用鸿蒙开发AI应用(七)触摸屏控制LED

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前言

上一篇,我们体验了一下鸿蒙上的界面的开发流程,这一篇我们继续深入一点点,尝试打通从用户态UI到内核态HDF之间的联系。其中涉及到的调用关系比较复杂,建议在“用鸿蒙开发AI应用(五)HDF 驱动补光灯”的基础上阅读本文,HDF的相关细节这里就不在赘述了。

背景知识

用户程序框架子系统包含两个大的模块:Ability子系统包管理子系统

1. Ability子系统

1.1 Ability

Ability是系统调度应用的最小单元,是能够完成一个独立功能的组件,一个应用可以包含一个或多个AbilityAbility分为两种类型:Page类型的AbilityService类型的Ability

  • Page类型的Ability:带有界面,为用户提供人机交互的能力。
  • Service类型的Ability:不带界面,为用户提供后台任务机制。

1.2 AbilitySlice

AbilitySlice是单个页面及其控制逻辑的总和,是Page类型Ability特有的组件,一个Page类型的Ability可以包含多个AbilitySlice,此时,这些页面提供的业务能力应当是高度相关的。

1.3 生命周期

生命周期是Ability被调度到启动、激活、隐藏和退出等各个状态的的统称。

Ability生命周期各状态解析:

  • UNINITIALIZED:未初始状态,为临时状态,Ability被创建后会由UNINITIALIZED状态进入INITIAL状态;
  • INITIAL:初始化状态,也表示停止状态,表示当前Ability未运行,调用Start后进入INACTIVE,同时回调开发者的OnStart生命周期回调;
  • INACTIVE:未激活状态,表示当前窗口已显示但是无焦点状态,由于Window暂未支持焦点的概念,当前状态与ACTIVE一致。
  • ACTIVE:前台激活状态,表示当前窗口已显示,并获取焦点,Ability在退到后台之前先由ACTIVE状态进入INACTIVE状态;
  • BACKGROUND: 后台状态,表示当前Ability退到后台,Ability在被销毁后由BACKGROUND状态进入INITIAL状态,或者重新被激活后由BACKGROUND状态进入ACTIVE状态。

1.4 AbilityLoader

AbilityLoader负责注册和加载开发者Ability的模块。开发者开发的Ability先要调用AbilityLoader的注册接口注册到框架中,接着Ability启动时会被实例化。

1.5 AbilityManager

AbilityManager负责AbilityKitAbility管理服务进行IPC的通信。

1.6 EventHandler

EventHandlerAbilityKit提供给开发者的用于在Ability中实现线程间通信的一个模块。

1.7 Ability运行管理服务

Ability运行管理服务是用于协调各Ability运行关系、及生命周期进行调度的系统服务。

其中,服务启动模块负责Ability管理服务的启动、注册等。

服务接口管理模块负责Ability管理服务对外能力的管理。

进程管理模块负责Ability应用所在进程的启动和销毁、及其进程信息维护等功能。Ability栈管理模块负责维护各个Ability之间跳转的先后关系。

生命周期调度模块Ability管理服务根据系统当前的操作调度Ability进入相应的状态的模块。

连接管理模块Ability管理服务Service类型Ability连接管理的模块。

1.8 AppSpawn

AppSpawn是负责创建Ability应用所在进程的系统服务,该服务有较高的权限,为Ability应用设置相应的权限,并预加载一些通用的模块,加速应用的启动。

2. 包管理子系统

包管理子系统,是OpenHarmony为开发者提供的安装包管理框架。

  • BundleKit:是包管理服务对外提供的接口,有安装/卸载接口、包信息查询接口、包状态变化监听接口。
  • 包扫描器:用来解析本地预制或者安装的安装包,提取里面的各种信息,供管理子模块进行管理,持久化。
  • 包安装子模块:安装,卸载,升级一个包;包安装服务一个单独进程的用于创建删除安装目录,具有较高的权限。
  • 包管理子模块:管理安装包相关的信息,存储持久化包信息。
  • 包安全管理子模块:签名检查、权限授予、权限管理。

HDF驱动LED(可选)

