鸿蒙HarmonyOS应用开发之Native与ArkTS对象绑定

场景介绍

通过napi_wrap将ArkTS对象与Native的C++对象绑定，后续操作时再通过napi_unwrap将ArkTS对象绑定的C++对象取出，并对其进行操作。

使用示例

接口声明、编译配置以及模块注册

接口声明

// index.d.ts
export class MyObject {constructor(arg: number);plusOne: () => number;public get value();public set value(newVal: number);
}

编译配置

// CMakeLists.txt
# the minimum version of CMake.
cmake_minimum_required(VERSION 3.4.1)
project(object_wrap)set(NATIVERENDER_ROOT_PATH ${CMAKE_CURRENT_SOURCE_DIR})include_directories(${NATIVERENDER_ROOT_PATH}${NATIVERENDER_ROOT_PATH}/include)add_definitions("-DLOG_DOMAIN=0x0000")
add_definitions("-DLOG_TAG=\"testTag\"")add_library(object_wrap SHARED object_wrap.cpp)
target_link_libraries(object_wrap PUBLIC libace_napi.z.so libhilog_ndk.z.so)

模块注册

// object_wrap.cpp
class MyObject {public:static napi_value Init(napi_env env, napi_value exports);static void Destructor(napi_env env, void* nativeObject, void* finalize_hint);private:explicit MyObject(double value_ = 0);~MyObject();static napi_value New(napi_env env, napi_callback_info info);static napi_value GetValue(napi_env env, napi_callback_info info);static napi_value SetValue(napi_env env, napi_callback_info info);static napi_value PlusOne(napi_env env, napi_callback_info info);double value_;napi_env env_;napi_ref wrapper_;
};static thread_local napi_ref g_ref = nullptr;MyObject::MyObject(double value): value_(value), env_(nullptr), wrapper_(nullptr) {}MyObject::~MyObject()
{napi_delete_reference(env_, wrapper_);
}void MyObject::Destructor(napi_env env,void* nativeObject,[[maybe_unused]] void* finalize_hint)
{OH_LOG_INFO(LOG_APP, "MyObject::Destructor called");reinterpret_cast<MyObject*>(nativeObject)->~MyObject();
}napi_value MyObject::Init(napi_env env, napi_value exports)
{napi_property_descriptor properties[] = {{"value", 0, 0, GetValue, SetValue, 0, napi_default, 0},{ "plusOne", nullptr, PlusOne, nullptr, nullptr, nullptr, napi_default, nullptr }};napi_value cons;assert(napi_define_class(env, "MyObject", NAPI_AUTO_LENGTH, New, nullptr, 2,properties, &cons) == napi_ok);assert(napi_create_reference(env, cons, 1, &g_ref) == napi_ok);assert(napi_set_named_property(env, exports, "MyObject", cons) == napi_ok);return exports;
}EXTERN_C_START
static napi_value Init(napi_env env, napi_value exports)
{MyObject::Init(env, exports);return exports;
}
EXTERN_C_ENDstatic napi_module nativeModule = {.nm_version = 1,.nm_flags = 0,.nm_filename = nullptr,.nm_register_func = Init,.nm_modname = "object_wrap",.nm_priv = nullptr,.reserved = { 0 },
};extern "C" __attribute__((constructor)) void RegisterObjectWrapModule()
{napi_module_register(&nativeModule);
}

在构造函数中绑定ArkJS与C++对象

napi_value MyObject::New(napi_env env, napi_callback_info info)
{OH_LOG_INFO(LOG_APP, "MyObject::New called");napi_value newTarget;assert(napi_get_new_target(env, info, &newTarget) == napi_ok);if (newTarget != nullptr) {// 使用`new MyObject(...)`调用方式size_t argc = 1;napi_value args[1];napi_value jsThis;assert(napi_get_cb_info(env, info, &argc, args, &jsThis, nullptr) == napi_ok);double value = 0.0;napi_valuetype valuetype;assert(napi_typeof(env, args[0], &valuetype) == napi_ok);if (valuetype != napi_undefined) {assert(napi_get_value_double(env, args[0], &value) == napi_ok);}MyObject* obj = new MyObject(value);obj->env_ = env;// 通过napi_wrap将ArkTS对象jsThis与C++对象obj绑定assert(napi_wrap(env,jsThis,reinterpret_cast<void*>(obj),MyObject::Destructor,nullptr,  // finalize_hint&obj->wrapper_) == napi_ok);return jsThis;} else {// 使用`MyObject(...)`调用方式size_t argc = 1;napi_value args[1];assert(napi_get_cb_info(env, info, &argc, args, nullptr, nullptr) == napi_ok && argc == 1);napi_value cons;assert(napi_get_reference_value(env, g_ref, &cons) == napi_ok);napi_value instance;assert(napi_new_instance(env, cons, argc, args, &instance) == napi_ok);return instance;}
}

将ArkTS对象之前绑定的C++对象取出，并对其进行操作

napi_value MyObject::GetValue(napi_env env, napi_callback_info info)
{OH_LOG_INFO(LOG_APP, "MyObject::GetValue called");napi_value jsThis;assert(napi_get_cb_info(env, info, nullptr, nullptr, &jsThis, nullptr) == napi_ok);MyObject* obj;// 通过napi_unwrap将jsThis之前绑定的C++对象取出，并对其进行操作assert(napi_unwrap(env, jsThis, reinterpret_cast<void**>(&obj)) == napi_ok);napi_value num;assert(napi_create_double(env, obj->value_, &num) == napi_ok);return num;
}napi_value MyObject::SetValue(napi_env env, napi_callback_info info)
{OH_LOG_INFO(LOG_APP, "MyObject::SetValue called");size_t argc = 1;napi_value value;napi_value jsThis;assert(napi_get_cb_info(env, info, &argc, &value, &jsThis, nullptr) == napi_ok);MyObject* obj;// 通过napi_unwrap将jsThis之前绑定的C++对象取出，并对其进行操作assert(napi_unwrap(env, jsThis, reinterpret_cast<void**>(&obj)) == napi_ok);assert(napi_get_value_double(env, value, &obj->value_) == napi_ok);return nullptr;
}napi_value MyObject::PlusOne(napi_env env, napi_callback_info info)
{OH_LOG_INFO(LOG_APP, "MyObject::PlusOne called");napi_value jsThis;assert(napi_get_cb_info(env, info, nullptr, nullptr, &jsThis, nullptr) == napi_ok);MyObject* obj;// 通过napi_unwrap将jsThis之前绑定的C++对象取出，并对其进行操作assert(napi_unwrap(env, jsThis, reinterpret_cast<void**>(&obj)) == napi_ok);obj->value_ += 1;napi_value num;assert(napi_create_double(env, obj->value_, &num) == napi_ok);return num;
}

ArkTS侧示例代码

import hilog from '@ohos.hilog';
import { MyObject } from 'libobject_wrap.so'let object : MyObject = new MyObject(0);
object.value = 1023;
hilog.info(0x0000, 'testTag', 'MyObject value after set: %{public}d', object.value);
hilog.info(0x0000, 'testTag', 'MyObject plusOne: %{public}d', object.plusOne());

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