车载AAOS系统Android CarService接口定义全链路设计之车载语音助手为例
采用 AAOS 的车载 Android 系统，一次性集成即可让车规硬件直接运行完整 Android 生态，通过 CarService 深度控制空调、车窗等车控功能，使车载的接口标准化规范化，显著缩短开发周期、降低维护成本并拓展持续盈利空间，下面介绍aaos应用适配的架构设计，以车载语音助手为例，从给上层调用的carlib接口到carservice服务,到hal层语音相关接口，应用案例如下。
1、在carlib中添加应用与carservice的aidl接口及调用方法
在\android11.0\packages\servicesCar\car-lib\src\android\car\路径下添加Voice目录，在Voice目录下添加语音助手的上层调用及数据回调接口，如下：
语音助手的上层调用接口：
android11.0\packages\servicesCar\car-lib\src\android\car\IVoiceRecognitionService.aidl
interface IVoiceRecognitionService { void startVoiceRecognition(); void stopVoiceRecognition(); void setVoiceCallback(IVoiceCallback callback); }语音助手的回调接口：
// android11.0\packages\servicesCar\car-lib\src\android\car\IVoiceCallback.aidl
interface IVoiceCallback { void onVoiceResult(String result); void onVoiceError(int errorCode); }语音接口管理类：
// android11.0\packages\servicesCar\car-lib\src\android\car\CarVoiceManager.java
public class CarVoicemanager extends IVoiceCallback.Stub{ private IVoiceRecognitionService mIVoiceRecognitionService; private List<IVoiceCallback > mVoiceCallbackList=new ArrayList<>(); private CarVoicemanager() { init(); } /** * 静态内部类方式构造单例（线程安全） * @hide */ private static class SingleHolder { static final CarVoicemanager sInstance = new CarVoicemanager(); } /** * 内部类方式获取单例 * * @return * @hide */ @NonNull public static CarVoicemanager getInstance() { return CarVoicemanager.SingleHolder.sInstance; } /** * 初始化服务 * //针对初始化做一些等待处理 * @hide */ private void init() { try { IBinder mCarServiceBinder = ServiceManager.getService(Car.CAR_SERVICE_BINDER_SERVICE_NAME); if (mCarServiceBinder == null) { Log.e(TAG, "car service not start, waited for car service !!!"); return; } ICar mCarService = ICar.Stub.asInterface(mCarServiceBinder); if (mCarService == null) { Log.e(TAG, "car service not register !!!"); return; } IBinder binder = mCarService.getCarService(Car.VOICE_SERVICE); if (binder == null) { Log.e(TAG, "voiceservice not register !!!"); return; } mIVoiceRecognitionService = IVoiceRecognitionService .Stub.asInterface(binder); if (mIVoiceRecognitionService == null) { Log.e(TAG, "mIVoiceRecognitionService get failed !!!"); return; } } } catch (RemoteException e) { e.printStackTrace(); } } public void startVoiceRecognition(){ if(mIVoiceRecognitionService!=null){ mIVoiceRecognitionService.startVoiceRecognition(); } } public void stopVoiceRecognition(){ if(mIVoiceRecognitionService!=null){ mIVoiceRecognitionService.stopVoiceRecognition(); } } public void setVoiceCallback(IVoiceCallback callback){ if(!mVoiceCallbackList.contains(callback)){ mVoiceCallbackList.add(callback); } } @Override void onVoiceResult(String result){ for(VoiceCallback callback:mVoiceCallbackList){ callback.onVoiceResult(result); } } @Override void onVoiceError(int errorCode){ for(VoiceCallback callback:mVoiceCallbackList){ callback.onVoiceError(errorCode); } } }2、在CarService应用增加CarVoiceService及跟hal通信相关接口
在// android11.0/packages/services/Car/service/src/com/android/car/目录下增加voice目录，在目录下创建CarVoiceService类,如下：
