临沂做网站的,做相册的网站（网易,大学生就业信息招聘网,甘肃最新消息今天OpenHarmony的NAPI功能为开发者提供了JS与C/C不同语言模块之间的相互访问#xff0c;交互的能力#xff0c;使得开发者使用C或者C语言实现应用的关键功能。如操作开发板中某个GPIO节点的状态#xff08;OpenHarmony并没有提供直接操作GPIO口状态的API#xff09;#xff0… OpenHarmony的NAPI功能为开发者提供了JS与C/C不同语言模块之间的相互访问交互的能力使得开发者使用C或者C语言实现应用的关键功能。如操作开发板中某个GPIO节点的状态OpenHarmony并没有提供直接操作GPIO口状态的API点亮一个LED灯。 本篇基于前3篇NAPI的讲解总结做一个控制开发板上LED灯状态的应用作为完结篇。
一、环境准备 设备rk3568开发板 开发环境DevEco Studio4.0.0.600
二、NAPI函数编写 1、基于NAPI的GPIO节点控制函数 OpenHarmony并没有提供直接操作GPIO口状态的API。若需要控制开发板上LED灯的亮灭 需要通过NAPI的方式写一个可以查询GPIO口状态、一个可以对节点写1和一个可以对节点写0的函数。
1main目录如下 2bq_function.cpp
#include napi/native_api.h
#include napi/native_api.h
#include cstring
#include js_native_api.h
#include sys/un.h
#include unistd.h
#include sys/types.h
#include fcntl.h
#include sys/stat.h
#include string.h
#include stdio.h
#include stdlib.husing namespace std;
//对指定节点写1
static napi_value Bq_GPIO_On(napi_env env, napi_callback_info info) {size_t argc 1;napi_value args[1] {nullptr};napi_get_cb_info(env, info, argc, args, nullptr, nullptr);napi_valuetype valuetype0;napi_typeof(env, args[0], valuetype0);char *ledPath new char[150]{};size_t buffSize 100;size_t realSize 0;napi_get_value_string_utf8(env, args[0], ledPath, buffSize, realSize);int fd;char *ret new char[50]{};fd open(ledPath, O_RDWR | O_TRUNC | O_NOCTTY);if (fd 0) {strcpy(ret, fail to open file);} else {strcpy(ret, 1);write(fd, 1, 1);close(fd);}napi_value returnValue nullptr;napi_create_string_utf8(env, ret, strlen(ret), returnValue);return returnValue;
}//对指定节点写0
static napi_value Bq_GPIO_Off(napi_env env, napi_callback_info info) {size_t argc 1;napi_value args[1] {nullptr};napi_get_cb_info(env, info, argc, args, nullptr, nullptr);napi_valuetype valuetype0;napi_typeof(env, args[0], valuetype0);char *ledPath new char[150]{};size_t buffSize 100;size_t realSize 0;napi_get_value_string_utf8(env, args[0], ledPath, buffSize, realSize);int fd;char *ret new char[50]{};fd open(ledPath, O_RDWR | O_TRUNC | O_NOCTTY);if (fd 0) {strcpy(ret, fail to open file);} else {strcpy(ret, 0);write(fd, 0, 1);close(fd);}napi_value returnValue nullptr;napi_create_string_utf8(env, ret, strlen(ret), returnValue);return returnValue;
}//查询指定节点状态
static napi_value bq_GPIO_State(napi_env env, napi_callback_info info) {size_t argc 1;napi_value args[1] {nullptr};napi_get_cb_info(env, info, argc, args, nullptr, nullptr);napi_valuetype valuetype0;napi_typeof(env, args[0], valuetype0);char *ledPath new char[150]{};size_t buffSize 100;size_t realSize 0;napi_get_value_string_utf8(env, args[0], ledPath, buffSize, realSize);char *ret new char[50]{};FILE *fp;char gpioValuePath[200];char gpioValue[2];// 构建GPIO口值文件路径snprintf(gpioValuePath, sizeof(gpioValuePath), %s, ledPath);if (access(gpioValuePath, F_OK) -1) {strcpy(ret, Error: the GPIO is not exist);napi_value returnValue nullptr;napi_create_string_utf8(env, ret, strlen(ret), returnValue);return returnValue;}// 打开GPIO口值文件fp fopen(gpioValuePath, r);if (fp NULL) {perror(Error opening GPIO value file);strcpy(ret, Error opening GPIO value file);} else {// 读取GPIO口值if (fgets(gpioValue, sizeof(gpioValue), fp) NULL) {perror(Error reading GPIO value);fclose(fp);strcpy(ret, Error reading GPIO value);} else {strcpy(ret, gpioValue);}}fclose(fp);napi_value returnValue nullptr;napi_create_string_utf8(env, ret, strlen(ret), returnValue);return returnValue;
}EXTERN_C_START static napi_value Init(napi_env env, napi_value exports) {napi_property_descriptor desc[] {{bq_GPIO_On, nullptr, Bq_GPIO_On, nullptr, nullptr, nullptr, napi_default, nullptr},{bq_GPIO_Off, nullptr, Bq_GPIO_Off, nullptr, nullptr, nullptr, napi_default, nullptr},{bq_GPIO_State, nullptr, bq_GPIO_State, nullptr, nullptr, nullptr, napi_default, nullptr}};napi_define_properties(env, exports, sizeof(desc) / sizeof(desc[0]), desc);return exports;
}
EXTERN_C_ENDstatic napi_module demoModule {.nm_version 1,.nm_flags 0,.nm_filename nullptr,.nm_register_func Init,.nm_modname entry,.nm_priv ((void *)0),.reserved {0},
};extern C __attribute__((constructor)) void RegisterEntryModule(void) { napi_module_register(demoModule); }2、NAPI函数与导出与配置 1index.d.ts
export const bq_GPIO_On: (ledPath: string) Promisestring;//节点写1export const bq_GPIO_Off: (ledPath: string) Promisestring;//节点写0export const bq_GPIO_State: (ledPath: string) Promisestring;//节点状态查询 2CMakeLists.txt
