FlutterMethodChannel

Objective-C

@interface FlutterMethodChannel : NSObject

Swift

class FlutterMethodChannel : NSObject

A channel for communicating with the Flutter side using invocation of asynchronous methods.

  • Creates a FlutterMethodChannel with the specified name and binary messenger.

    The channel name logically identifies the channel; identically named channels interfere with each other’s communication.

    The binary messenger is a facility for sending raw, binary messages to the Flutter side. This protocol is implemented by FlutterEngine and FlutterViewController.

    The channel uses FlutterStandardMethodCodec to encode and decode method calls and result envelopes.

    Declaration

    Objective-C

    + (nonnull instancetype)
    methodChannelWithName:(nonnull NSString *)name
          binaryMessenger:(nonnull NSObject<FlutterBinaryMessenger> *)messenger;

    Swift

    convenience init(name: String, binaryMessenger messenger: FlutterBinaryMessenger)

    Parameters

    name

    The channel name.
    messenger

    The binary messenger.

  • Creates a FlutterMethodChannel with the specified name, binary messenger, and method codec.

    The channel name logically identifies the channel; identically named channels interfere with each other’s communication.

    The binary messenger is a facility for sending raw, binary messages to the Flutter side. This protocol is implemented by FlutterEngine and FlutterViewController.

    Declaration

    Objective-C

    + (nonnull instancetype)
    methodChannelWithName:(nonnull NSString *)name
          binaryMessenger:(nonnull NSObject<FlutterBinaryMessenger> *)messenger
                    codec:(nonnull NSObject<FlutterMethodCodec> *)codec;

    Parameters

    name

    The channel name.
    messenger

    The binary messenger.
    codec

    The method codec.

  • Initializes a FlutterMethodChannel with the specified name, binary messenger, and method codec.

    The channel name logically identifies the channel; identically named channels interfere with each other’s communication.

    The binary messenger is a facility for sending raw, binary messages to the Flutter side. This protocol is implemented by FlutterEngine and FlutterViewController.

    Declaration

    Objective-C

    - (nonnull instancetype)
       initWithName:(nonnull NSString *)name
    binaryMessenger:(nonnull NSObject<FlutterBinaryMessenger> *)messenger
              codec:(nonnull NSObject<FlutterMethodCodec> *)codec;

    Swift

    init(name: String, binaryMessenger messenger: FlutterBinaryMessenger, codec: FlutterMethodCodec & NSObjectProtocol)

    Parameters

    name

    The channel name.
    messenger

    The binary messenger.
    codec

    The method codec.

  • Initializes a FlutterMethodChannel with the specified name, binary messenger, method codec, and task queue.

    The channel name logically identifies the channel; identically named channels interfere with each other’s communication.

    The binary messenger is a facility for sending raw, binary messages to the Flutter side. This protocol is implemented by FlutterEngine and FlutterViewController.

    Declaration

    Objective-C

    - (nonnull instancetype)
       initWithName:(nonnull NSString *)name
    binaryMessenger:(nonnull NSObject<FlutterBinaryMessenger> *)messenger
              codec:(nonnull NSObject<FlutterMethodCodec> *)codec
          taskQueue:(NSObject<FlutterTaskQueue> *_Nullable)taskQueue;

    Parameters

    name

    The channel name.
    messenger

    The binary messenger.
    codec

    The method codec.
    taskQueue

    The FlutterTaskQueue that executes the handler (see -[FlutterBinaryMessenger makeBackgroundTaskQueue]).

  • Invokes the specified Flutter method with the specified arguments, expecting no results.

    See

    MethodChannel.setMethodCallHandler

    Declaration

    Objective-C

    - (void)invokeMethod:(nonnull NSString *)method
           arguments:(id _Nullable)arguments;

    Swift

    func invokeMethod(_ method: String, arguments: Any?)

    Parameters

    method

    The name of the method to invoke.
    arguments

    The arguments. Must be a value supported by the codec of this channel.

  • Invokes the specified Flutter method with the specified arguments, expecting an asynchronous result.

    Declaration

    Objective-C

    - (void)invokeMethod:(nonnull NSString *)method
           arguments:(id _Nullable)arguments
              result:(FlutterResult _Nullable)callback;

    Swift

    func invokeMethod(_ method: String, arguments: Any?, result callback: FlutterResult? = nil)

    Parameters

    method

    The name of the method to invoke.
    arguments

    The arguments. Must be a value supported by the codec of this channel.
    callback

    A callback that will be invoked with the asynchronous result. The result will be a FlutterError instance, if the method call resulted in an error on the Flutter side. Will be FlutterMethodNotImplemented, if the method called was not implemented on the Flutter side. Any other value, including nil, should be interpreted as successful results.

  • Registers a handler for method calls from the Flutter side.

    Replaces any existing handler. Use a nil handler for unregistering the existing handler.

    Declaration

    Objective-C

    - (void)setMethodCallHandler:(FlutterMethodCallHandler _Nullable)handler;

    Swift

    func setMethodCallHandler(_ handler: FlutterMethodCallHandler?)

    Parameters

    handler

    The method call handler.

  • Adjusts the number of messages that will get buffered when sending messages to channels that aren’t fully set up yet. For example, the engine isn’t running yet or the channel’s message handler isn’t set up on the Dart side yet.

    Declaration

    Objective-C

    - (void)resizeChannelBuffer:(NSInteger)newSize;

    Swift

    func resizeBuffer(_ newSize: Int)