之前在内核中已经注册过一个led_driver驱动,并以led_service服务发布,这一节稍微重构一下代码,功能上没有变化,我们快速过一遍,熟悉HDF的可以自行跳过。

1. 业务代码

先新建头文件vendor\huawei\hdf\led\include\led_ctrl.h

#ifndef _LED_CTRL_H
#define _LED_CTRL_H

#include "hdf_device_desc.h"
#include "hdf_log.h"
#include "device_resource_if.h"
#include "osal_io.h"
#include "osal_mem.h"
#include "gpio_if.h"
#include "osal_irq.h"
#include "osal_time.h"

#ifdef __cplusplus
extern "C" {
#endif /* __cplusplus */

extern int32_t CtlLED(int mode);

#ifdef __cplusplus
}
#endif /* __cplusplus */

#endif /* _LED_CTRL_H */

再新建源文件 vendor\huawei\hdf\led\led_ctrl.c

#include "led_ctrl.h"

#define HDF_LOG_TAG led_driver // 打印日志所包含的标签,如果不定义则用默认定义的HDF_TAG标签

int32_t CtlLED(int mode)
{
    int32_t ret;
    uint16_t valRead;
    /* LED的GPIO管脚号 */
    // uint16_t gpio = 5 * 8 + 1;  // 红外补光灯
    uint16_t gpio = 2 * 8 + 3;  // 绿色指示灯
    // uint16_t gpio = 3 * 8 + 4;  // 红色指示灯

    /* 将GPIO管脚配置为输出 */
    ret = GpioSetDir(gpio, GPIO_DIR_OUT);
    if (ret != 0)
    {
        HDF_LOGE("GpioSerDir: failed, ret %d\n", ret);
        return ret;
    }

    if (mode == -1)
    {
        // 翻转输出口
        (void)GpioRead(gpio, &valRead);
        ret = GpioWrite(gpio, (valRead == GPIO_VAL_LOW) ? GPIO_VAL_HIGH : GPIO_VAL_LOW);
    }
    else
    {
        ret = GpioWrite(gpio, mode);
    }

    if (ret != 0)
    {
        HDF_LOGE("GpioWrite: failed, ret %d\n", ret);
        return ret;
    }
    return ret;
}

先完成对绿色指示灯的控制逻辑。

2. 驱动实现

huawei/hdf 目录下新建一个文件夹 led, 然后在其中新建一个源文件 led.c

#include "hdf_device_desc.h" // HDF框架对驱动开放相关能力接口的头文件
#include "hdf_log.h"         // HDF 框架提供的日志接口头文件
#include "led_ctrl.h"

// #define HDF_LOG_TAG led_driver // 打印日志所包含的标签,如果不定义则用默认定义的HDF_TAG标签
#define LED_WRITE_READ 1       // 读写操作码1

// Dispatch是用来处理用户态发下来的消息
int32_t LedDriverDispatch(struct HdfDeviceIoClient *client, int cmdCode, struct HdfSBuf *data, struct HdfSBuf *reply)
{
    int32_t result = HDF_FAILURE;
    HDF_LOGE("Led driver dispatch");
    if (client == NULL || client->device == NULL)
    {
        HDF_LOGE("Led driver device is NULL");
        return HDF_ERR_INVALID_OBJECT;
    }

    switch (cmdCode)
    {
    case LED_WRITE_READ:
        const char *recv = HdfSbufReadString(data);
        if (recv != NULL)
        {
            HDF_LOGI("recv: %s", recv);
            result = CtlLED(-1);
            // result = CtlLED(GPIO_VAL_HIGH);
            if (!HdfSbufWriteInt32(reply, result))
            {
                HDF_LOGE("replay is fail");
            }
            return HdfDeviceSendEvent(client->device, cmdCode, data);
        }
        break;

    default:
        break;
    }
    return result;
}

//驱动对外提供的服务能力,将相关的服务接口绑定到HDF框架
int32_t HdfLedDriverBind(struct HdfDeviceObject *deviceObject)
{
    if (deviceObject == NULL)
    {
        HDF_LOGE("Led driver bind failed!");
        return HDF_ERR_INVALID_OBJECT;
    }
    static struct IDeviceIoService ledDriver = {
        .Dispatch = LedDriverDispatch,
    };

    deviceObject->service = (struct IDeviceIoService *)(&ledDriver);
    HDF_LOGD("Led driver bind success");
    return HDF_SUCCESS;
}


