#鸿蒙通关秘籍#如何在异步线程中使用Node-API向ArkTS线程投递任务？

在异步线程中使用Node-API向ArkTS线程投递任务时，需要通过napi_call_threadsafe_function_with_priority接口实现。可以根据任务的优先级和入队方式来处理它们。

以下是关键步骤：

1. 创建并初始化结构体CallbackData以存储线程安全方法和异步工作的信息。
2. 编写CallJs函数提供ArkTS线程的回调实现，用于执行JS上下文中的任务。
3. 使用ExecuteWork函数在异步线程中调用napi_call_threadsafe_function_with_priority，并通过优先级和入队方式控制任务的处理顺序。
4. 在任务完成后，通过WorkComplete释放资源。
5. 在模块初始化中，将函数通过napi_define_properties注册到模块导出的接口。

完整代码如下： cpp #include "napi/native_api.h" #include <string.h> #include <stdlib.h>

struct CallbackData { napi_threadsafe_function tsfn; napi_async_work work; };

static void CallJs(napi_env env, napi_value jsCb, void *context, void *data) { if (env == nullptr) { return; } napi_value resultNumber = nullptr; napi_value undefined = nullptr; napi_get_undefined(env, &undefined); napi_value number1 = nullptr; napi_create_int32(env, 12, &number1); napi_value number2 = nullptr; napi_create_int32(env, 15, &number2); napi_value argv[2] = {number1, number2}; napi_call_function(env, undefined, jsCb, 2, argv, &resultNumber); int32_t res = 0; napi_get_value_int32(env, resultNumber, &res); }

static void ExecuteWork(napi_env env, void *data) { CallbackData *callbackData = reinterpret_cast<CallbackData *>(data); napi_call_threadsafe_function_with_priority(callbackData->tsfn, nullptr, napi_priority_idle, true); napi_call_threadsafe_function_with_priority(callbackData->tsfn, nullptr, napi_priority_low, true); napi_call_threadsafe_function_with_priority(callbackData->tsfn, nullptr, napi_priority_high, true); napi_call_threadsafe_function_with_priority(callbackData->tsfn, nullptr, napi_priority_immediate, true); napi_call_threadsafe_function_with_priority(callbackData->tsfn, nullptr, napi_priority_high, false); }

static void WorkComplete(napi_env env, napi_status status, void *data) { CallbackData *callbackData = reinterpret_cast<CallbackData *>(data); napi_release_threadsafe_function(callbackData->tsfn, napi_tsfn_release); napi_delete_async_work(env, callbackData->work); callbackData->work = nullptr; callbackData->tsfn = nullptr; }

static napi_value CallThreadSafeWithPriority(napi_env env, napi_callback_info info) { size_t argc = 1; napi_value jsCb = nullptr; CallbackData *callbackData = nullptr; napi_get_cb_info(env, info, &argc, &jsCb, nullptr, reinterpret_cast<void **>(&callbackData)); napi_value resourceName = nullptr; napi_create_string_utf8(env, "Thread-safe Function Demo", NAPI_AUTO_LENGTH, &resourceName); napi_create_threadsafe_function(env, jsCb, nullptr, resourceName, 0, 1, callbackData, nullptr, callbackData, CallJs, &callbackData->tsfn); napi_create_async_work(env, nullptr, resourceName, ExecuteWork, WorkComplete, callbackData, &callbackData->work); napi_queue_async_work(env, callbackData->work); return nullptr; }

EXTERN_C_START static napi_value Init(napi_env env, napi_value exports) { CallbackData *callbackData = new CallbackData(); napi_property_descriptor desc[] = { { "callThreadSafeWithPriority", nullptr, CallThreadSafeWithPriority, nullptr, nullptr, nullptr, napi_default, callbackData } }; napi_define_properties(env, exports, sizeof(desc) / sizeof(desc[0]), desc); return exports; } EXTERN_C_END

static napi_module nativeModule = { .nm_version = 1, .nm_flags = 0, .nm_filename = nullptr, .nm_register_func = Init, .nm_modname = "entry", .nm_priv = nullptr, .reserved = { 0 }, };

extern "C" attribute((constructor)) void RegisterEntryModule() { napi_module_register(&nativeModule); }