fl_event_channel.h File Reference

#include <gio/gio.h>
#include <glib-object.h>
#include <gmodule.h>
#include "fl_binary_messenger.h"
#include "fl_method_channel.h"
#include "fl_method_response.h"

Go to the source code of this file.

Functions
G_BEGIN_DECLS G_MODULE_EXPORT	G_DECLARE_FINAL_TYPE (FlEventChannel, fl_event_channel, FL, EVENT_CHANNEL, GObject) typedef FlMethodErrorResponse *(*FlEventChannelHandler)(FlEventChannel *channel
: a channel name.
fl_event_channel_new: @messenger: an #FlBinaryMessenger. @codec: the message codec. Creates an event channel. @codec must match the codec used on the Dart end of the channel. Returns: a new #FlEventChannel.
FlEventChannel *	fl_event_channel_new (FlBinaryMessenger *messenger, const gchar *name, FlMethodCodec *codec)
void	fl_event_channel_set_stream_handlers (FlEventChannel *channel, FlEventChannelHandler listen_handler, FlEventChannelHandler cancel_handler, gpointer user_data, GDestroyNotify destroy_notify)
gboolean	fl_event_channel_send (FlEventChannel *channel, FlValue *event, GCancellable *cancellable, GError **error)

Variables
G_BEGIN_DECLS G_MODULE_EXPORT FlValue *	args
G_BEGIN_DECLS G_MODULE_EXPORT FlValue gpointer	user_data

Function Documentation

fl_event_channel_new()

FlEventChannel * fl_event_channel_new	(	FlBinaryMessenger *	messenger,
		const gchar *	name,
		FlMethodCodec *	codec
	)

Definition at line 159 of file fl_event_channel.cc.

                          {
  g_return_val_if_fail(FL_IS_BINARY_MESSENGER(messenger), nullptr);
  g_return_val_if_fail(name != nullptr, nullptr);
  g_return_val_if_fail(FL_IS_METHOD_CODEC(codec), nullptr);
 
  FlEventChannel* self =
      FL_EVENT_CHANNEL(g_object_new(fl_event_channel_get_type(), nullptr));
 
  self->messenger = FL_BINARY_MESSENGER(g_object_ref(messenger));
  self->name = g_strdup(name);
  self->codec = FL_METHOD_CODEC(g_object_ref(codec));
 
  fl_binary_messenger_set_message_handler_on_channel(
      self->messenger, self->name, message_cb, g_object_ref(self),
      channel_closed_cb);
 
  return self;
}

fl_event_channel_send()

gboolean fl_event_channel_send	(	FlEventChannel *	channel,
		FlValue *	event,
		GCancellable *	cancellable,
		GError **	error
	)

fl_event_channel_send: @channel: an #FlEventChannel. @event: event to send, must match what the #FlMethodCodec supports. @cancellable: (allow-none): a #GCancellable or NULL. @error: (allow-none): #GError location to store the error occurring, or NULL to ignore.

Sends an event on the channel. Events should only be sent once the channel is being listened to.

Returns: TRUE if successful.

Definition at line 196 of file fl_event_channel.cc.

                                                               {
  g_return_val_if_fail(FL_IS_EVENT_CHANNEL(self), FALSE);
  g_return_val_if_fail(event != nullptr, FALSE);
 
  g_autoptr(GBytes) data =
      fl_method_codec_encode_success_envelope(self->codec, event, error);
  if (data == nullptr) {
    return FALSE;
  }
 
  fl_binary_messenger_send_on_channel(self->messenger, self->name, data,
                                      cancellable, nullptr, nullptr);
 
  return TRUE;
}

fl_event_channel_set_stream_handlers()

void fl_event_channel_set_stream_handlers	(	FlEventChannel *	channel,
		FlEventChannelHandler	listen_handler,
		FlEventChannelHandler	cancel_handler,
		gpointer	user_data,
		GDestroyNotify	destroy_notify
	)

fl_event_channel_set_stream_handlers: @channel: an #FlEventChannel. @listen_handler: (allow-none): function to call when the Dart side of the channel starts listening to the stream. @cancel_handler: (allow-none): function to call when the Dart side of the channel cancels their subscription to the stream. @user_data: (closure): user data to pass to @listen_handler and @cancel_handler. @destroy_notify: (allow-none): a function which gets called to free @user_data, or NULL.

Sets the functions called when the Dart side requests the stream to start and finish.

The handlers are removed if the channel is closed or is replaced by another handler, set @destroy_notify if you want to detect this.

Definition at line 181 of file fl_event_channel.cc.

                                   {
  g_return_if_fail(FL_IS_EVENT_CHANNEL(self));
 
  remove_handlers(self);
  self->listen_handler = listen_handler;
  self->cancel_handler = cancel_handler;
  self->handler_data = user_data;
  self->handler_data_destroy_notify = destroy_notify;
}

G_DECLARE_FINAL_TYPE()

G_BEGIN_DECLS G_MODULE_EXPORT G_DECLARE_FINAL_TYPE	(	FlEventChannel	,
		fl_event_channel	,
		FL	,
		EVENT_CHANNEL	,
		GObject
	)

FlEventChannel:

#FlEventChannel is an object that allows sending an events stream to Dart code over platform channels.

The following example shows how to send events on a channel:

|[ static FlEventChannel *channel = NULL; static gboolean send_events = FALSE;

static void event_occurs_cb (FooEvent *event) { if (send_events) { g_autoptr(FlValue) message = foo_event_to_value (event); g_autoptr(GError) error = NULL; if (!fl_event_channel_send (channel, message, NULL, &error)) { g_warning ("Failed to send event: %s", error->message); } } }

static FlMethodErrorResponse* listen_cb (FlEventChannel* channel, FlValue *args, gpointer user_data) { send_events = TRUE; return NULL; }

static FlMethodErrorResponse* cancel_cb (GObject *object, FlValue *args, gpointer user_data) { send_events = FALSE; return NULL; }

static void setup_channel () { g_autoptr(FlStandardMethodCodec) codec = fl_standard_method_codec_new (); channel = fl_event_channel_new (messenger, "flutter/foo", FL_METHOD_CODEC (codec)); fl_event_channel_set_stream_handlers (channel, listen_cb, cancel_cb, NULL, NULL); } ]|

#FlEventChannel matches the EventChannel class in the Flutter services library. FlEventChannelHandler: @channel: an #FlEventChannel. @args: arguments passed from the Dart end of the channel. @user_data: (closure): data provided when registering this handler.

Function called when the stream is listened to or cancelled.

Returns: (transfer full): an #FlMethodErrorResponse or NULL if no error.

Variable Documentation

args

G_BEGIN_DECLS G_MODULE_EXPORT FlValue* args

Definition at line 89 of file fl_event_channel.h.

user_data

G_BEGIN_DECLS G_MODULE_EXPORT FlValue gpointer user_data

Definition at line 90 of file fl_event_channel.h.