# the minimum version of CMake.
cmake_minimum_required(VERSION 3.4.1)
project(Demo_Led)set(NATIVERENDER_ROOT_PATH ${CMAKE_CURRENT_SOURCE_DIR})include_directories(${NATIVERENDER_ROOT_PATH}${NATIVERENDER_ROOT_PATH}/include)add_library(entry SHARED bq_func.cpp)
target_link_libraries(entry PUBLIC libace_napi.z.so) 3build-profile.json5 4oh-package.json5 三、Openharmony UI交互界面编写 1、UI界面编写NAPI函数引用 1index.ets 开发板控制LED灯节点地址为/sys/class/leds/pilot_lamp/brightness
import NAPI from libentry.so;//引出NAPI接口
import promptAction from ohos.promptAction;
Observed
class ledModel {public ledName: string //LED灯名称public ledAddress: string //LED灯的节点地址public ledState: boolean //LED灯状态public isLedExit: boolean //LED灯节点是否存在public ledStateCheck: string //检测返回值constructor(LedName: string, LedAddress: string, LedState: boolean false, isLedExit: boolean true, LedStateCheck: string ) {this.ledName LedNamethis.ledAddress LedAddressthis.ledState LedStatethis.isLedExit isLedExitthis.ledStateCheck LedStateCheck}
}
Entry
Component
struct Index {State message: number 0;State led: ledModel new ledModel(LED_Green,/sys/class/leds/pilot_lamp/brightness)//开发板控制LED灯节点地址/sys/class/leds/pilot_lamp/brightnessprivate setIntervalID: number -1async ledCheck() {this.led.ledStateCheck await NAPI.bq_GPIO_State(this.led.ledAddress)if (this.led.ledStateCheck 1) {this.led.ledState true} else if (this.led.ledStateCheck Error: the GPIO is not exist) {this.led.isLedExit false} else {this.led.ledState false}}async aboutToAppear() {await this.ledCheck()//状态扫描this.setIntervalID setInterval(async () {await this.ledCheck()}, 500)}aboutToDisappear() {clearInterval(this.setIntervalID)}build() {Column() {Text(点亮一个LED灯).size({ width: 100%, height: 35 }).margin({ top: 10, bottom: 10 }).textAlign(TextAlign.Center).fontSize(30).fontWeight(800)Column({ space: 10 }) {ledList({ item: this.led})}.margin({ top: 20, bottom: 10 }).size({ width: 50%, height: 50 }).justifyContent(FlexAlign.Start).alignSelf(ItemAlign.Center)}.justifyContent(FlexAlign.Center).alignItems(HorizontalAlign.Center).size({ width: 100%, height: 100% })}
}
Component
struct ledList {ObjectLink item: ledModeltip(str: string) {let show: stringswitch (str) {case 1:show 已打开;break;case 0:show 已关闭;break;default:show error: ${str}}promptAction.showToast({message: show,duration: 800})}build() {Row() {Text(${this.item.ledName}).size({ width: 70%, height: 35 }).fontSize(30).fontWeight(700).fontColor(this.item.isLedExit true ? Color.Black : #c9c9cd)Blank()Toggle({ type: ToggleType.Switch, isOn: this.item.ledState }).size({ width: 80, height: 35 }).enabled(this.item.isLedExit).onChange(async (isOn) {if (isOn) {let res: string await NAPI.bq_GPIO_On(this.item.ledAddress)this.tip(res)} else {let res: string await NAPI.bq_GPIO_Off(this.item.ledAddress)this.tip(res)}})}.width(100%)}
} 2、效果展示 1LED灭 2LED亮 四、工程代码
见附件