// 驱动自身业务初始的接口
int32_t HdfLedDriverInit(struct HdfDeviceObject *deviceObject)
{
    if (deviceObject == NULL)
    {
        HDF_LOGE("Led driver Init failed!");
        return HDF_ERR_INVALID_OBJECT;
    }
    HDF_LOGD("Led driver Init success");
    return HDF_SUCCESS;
}

// 驱动资源释放的接口
void HdfLedDriverRelease(struct HdfDeviceObject *deviceObject)
{
    if (deviceObject == NULL)
    {
        HDF_LOGE("Led driver release failed!");
        return;
    }

    HDF_LOGD("Led driver release success");
    return;
}

// 定义驱动入口的对象,必须为HdfDriverEntry(在hdf_device_desc.h中定义)类型的全局变量
struct HdfDriverEntry g_ledDriverEntry = {
    .moduleVersion = 1,
    .moduleName = "led_driver",
    .Bind = HdfLedDriverBind,
    .Init = HdfLedDriverInit,
    .Release = HdfLedDriverRelease,
};

// 调用HDF_INIT将驱动入口注册到HDF框架中,在加载驱动时HDF框架会先调用Bind函数,再调用Init函数加载该驱动,当Init调用异常时,HDF框架会调用Release释放驱动资源并退出。
HDF_INIT(g_ledDriverEntry);

3. 驱动编译

huawei/hdf/led 目录下新建编译文件 Makefile

include $(LITEOSTOPDIR)/../../drivers/hdf/lite/lite.mk

MODULE_NAME := hdf_led_driver
LOCAL_SRCS += led_ctrl.c \
			  led.c \
              
LOCAL_INCLUDE := ./include
LOCAL_CFLAGS += -fstack-protector-strong -Wextra -Wall -Werror
include $(HDF_DRIVER)

4. 编译结果链接到内核镜像

修改 huawei/hdf/hdf_vendor.mk 文件,添加以下代码

LITEOS_BASELIB += -lhdf_led_driver  #链接生成的静态库
LIB_SUBDIRS    += $(VENDOR_HDF_DRIVERS_ROOT)/led  #驱动代码Makefile的目录

5. 驱动配置

修改 vendor/hisi/hi35xx/hi3516dv300/config/device_info/device_info.hcs配置文件,添加驱动的设备描述。

platform :: host {
    hostName = "platform_host";  // host名称,host节点是用来存放某一类驱动的容器
    priority = 50;  // host启动优先级(0-200),值越大优先级越低,建议默认配100,优先级相同则不保证host的加载顺序

    device_led :: device {                  // led设备节点
        device0 :: deviceNode {             // led驱动的DeviceNode节点
            policy = 2;                     // policy字段是驱动服务发布的策略,在驱动服务管理章节有详细介绍
            priority = 100;                 // 驱动启动优先级(0-200),值越大优先级越低,建议默认配100,优先级相同则不保证device的加载顺序
            preload = 0;                    // 驱动按需加载字段
            permission = 0666;              // 驱动创建设备节点权限
            moduleName = "led_driver";      // 驱动名称,该字段的值必须和驱动入口结构的moduleName值一致
            serviceName = "led_service";    // 驱动对外发布服务的名称,必须唯一
            deviceMatchAttr = "led_config"; // 驱动私有数据匹配的关键字,必须和驱动私有数据配置表中的match_attr值相等
        }
    } 
}

编译用户程序框架子系统

1. 添加配置文件

build/lite/platform/hi3516dv300_liteos_a/platform.json中的subsystems字段下面添加appexecfwkaafwk

