HarmonyOS 关于NAPI开发C层实现异步化回调问题

目前常规的NAPI调用示例为同步方法调用，例如：

napi_value MyObject::GetValue(napi_env env, napi_callback_info info) 
{ 
  napi_status status; 
 
  napi_value jsthis; 
  ...... 
  status = napi_create_double(env, obj->value_, &num); 
  assert(status == napi_ok); 
 
  return num; 
}1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.

对于一种场景，ts层调用native的方法A，A进入C层进行异步化（线程池调用）后需要回调ts层设置的callback方法这种场景下，本地利用napi的示例代码未找到比较好的实现方案。该场景能否提供一套napi层在子线程回调ts层callback的示例代码

HarmonyOS

superinsect

2024-08-22 23:19:26

1123浏览

回答 1

按赞同

按时间

zbw_apple

void NAPITakePhotoManger::Js_Takephoto_Code_Callback( 
  napi_env env, napi_ref callbackRef, uint32_t code) 
{ 
    CFWK_HILOGI(CALLBACK, "enter"); 
    if (callbackRef == nullptr) { 
        CFWK_HILOGE(CALLBACK, "callbackRef IS NULL"); 
        return; 
    } 
    CameraAbilityEventContext* asyncContext = new (std::nothrow) CameraAbilityEventContext(); 
    uv_work_t* work = new (std::nothrow) uv_work_t; 
    uv_loop_s* loop = nullptr; 
    napi_get_uv_event_loop(env, &loop); 
    if (asyncContext == nullptr || work == nullptr || loop == nullptr) { 
        delete asyncContext; 
        delete work; 
        CFWK_HILOGE(CALLBACK, "asyncContext is null or work is null"); 
        return; 
    } 
    asyncContext->env = env; 
    asyncContext->jsCallback = callbackRef; 
    asyncContext->code = code; 
    work->data = (void *)asyncContext; 
 
    int32_t res = uv_queue_work(loop, work, [](uv_work_t* work) {}, [](uv_work_t* work, int status) { 
        CameraAbilityEventContext* context = (CameraAbilityEventContext*)work->data; 
        napi_handle_scope scope = nullptr; 
        napi_open_handle_scope(context->env, &scope); 
        if (scope == nullptr) { 
            delete context; 
            delete work; 
            return; 
        } 
        napi_value callBack = nullptr; 
        napi_get_reference_value(context->env, context->jsCallback, &callBack); 
        if (callBack == nullptr) { 
            CFWK_HILOGE(CALLBACK, "callBack IS NULL"); 
            delete context; 
            delete work; 
            return; 
        } 
        napi_value resultObj = nullptr; 
        napi_create_object(context->env, &resultObj); 
        napi_value code; 
        napi_create_uint32(context->env, context->code, &code); 
        CFWK_HILOGI(CALLBACK, "code =%{public}d", context->code); 
        napi_create_string_utf8(context->env, context->event.c_str(), NAPI_AUTO_LENGTH, &category_); 
        napi_set_named_property(context->env, resultObj, "code", code); 
        napi_set_named_property(context->env, resultObj, "name", "张三"); 
        napi_value ret; 
void NAPITakePhotoManger::Js_Code_Callback( 
    napi_env env, napi_ref callbackRef, uint32_t code) 
{ 
    CFWK_HILOGI(CALLBACK, "enter"); 
    if (callbackRef == nullptr) { 
        CFWK_HILOGE(CALLBACK, "callbackRef IS NULL"); 
        return; 
    } 
    CameraAbilityEventContext* asyncContext = new (std::nothrow) CameraAbilityEventContext(); 
    uv_work_t* work = new (std::nothrow) uv_work_t; 
    uv_loop_s* loop = nullptr; 
    napi_get_uv_event_loop(env, &loop); 
    if (asyncContext == nullptr || work == nullptr || loop == nullptr) { 
        delete asyncContext; 
        delete work; 
        CFWK_HILOGE(CALLBACK, "asyncContext is null or work is null"); 
        return; 
    } 
    asyncContext->env = env; 
    asyncContext->jsCallback = callbackRef; 
    asyncContext->code = code; 
    work->data = (void *)asyncContext; 
 
    int32_t res = uv_queue_work(loop, work, [](uv_work_t* work) {}, [](uv_work_t* work, int status) { 
        CameraAbilityEventContext* context = (CameraAbilityEventContext*)work->data; 
        napi_handle_scope scope = nullptr; 
        napi_open_handle_scope(context->env, &scope); 
        if (scope == nullptr) { 
            delete context; 
            delete work; 
            return; 
        } 
        napi_value callBack = nullptr; 
        napi_get_reference_value(context->env, context->jsCallback, &callBack); 
        if (callBack == nullptr) { 
            CFWK_HILOGE(CALLBACK, "callBack IS NULL"); 
            delete context; 
            delete work; 
            return; 
        } 
        napi_value resultObj = nullptr; 
        napi_create_object(context->env, &resultObj); 
        napi_value code; 
        napi_create_uint32(context->env, context->code, &code); 
        CFWK_HILOGI(CALLBACK, "code =%{public}d", context->code); 
        napi_create_string_utf8(context->env, context->event.c_str(), NAPI_AUTO_LENGTH, &category_); 
        napi_set_named_property(context->env, resultObj, "code", code); 
        napi_set_named_property(context->env, resultObj, "name", "张三"); 
        napi_value ret; 
napi_call_function(context->env, nullptr, callBack, 1, &resultObj, &ret); 
        if (context->code == 0) { 
            napi_delete_reference(context->env, context->jsCallback); 
        } 
        napi_close_handle_scope(context->env, scope); 
        delete context; 
        delete work; 
    }); 
    if (res != RES_SUCCESS) { 
        CFWK_HILOGE(CALLBACK, "add uv queue fail"); 
        delete (CameraAbilityEventContext*)work->data; 
        delete work; 
    } 
    CFWK_HILOGI(CALLBACK, "leave"); 
}1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
15.
16.
17.
18.
19.
20.
21.
22.
23.
24.
25.
26.
27.
28.
29.
30.
31.
32.
33.
34.
35.
36.
37.
38.
39.
40.
41.
42.
43.
44.
45.
46.
47.
48.
49.
50.
51.
52.
53.
54.
55.
56.
57.
58.
59.
60.
61.
62.
63.
64.
65.
66.
67.
68.
69.
70.
71.
72.
73.
74.
75.
76.
77.
78.
79.
80.
81.
82.
83.
84.
85.
86.
87.
88.
89.
90.
91.
92.
93.
94.
95.
96.
97.
98.
99.
100.
101.
102.
103.
104.
105.
106.
107.
108.
109.
110.
111.
112.
113.

2024-08-23 16:25:44

如何写精华回答，获更多曝光？

发布

51CTO

51CTO博客

51CTO学堂

HarmonyOS 关于NAPI开发C层实现异步化回调问题

订阅鸿蒙技术特刊，精选内容抢先看