用Rust开发鸿蒙应用（ArkTS NAPI）

开发流程

在DevEco Studio的模板工程中包含使用Native API的默认工程，使用File->New->Create Project创建Native C++模板工程。

在此基础上进行修改

删除

entry/src/main/cpp

打开

entry/build-profile.json5

删除c++ build 配置

{
  "apiType": "stageMode",
  "buildOption": {
    // "externalNativeOptions": {
    //  "path": "./src/main/rust/CMakeLists.txt",
    //  "arguments": "",
    //  "cppFlags": "",
    //  }
  },
  "targets": [
    {
      "name": "default",
      "runtimeOS": "HarmonyOS"
    },
    {
      "name": "ohosTest",
    }
  ]
}

创建rust项目

cargo new hello

修改 Cargo.toml

[package]
name = "hello"
version = "0.1.0"
edition = "2021"

[lib]
name = "hello"
crate-type = ["dylib"]

[dependencies]
oh-napi-sys = "0.1" 
ctor = "0.1"

lib.rs 添加测试代码

usestd::ffi::{CString};usestd::ptr::{null_mut};useoh_napi_sys::*;usector::ctor;extern"C"fnadd(env: napi_env, info: napi_callback_info)->napi_value{// 期望从ArkTS侧获取的参数的数量，napi_value可理解为ArkTS value在Native方法中的表现形式。letmut args:[napi_value;2]=[null_mut();2];letmut argc = args.len();unsafe{napi_get_cb_info(env, info,&mut argc, args.as_mut_ptr(),null_mut(),null_mut());letmut valuetype0  = napi_valuetype_napi_undefined;napi_typeof(env, args[0],&mut valuetype0);letmut valuetype1  = napi_valuetype_napi_undefined;napi_typeof(env, args[1],&mut valuetype1);if(valuetype0 != napi_valuetype_napi_number)||(valuetype1 != napi_valuetype_napi_number){letmut undefined: napi_value=null_mut();napi_get_undefined(env,&mut undefined);return undefined;}// 将获取的ArkTS参数转换为Native信息，此处ArkTS侧传入了两个number，这里将其转换为Native侧可以操作的double类型。letmut value0 =0f64;napi_get_value_double(env, args[0],&mut value0);letmut value1 =0f64;napi_get_value_double(env, args[1],&mut value1);// Native侧的业务逻辑，这里简单以两数相加为例。let native_sum = value0 + value1;// 此处将Native侧业务逻辑处理结果转换为ArkTS值，并返回给ArkTS。letmut sum =null_mut();napi_create_double(env, native_sum,&mut sum);return sum;}}typeCallback=extern"C"fn(env: napi_env, info: napi_callback_info)-> napi_value;unsafefnnew_func_descriptor(name:&'staticstr, f:Callback)->napi_property_descriptor{let name=CString::new(name).unwrap();
    napi_property_descriptor{
        utf8name:CString::into_raw(name),
        name:null_mut(),
        method:Some(f),
        getter:None,
        setter:None,
        value:null_mut(),
        attributes: napi_property_attributes_napi_default,
        data:null_mut(),}}// 注册 module#[ctor]fnregister_hello_module(){let name=CString::new("hello").unwrap();letmut hello_module = napi_module{
        nm_version:1,
        nm_flags:0,
        nm_filename:null_mut(),
        nm_register_func:Some(init),
        nm_modname: name.as_ptr()as _,
        nm_priv:0as*mut _,
        reserved:[0as*mut _;4],};unsafe{napi_module_register(&mut hello_module);}// Init将在exports上挂上Add/NativeCallArkTS这些Native方法，此处的exports就是开发者import之后获取到的ArkTS对象。unsafeextern"C"fninit(env: napi_env , exports: napi_value )-> napi_value {let desc =[new_func_descriptor("add", add),];let count = desc.len();napi_define_properties(env, exports, count, desc.as_ptr());return exports;}}

添加对应ts代码

// entry/src/main/rust/types/libhello/index.d.tsexportconstadd:(a:number, b:number)=>number;

// entry/src/main/rust/types/libhello/oh-package.json5{"name":"libhello.so","types":"./index.d.ts","version":"","description":"Please describe the basic information."}

配置依赖

// entry/oh-package.json5{"name":"entry","version":"1.0.0","description":"Please describe the basic information.","main":"","author":"","license":"","dependencies":{"libhello.so":"file:./src/main/rust/types/libhello"}}

在 rust 根目录下编译，添加ohos目标的教程可以参考 Rust交叉编译OpenHarmony应用动态库

cargo build -Zbuild-std  --release--target aarch64-unknown-linux-ohos

将编译好的

libhello.so

拷贝至

entry/libs/arm64-v8a

修改页面

Index.ets

import testNapi from'libhello.so'// onClick 里添加
hilog.info(0x0000,'testTag','Test NAPI 2 + 3 = %{public}d', testNapi.add(2,3));

编译app点击

hello world

，日志中看到

Test NAPI 2 + 3 = 5