{
  "subsystem": "aafwk",
  "components": [
    {
      "component": "ability",
      "optional": "true",
      "dirs": [
        "foundation/aafwk"
      ],
      "targets": [
        "//foundation/aafwk/frameworks/ability_lite:aafwk_abilitykit_lite",
        "//foundation/aafwk/frameworks/ability_lite:aafwk_abilityMain_lite",
        "//foundation/aafwk/frameworks/abilitymgr_lite:aafwk_abilityManager_lite",
        "//foundation/aafwk/services/abilitymgr_lite:aafwk_services_lite"
      ],
      "features": [
        {"enable_ohos_appexecfwk_feature_ability": "true"}
      ],
      "deps": {
        "components": [
          "hilog_a",
          "bundle_mgr",
          "system_ability_manager",
          "distributed_schedule",
          "graphic",
          "utils",
          "ipc"
        ],
        "third_party": [
          "cjson",
          "bounds_checking_function"
        ]
      }
    }
  ]
},

{
  "subsystem": "appexecfwk",
  "components": [
    {
      "component": "bundle_mgr",
      "optional": "true",
      "dirs": [
        "foundation/appexecfwk"
      ],
      "targets": [
        "//foundation/appexecfwk/services/bundlemgr_lite:appexecfwk_services_lite",
        "//foundation/appexecfwk/frameworks/bundle_lite:appexecfwk_kits_lite"
      ],
      "features": [],
      "deps": {
        "components": [
          "iam",
          "app_verify",
          "hilog_a",
          "system_ability_manager",
          "global_resource_manager",
          "graphic",
          "utils"
        ],
        "third_party": [
          "cjson",
          "zlib"
        ]
      }
    }
  ]
},

2. 添加编译文件

新建build\lite\config\subsystem\aafwk\BUILD.gn文件,

import("//build/lite/config/subsystem/lite_subsystem.gni")

lite_subsystem("aafwk") {
    subsystem_components = [
        "//foundation/aafwk/frameworks/ability_lite:aafwk_abilitykit_lite",
        "//foundation/aafwk/frameworks/abilitymgr_lite:aafwk_abilityManager_lite",
        "//foundation/aafwk/services/abilitymgr_lite:aafwk_services_lite",
    ]
}

新建/build/lite/config/subsystem/appexecfwk/BUILD.gn文件,

import("//build/lite/config/subsystem/lite_subsystem.gni")

lite_subsystem("appexecfwk") {
    subsystem_components = [
        "//foundation/appexecfwk/kits/appkit_lite:appexecfwk_kit_lite",
        "//foundation/appexecfwk/services/bundlemgr_lite:appexecfwk_services_lite",
    ]
}

3. 运行管理服务

用户程序框架有两个系统服务ability管理服务(abilityms)(bundlems),两系统服务运行于foundation进程中。

abilitymsbundlems注册到sa_manager中,sa_manager运行于foundation进程中,sa_managerabilitymsbundlems创建线程运行环境。

foundation/distributedschedule/services/safwk_lite/BUILD.gn中添加对abilitymsbundlems

deps = [    "...",]
if (ohos_kernel_type == "liteos_a") {
    deps += [        "...",        "//foundation/aafwk/services/abilitymgr_lite:abilityms",        "//foundation/appexecfwk/services/bundlemgr_lite:bundlems",        "...",    ]
}

基于AbilityKit开发的Ability

1. 主页面实现

新建源文件applications\sample\camera\myLedApp\src\main_ability.cpp

#include "main_ability.h"

namespace OHOS {
REGISTER_AA(MainAbility)

void MainAbility::OnStart(const Want &want)
{
    printf("MainAbility::OnStart\n");
    SetMainRoute("MainAbilitySlice");

    Ability::OnStart(want);
}

2. 分片页面

2.1 定义控件常量

新建源文件main_ability_slice.cpp, 屏幕大小为960x480

#include "main_ability_slice.h"

