1# Native与ArkTS对象绑定
2
3## 场景介绍
4
5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。
6
7## 使用示例
8
91. 接口声明、编译配置以及模块注册
10
11   **接口声明**
12
13   ```ts
14   // index.d.ts
15   export class MyObject {
16      constructor(arg: number);
17      plusOne: () => number;
18   
19      public get value();
20      public set value(newVal: number);
21   }
22   ```
23
24   **编译配置**
25
26   ```
27   # the minimum version of CMake.
28   cmake_minimum_required(VERSION 3.5.0)
29   project(napi_wrap_demo)
30
31   set(NATIVERENDER_ROOT_PATH ${CMAKE_CURRENT_SOURCE_DIR})
32
33   if(DEFINED PACKAGE_FIND_FILE)
34       include(${PACKAGE_FIND_FILE})
35   endif()
36
37   include_directories(${NATIVERENDER_ROOT_PATH}
38                       ${NATIVERENDER_ROOT_PATH}/include)
39
40   add_definitions("-DLOG_DOMAIN=0x0000")
41   add_definitions("-DLOG_TAG=\"testTag\"")
42
43   add_library(entry SHARED napi_init.cpp)
44   target_link_libraries(entry PUBLIC libace_napi.z.so libhilog_ndk.z.so)
45   ```
46
47   **模块注册**
48
49   ```cpp
50   // napi_init.cpp
51   #include "napi/native_api.h"
52   #include "hilog/log.h"
53
54   class MyObject {
55    public:
56     static napi_value Init(napi_env env, napi_value exports);
57     static void Destructor(napi_env env, void* nativeObject, void* finalize_hint);
58   
59    private:
60     explicit MyObject(double value_ = 0);
61     ~MyObject();
62   
63     static napi_value New(napi_env env, napi_callback_info info);
64     static napi_value GetValue(napi_env env, napi_callback_info info);
65     static napi_value SetValue(napi_env env, napi_callback_info info);
66     static napi_value PlusOne(napi_env env, napi_callback_info info);
67   
68     double value_;
69     napi_env env_;
70     napi_ref wrapper_;
71   };
72   
73   static thread_local napi_ref g_ref = nullptr;
74   
75   MyObject::MyObject(double value)
76       : value_(value), env_(nullptr), wrapper_(nullptr) {}
77   
78   MyObject::~MyObject()
79   {
80     napi_delete_reference(env_, wrapper_);
81   }
82   
83   void MyObject::Destructor(napi_env env,
84                             void* nativeObject,
85                             [[maybe_unused]] void* finalize_hint)
86   {
87     OH_LOG_INFO(LOG_APP, "MyObject::Destructor called");
88     reinterpret_cast<MyObject*>(nativeObject)->~MyObject();
89   }
90   
91   napi_value MyObject::Init(napi_env env, napi_value exports)
92   {
93     napi_property_descriptor properties[] = {
94         { "value", 0, 0, GetValue, SetValue, 0, napi_default, 0 },
95         { "plusOne", nullptr, PlusOne, nullptr, nullptr, nullptr, napi_default, nullptr }
96     };
97   
98     napi_value cons;
99     napi_define_class(env, "MyObject", NAPI_AUTO_LENGTH, New, nullptr, 2,
100                              properties, &cons);
101   
102     napi_create_reference(env, cons, 1, &g_ref);
103     napi_set_named_property(env, exports, "MyObject", cons);
104     return exports;
105   }
106   
107   EXTERN_C_START
108   static napi_value Init(napi_env env, napi_value exports)
109   {
110       MyObject::Init(env, exports);
111       return exports;
112   }
113   EXTERN_C_END
114   
115   static napi_module nativeModule = {
116       .nm_version = 1,
117       .nm_flags = 0,
118       .nm_filename = nullptr,
119       .nm_register_func = Init,
120       .nm_modname = "entry",
121       .nm_priv = nullptr,
122       .reserved = { 0 },
123   };
124   
125   extern "C" __attribute__((constructor)) void RegisterObjectWrapModule()
126   {
127       napi_module_register(&nativeModule);
128   }
129   ```
130
1312. 在构造函数中绑定ArkJS与C++对象
