.

If no handler has been registered for a particular channel, any incoming message on that channel will be handled silently by sending a null reply.

Parameters:

channel - the name String of the channel.

handler - a BinaryMessenger.BinaryMessageHandler to be invoked on incoming messages, or null.

setMessageHandler

@UiThread
default void setMessageHandler(@NonNull
                               String channel,
                               @Nullable
                               BinaryMessenger.BinaryMessageHandler handler,
                               @Nullable
                               BinaryMessenger.TaskQueue taskQueue)

Registers a handler to be invoked when the Flutter application sends a message to its host platform.

Registration overwrites any previous registration for the same channel name. Use a null handler to deregister.

If no handler has been registered for a particular channel, any incoming message on that channel will be handled silently by sending a null reply.

Parameters:

channel - the name String of the channel.

handler - a BinaryMessenger.BinaryMessageHandler to be invoked on incoming messages, or null.

taskQueue - a BinaryMessenger.TaskQueue that specifies what thread will execute the handler. Specifying null means execute on the platform thread.