#include "ability_manager.h"
#include "components/ui_label.h"
#include "components/ui_label_button.h"
namespace OHOS
{
REGISTER_AS(MainAbilitySlice)

constexpr static int BUTTON1_POSITION_X = 380;
constexpr static int BUTTON1_POSITION_Y = 200;
constexpr static int BUTTON_WIDTH = 200;
constexpr static int BUTTON_HEIGHT = 80;
constexpr static int ROOT_VIEW_POSITION_X = 0;
constexpr static int ROOT_VIEW_POSITION_Y = 0;
constexpr static int ROOT_VIEW_WIDTH = 960;
constexpr static int ROOT_VIEW_HEIGHT = 480;
constexpr static uint8_t ROOT_VIEW_OPACITY = 255;
constexpr static uint8_t FONT_ID = 10;

constexpr static int BUTTON1_POSITION_X = 380;
constexpr static int BUTTON1_POSITION_Y = 200;
constexpr static int BUTTON_WIDTH = 200;
constexpr static int BUTTON_HEIGHT = 80;
constexpr static int ROOT_VIEW_POSITION_X = 0;
constexpr static int ROOT_VIEW_POSITION_Y = 0;
constexpr static int ROOT_VIEW_WIDTH = 960;
constexpr static int ROOT_VIEW_HEIGHT = 480;
constexpr static uint8_t ROOT_VIEW_OPACITY = 255;
constexpr static uint8_t FONT_ID = 10;
} // namespace OHOS

2.2 创建按钮和布局

在生命周期函数OnStart中,全屏放置一个rootView_,居中位置放置一个按钮button1

void MainAbilitySlice::OnStart(const Want &want)
{
    printf("MainAbilitySlice::OnStart\n");
    AbilitySlice::OnStart(want);
	
	auto button1 = new UILabelButton();
    button1->SetPosition(BUTTON1_POSITION_X, BUTTON1_POSITION_Y);
    button1->SetText("翻转 LED");
    button1->Resize(BUTTON_WIDTH, BUTTON_HEIGHT);
    button1->SetFontId(FONT_ID);
    button1->SetStyle(STYLE_TEXT_COLOR, Color::Black().full);
    button1->SetStyle(STYLE_TEXT_OPA, ROOT_VIEW_OPACITY);
    button1->SetStyle(STYLE_BACKGROUND_OPA, ROOT_VIEW_OPACITY);

    rootView_ = RootView::GetWindowRootView();
    rootView_->SetPosition(ROOT_VIEW_POSITION_X, ROOT_VIEW_POSITION_Y);
    rootView_->Resize(ROOT_VIEW_WIDTH, ROOT_VIEW_HEIGHT);

    rootView_->Add(button1);
    SetUIContent(rootView_);
}

2.3 实现驱动消息机制

这里顺便提一下,文档中DevSvcManagerClntGetService接口仅在内核态有效,可以方便的获取服务并直接调用。鸿蒙作为微内核的OS,想从用户态调用内核态函数,要么用框架的消息机制,要么自己用中断服务实现。

#define LED_WRITE_READ 1
#define LED_SERVICE "led_service"

static int OnDevEventReceived(void *priv, uint32_t id, struct HdfSBuf *data)
{
    const char *string = HdfSbufReadString(data);
    if (string == NULL)
    {
        printf("fail to read string in event data\n");
        return HDF_FAILURE;
    }
    printf("%s: dev event received: %u %s\n", (char *)priv, id, string);

    return HDF_SUCCESS;
}

static int SendEvent(struct HdfIoService *serv, const char *eventData)
{
    int ret = 0;
    struct HdfSBuf *data = HdfSBufObtainDefaultSize();
    if (data == NULL)
    {
        printf("fail to obtain sbuf data\n");
        return 1;
    }

    struct HdfSBuf *reply = HdfSBufObtainDefaultSize();
    if (reply == NULL)
    {
        printf("fail to obtain sbuf reply\n");
        ret = HDF_DEV_ERR_NO_MEMORY;
        HdfSBufRecycle(data);
        return ret;
    }

    if (!HdfSbufWriteString(data, eventData))
    {
        printf("fail to write sbuf\n");
        ret = HDF_FAILURE;
        HdfSBufRecycle(data);
        HdfSBufRecycle(reply);
        return ret;
    }

    ret = serv->dispatcher->Dispatch(&serv->object, LED_WRITE_READ, data, reply);
    if (ret != HDF_SUCCESS)
    {
        printf("fail to send service call\n");
        HdfSBufRecycle(data);
        HdfSBufRecycle(reply);
        return ret;
    }

    int replyData = 0;
    if (!HdfSbufReadInt32(reply, &replyData))
    {
        printf("fail to get service call reply\n");
        ret = HDF_ERR_INVALID_OBJECT;
        HdfSBufRecycle(data);
        HdfSBufRecycle(reply);
        return ret;
    }
    printf("Get reply is: %d\n", replyData);