132
133   ```cpp
134   napi_value MyObject::New(napi_env env, napi_callback_info info)
135   {
136     OH_LOG_INFO(LOG_APP, "MyObject::New called");
137   
138     napi_value newTarget;
139     napi_get_new_target(env, info, &newTarget);
140     if (newTarget != nullptr) {
141       // 使用`new MyObject(...)`调用方式
142       size_t argc = 1;
143       napi_value args[1];
144       napi_value jsThis;
145       napi_get_cb_info(env, info, &argc, args, &jsThis, nullptr);
146   
147       double value = 0.0;
148       napi_valuetype valuetype;
149       napi_typeof(env, args[0], &valuetype);
150       if (valuetype != napi_undefined) {
151         napi_get_value_double(env, args[0], &value);
152       }
153   
154       MyObject* obj = new MyObject(value);
155   
156       obj->env_ = env;
157       // 通过napi_wrap将ArkTS对象jsThis与C++对象obj绑定
158       napi_wrap(env,
159                 jsThis,
160                 reinterpret_cast<void*>(obj),
161                 MyObject::Destructor,
162                 nullptr,  // finalize_hint
163                 &obj->wrapper_);
164   
165       return jsThis;
166     } else {
167       // 使用`MyObject(...)`调用方式
168       size_t argc = 1;
169       napi_value args[1];
170       napi_get_cb_info(env, info, &argc, args, nullptr, nullptr);
171   
172       napi_value cons;
173       napi_get_reference_value(env, g_ref, &cons);
174       napi_value instance;
175       napi_new_instance(env, cons, argc, args, &instance);
176   
177       return instance;
178     }
179   }
180   ```
181
1823. 将ArkTS对象之前绑定的C++对象取出，并对其进行操作
183
184   ```cpp
185   napi_value MyObject::GetValue(napi_env env, napi_callback_info info)
186   {
187     OH_LOG_INFO(LOG_APP, "MyObject::GetValue called");
188   
189     napi_value jsThis;
190     napi_get_cb_info(env, info, nullptr, nullptr, &jsThis, nullptr);
191   
192     MyObject* obj;
193     // 通过napi_unwrap将jsThis之前绑定的C++对象取出，并对其进行操作
194     napi_unwrap(env, jsThis, reinterpret_cast<void**>(&obj));
195     napi_value num;
196     napi_create_double(env, obj->value_, &num);
197   
198     return num;
199   }
200   
201   napi_value MyObject::SetValue(napi_env env, napi_callback_info info)
202   {
203     OH_LOG_INFO(LOG_APP, "MyObject::SetValue called");
204   
205     size_t argc = 1;
206     napi_value value;
207     napi_value jsThis;
208   
209     napi_get_cb_info(env, info, &argc, &value, &jsThis, nullptr);
210   
211     MyObject* obj;
212     // 通过napi_unwrap将jsThis之前绑定的C++对象取出，并对其进行操作
213     napi_unwrap(env, jsThis, reinterpret_cast<void**>(&obj));
214     napi_get_value_double(env, value, &obj->value_);
215   
216     return nullptr;
217   }
218   
219   napi_value MyObject::PlusOne(napi_env env, napi_callback_info info)
220   {
221     OH_LOG_INFO(LOG_APP, "MyObject::PlusOne called");
222   
223     napi_value jsThis;
224     napi_get_cb_info(env, info, nullptr, nullptr, &jsThis, nullptr);
225   
226     MyObject* obj;
227     // 通过napi_unwrap将jsThis之前绑定的C++对象取出，并对其进行操作
228     napi_unwrap(env, jsThis, reinterpret_cast<void**>(&obj));
229     obj->value_ += 1;
230     napi_value num;
231     napi_create_double(env, obj->value_, &num);
232   
233     return num;
234   }
235   ```
236
2374. ArkTS侧示例代码 
238
239   ```ts
240   import hilog from '@ohos.hilog';
241   import { MyObject } from 'libentry.so';
242   
243   let object : MyObject = new MyObject(0);
244   object.value = 1023;
245   hilog.info(0x0000, 'testTag', 'MyObject value after set: %{public}d', object.value);
246   hilog.info(0x0000, 'testTag', 'MyObject plusOne: %{public}d', object.plusOne());
247   ```
248