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flutter::MethodChannel< T > Class Template Reference

`#include <method_channel.h>`

## Public Member Functions
| MethodChannel (BinaryMessenger *messenger, const std::string &name, const MethodCodec< T > *codec)
| ~MethodChannel ()=default
| MethodChannel (MethodChannel const &)=delete
MethodChannel & | operator= (MethodChannel const &)=delete
void | InvokeMethod (const std::string &method, std::unique_ptr< T > arguments, std::unique_ptr< MethodResult< T >> result=nullptr)
void | SetMethodCallHandler (MethodCallHandler< T > handler) const
void | Resize (int new_size)
void | SetWarnsOnOverflow (bool warns)

## Detailed Description

### template<typename T = EncodableValue>
class flutter::MethodChannel< T >

Definition at line 34 of file method_channel.h.

## Constructor & Destructor Documentation

## ◆ MethodChannel() [1/2]

template<typename T = EncodableValue>

flutter::MethodChannel< T >::MethodChannel | ( | BinaryMessenger * | messenger,
|  | const std::string & | name,
|  | const MethodCodec< T > * | codec
| ) |  |
| inline

Definition at line 38 of file method_channel.h.

41 : messenger_(messenger), name_(name), codec_(codec) {}

## ◆ ~MethodChannel()

template<typename T = EncodableValue>

flutter::MethodChannel< T >::~MethodChannel | ( |  | ) |
| default

## ◆ MethodChannel() [2/2]

template<typename T = EncodableValue>

flutter::MethodChannel< T >::MethodChannel | ( | MethodChannel< T > const & |  | ) |
| delete

## Member Function Documentation

## ◆ InvokeMethod()

template<typename T = EncodableValue>

void flutter::MethodChannel< T >::InvokeMethod | ( | const std::string & | method,
|  | std::unique_ptr< T > | arguments,
|  | std::unique_ptr< MethodResult< T >> | result = `nullptr`
| ) |  |
| inline

Definition at line 53 of file method_channel.h.

55 {
56 MethodCall<T> method_call(method, std::move(arguments));
57 std::unique_ptr<std::vector<uint8_t>> message =
58 codec_->EncodeMethodCall(method_call);
59 if (!result) {
60 messenger_->Send(name_, message->data(), message->size(), nullptr);
61 return;
62 }
63
64 // std::function requires a copyable lambda, so convert to a shared pointer.
65 // This is safe since only one copy of the shared_pointer will ever be
66 // accessed.
67 std::shared_ptr<MethodResult<T>> shared_result(result.release());
68 const auto* codec = codec_;
69 std::string channel_name = name_;
70 BinaryReply reply_handler = [shared_result, codec, channel_name](
71 const uint8_t* reply, size_t reply_size) {
72 if (reply_size == 0) {
73 shared_result->NotImplemented();
74 return;
75 }
76 // Use this channel's codec to decode and handle the
77 // reply.
78 bool decoded = codec->DecodeAndProcessResponseEnvelope(
79 reply, reply_size, shared_result.get());
80 if (!decoded) {
81 std::cerr << "Unable to decode reply to method "
82 "invocation on channel "
83 << channel_name << std::endl;
84 shared_result->NotImplemented();
85 }
86 };
87
88 messenger_->Send(name_, message->data(), message->size(),
89 std::move(reply_handler));
90 }

References message, and flutter::BinaryMessenger::Send().

Referenced by flutter::TEST().

## ◆ operator=()

template<typename T = EncodableValue>

MethodChannel& flutter::MethodChannel< T >::operator= | ( | MethodChannel< T > const & |  | ) |
| delete

## ◆ Resize()

template<typename T = EncodableValue>

void flutter::MethodChannel< T >::Resize | ( | int | new_size | ) |
| inline

Definition at line 130 of file method_channel.h.

130 {
131 internal::ResizeChannel(messenger_, name_, new_size);
132 }

References flutter::internal::ResizeChannel().

Referenced by flutter::TEST().

## ◆ SetMethodCallHandler()

template<typename T = EncodableValue>

void flutter::MethodChannel< T >::SetMethodCallHandler | ( | MethodCallHandler< T > | handler | ) | const
| inline

Definition at line 99 of file method_channel.h.

99 {
100 if (!handler) {
101 messenger_->SetMessageHandler(name_, nullptr);
102 return;
103 }
104 const auto* codec = codec_;
105 std::string channel_name = name_;
106 BinaryMessageHandler binary_handler = [handler, codec, channel_name](
107 const uint8_t* message,
108 size_t message_size,
109 BinaryReply reply) {
110 // Use this channel's codec to decode the call and build a result handler.
111 auto result =
112 std::make_unique<EngineMethodResult<T>>(std::move(reply), codec);
113 std::unique_ptr<MethodCall<T>> method_call =
114 codec->DecodeMethodCall(message, message_size);
115 if (!method_call) {
116 std::cerr << "Unable to construct method call from message on channel "
117 << channel_name << std::endl;
118 result->NotImplemented();
119 return;
120 }
121 handler(*method_call, std::move(result));
122 };
123 messenger_->SetMessageHandler(name_, std::move(binary_handler));
124 }

References message, and flutter::BinaryMessenger::SetMessageHandler().

Referenced by flutter::TEST().

## ◆ SetWarnsOnOverflow()

template<typename T = EncodableValue>

void flutter::MethodChannel< T >::SetWarnsOnOverflow | ( | bool | warns | ) |
| inline

Definition at line 139 of file method_channel.h.

139 {
140 internal::SetChannelWarnsOnOverflow(messenger_, name_, warns);
141 }

References flutter::internal::SetChannelWarnsOnOverflow().

Referenced by flutter::TEST().

The documentation for this class was generated from the following file:

- shell/platform/common/client_wrapper/include/flutter/method_channel.h

flutter::BinaryMessenger::SetMessageHandler
virtual void SetMessageHandler(const std::string &channel, BinaryMessageHandler handler)=0
flutter::BinaryReply
std::function< void(const uint8_t *reply, size_t reply_size)> BinaryReply
Definition: binary_messenger.h:17
flutter::internal::ResizeChannel
void ResizeChannel(BinaryMessenger *messenger, std::string name, int new_size)
Definition: core_implementations.cc:181
flutter::internal::SetChannelWarnsOnOverflow
void SetChannelWarnsOnOverflow(BinaryMessenger *messenger, std::string name, bool warns)
Definition: core_implementations.cc:194
message
Win32Message message
Definition: keyboard_unittests.cc:137
flutter::BinaryMessenger::Send
virtual void Send(const std::string &channel, const uint8_t *message, size_t message_size, BinaryReply reply=nullptr) const =0
flutter::BinaryMessageHandler
std::function< void(const uint8_t *message, size_t message_size, BinaryReply reply)> BinaryMessageHandler
Definition: binary_messenger.h:24