    HdfSBufRecycle(data);
    HdfSBufRecycle(reply);
    return ret;
}

2.4 加入点击事件

每次点击按钮,向内核态发送一次消息。

auto onClick = [this](UIView &view, const Event &event) -> bool {
    printf("led button pressed\n");

    struct HdfIoService *serv = HdfIoServiceBind(LED_SERVICE, 0);
    if (serv == NULL)
    {
        printf("fail to get service %s\n", LED_SERVICE);
        return false;
    }

    static struct HdfDevEventlistener listener = {
        .callBack = OnDevEventReceived,
        .priv = (void *)"Service0"};

    if (HdfDeviceRegisterEventListener(serv, &listener) != HDF_SUCCESS)
    {
        printf("fail to register event listener\n");
        return false;
    }

    const char *send_cmd = "toggle LED";

    if (SendEvent(serv, send_cmd))
    {
        printf("fail to send event\n");
        return false;
    }

    if (HdfDeviceUnregisterEventListener(serv, &listener))
    {
        printf("fail to  unregister listener\n");
        return false;
    }

    HdfIoServiceRecycle(serv);

    return true;
};

2.5 注销页面

在生命周期函数OnStop中,删除所有节点,回收系统资源。

void DeleteViewChildren(UIView *view)
{
    if (view == nullptr) {
        return;
    }
    while (view != nullptr) {
        UIView *tempView = view;
        view = view->GetNextSibling();
        if (tempView->IsViewGroup()) {
            DeleteViewChildren(dynamic_cast<UIViewGroup *>(tempView)->GetChildrenHead());
        }
        if (tempView->GetParent()) {
            dynamic_cast<UIViewGroup *>(tempView->GetParent())->Remove(tempView);
        }
        delete tempView;
    }
}

void MainAbilitySlice::OnStop()
{
    printf("MainAbilitySlice::OnStop\n");
    AbilitySlice::OnStop();
    DeleteViewChildren(rootView_);
}

3. 编译配置

新增 applications\sample\camera\myLedApp\BUILD.gn文件

import("//build/lite/config/component/lite_component.gni")
import("//build/lite/config/subsystem/aafwk/config.gni")

HDF_FRAMEWORKS = "//drivers/hdf/frameworks"
src_path = "//applications/sample/camera/myLedApp/src"

lite_library("ledability") {
    target_type = "shared_library"
    ldflags = [
        "-shared",
    ]
    sources = [
        "${src_path}/main_ability.cpp",
        "${src_path}/main_ability_slice.cpp",
    ]

    include_dirs = [
        ".",
        "//foundation/aafwk/frameworks/ability_lite/example/entry/src/main/cpp",
        "//foundation/aafwk/interfaces/innerkits/abilitymgr_lite",
        "//foundation/aafwk/interfaces/kits/ability_lite",
        "//foundation/aafwk/interfaces/kits/want_lite",
        "//foundation/appexecfwk/interfaces/kits/bundle_lite",
        "//foundation/appexecfwk/utils/bundle_lite",
        "//foundation/communication/interfaces/kits/ipc_lite",
        "//foundation/graphic/lite/interfaces/kits/config",
        "//foundation/graphic/lite/interfaces/kits/ui",
        "//foundation/graphic/lite/interfaces/kits/utils",
        "//kernel/liteos_a/kernel/common",
        "//kernel/liteos_a/kernel/include",
        "//drivers/hdf/lite/include/host",
        "$HDF_FRAMEWORKS/ability/sbuf/include",        
        "$HDF_FRAMEWORKS/core/shared/include",
        "$HDF_FRAMEWORKS/core/host/include",
        "$HDF_FRAMEWORKS/core/master/include",
        "$HDF_FRAMEWORKS/include/core",
        "$HDF_FRAMEWORKS/include/utils",
        "$HDF_FRAMEWORKS/utils/include",
        "$HDF_FRAMEWORKS/include/osal",
        "//kernel/liteos_a/platform/include",
        "$HDF_FRAMEWORKS/adapter/syscall/include",
        "$HDF_FRAMEWORKS/adapter/vnode/include",
    ]

    deps = [
        "//foundation/aafwk/frameworks/ability_lite:aafwk_abilitykit_lite",
        "//drivers/hdf/lite/manager:hdf_core",
        "//drivers/hdf/lite/adapter/osal/posix:hdf_posix_osal",
    ]

    defines = [
        "OHOS_APPEXECFWK_BMS_BUNDLEMANAGER",
    ]

    if (enable_ohos_appexecfwk_feature_ability == true) {
        deps += [
            "//foundation/graphic/lite/frameworks/ui:ui",
        ]
        defines += [
            "ENABLE_WINDOW=1",
            "ABILITY_WINDOW_SUPPORT"
        ]
    }
    output_dir = "$root_out_dir/dev_tools/led"
}

4. 应用配置文件

新建 applications\sample\camera\myLedApp\config.json

{
    "app": {
        "bundleName": "com.bluishfish.ledability",
        "vendor": "huawei",
        "version": {
            "code": 1,
            "name": "1.0"
        },
       "apiVersion": {
          "compatible": 3,
          "target": 3
       }
    },
    "deviceConfig": {
        "default": {
            "keepAlive": false
        }
    },
    "module": {
        "deviceType": [
            "smartVision"
        ],
        "distro": {
            "deliveryWithInstall": true,
            "moduleName": "ledability",
            "moduleType": "entry"
        },
        "abilities": [{
            "name": "MainAbility",
            "icon": "assets/entry/resources/base/media/icon.png",
            "label": "Led Ability",
            "launchType": "standard",
            "type": "page",
            "visible": true
        }
        ]
    }
}

5. 板级编译配置

复制 build/lite/product/ipcamera_hi3516dv300.json,改名为my_hi3516dv300在子系统里加入

{
  "ohos_version": "OpenHarmony 1.0",
  "board": "hi3516dv300",
  "kernel": "liteos_a",
  "compiler": "clang",
  "subsystem": [
    {
      "name": "aafwk",
      "component": [
            "......",
            { "name": "ability_led", "dir": "//applications/sample/camera/myLedApp:ledability", "features": []}
        ]
"......"

6. 编译应用

python build.py my_hi3516dv300 -b debug

将系统烧录到开发板上。

7. 打包应用

assets\entry\resources\base\media\目录下放置一个icon.png作为启动图标。

applications\sample\camera\myLedApp\config.jsonZ:\openharmony\out\my_hi3516dv300\dev_tools\led\libledability.so打包压缩成zip

改名为ledability.hap ,复制到NFS共享目录

8. 安装Hap

mkdir nfs
mount 192.168.1.57:/nfs /nfs nfs
./nfs/dev_tools/bin/bm set -s disable
./nfs/dev_tools/bin/bm install -p ./nfs/ledability.hap

9. 运行程序

./nfs/dev_tools/bin/aa start -p com.bluishfish.ledability -n MainAbility

完美!

总结

整理一下思路,

我们先用AbilityKit绘制Ability页面,在其button1上绑定一个按钮事件;

触发后,由用户子系统寻找到led_server服务,向HDF框架发送消息;

内核驱动led_driver接收到消息后,调用底层GPIO控制LED翻转,并将操作状态以reply消息的形式传回用户侧;

后续可以接着根据返回状态更新下界面。

好了,在此基础上美化下界面,接个继电器做个智能家居的App应该不是难事了。

源码下载

下一篇预告

C++来写UI开发效率总是不如javajs高的,

何况还没法用上DevEco Studio辅助设计,

下一篇我们尝试实现更多的设备能力,

并用JS框架来访问内核层,

敬请期待...