public class CarVoiceService extends IVoiceRecognitionService.Stub implements CarServiceBase { private final static String TAG = "CarVoiceService"; private final int START_VOICE_RECOGINZED = 1; private final int STOP_VOICE_RECOGINZED = 2; private VoiceMessage mVoiceMessage; private IHalVoice mIHalVoice; public CarVoiceService(@NonNull Context context) { // hal接口通过hidl接口生成IHalVoice.java类，通过getService可以获取接口对象 mIHalVoice = IHalVoice.getService(); mVoiceMessage = new mVoiceMessage(mHal); mVoiceMessage.init(mIHalVoice); } @Override public void startVoiceRecognition(){ mIHalVoice.sendVoiceCmdToCpp(START_VOICE_RECOGINZED); } @Override public void stopVoiceRecognition(){ mIHalVoice.sendVoiceCmdToCpp(STOP_VOICE_RECOGINZED); } @Override public void setVoiceCallback(IVoiceCallback callback){ mVoiceMessage.setVoiceCallback(callback); } }创建hal消息管理类：
// android11.0/packages/services/Car/service/src/com/android/car/voice/VoiceHalMessage.java
public class VoiceHalMessage { private IVoiceCallback mVoiceCallback; private IHalVoice mIHalVoice; public VoiceHalMessage (mIHalVoice hal){ mIhalVoice = hal; } public void init(){ mIhalVoice.registerLitener(mIHalVoiceCallback); } public void setCallbackListener(VoiceCallback listenter){ mVoiceCallback = listenter; } private final IHalVoiceCallbackCallback mIHalVoiceCallback = new IHalVoiceCallback.Stub() { @Override public void onVoiceMessage(int code,String message) { if(code==0){ mVoiceCallback.onVoiceResult(message); return; } mVoiceCallback.onVoiceError(message); } } }在// android11.0/packages/services/Car/service/src/com/android/car/ICarImpl.java类中
public class ICarImpl{ peivate CarVoiceService mCarVoiceService; public ICarImpl(){ //省略 mCarVoiceService = new mCarVoiceService(serviceContext); CarLocalServices.addService(CarVoiceService.class, mCarVoiceService); } @Override public IBinder getCarService(String serviceName) { switch (serviceName) { //其他省略 case Car.VOICE_SERVICE: return mCarVoiceService; default: return null; } } }在// android11.0/packages/services/Android.bp，如下：
android_app { name: "CarService", srcs: car_service_sources, resource_dirs: ["res"], platform_apis: true, // Each update should be signed by OEMs certificate: "platform", privileged: true, optimize: { proguard_flags_files: ["proguard.flags"], enabled: false, }, libs: ["android.car"], android_app { name: "CarService", ... static_libs: [ "car-frameworks-service", "android.hardware.voice@1.0-java-static", // <-- 语音 HAL Java 依赖 ], } required: ["privapp_whitelist_com.android.car"], // Disable build in PDK, missing aidl import breaks build product_variables: { pdk: { enabled: false, }, }, }3、在hal层增加hidl接口及语音原子能力的相关接口：
在android11.0\hardware\interfaces\voice\目录下添加hal接口文集如下：
语音指令发送IVoiceHal.hal
package android.hardware.voice@1.1; import @1.0::IVoiceHal; interface IVoiceHalextends @1.0::IVoiceHal{ sendVoiceCmdToCpp(int32_t code)； } enum VoiceCmd : int32_t { START_VOICE_RECOGINZED = 1, STOP_VOICE_RECOGINZED = 2, };语音消息回调IHalVoiceCallback .hal
package android.hardware.voice@1.1; import @1.0::IHalVoiceCallback ; interface IHalVoiceCallback extends @1.0::IHalVoiceCallback { oneway onVoiceMessage(int32_t code,String message ); }语音接口C++ 实现：android11.0/hardware/interfaces/voice/default/VoiceRecognition.h
把指令 enum 同步过来，并声明 sendVoiceCmd 接口：
C++ 语音接口实现：android11.0/hardware/interfaces/voice/default/VoiceRecognition.cpp
#include "VoiceRecognition.h" #include <android-base/logging.h> namespace android::hardware::voice::V1_0::implementation { bool VoiceRecognition::sendVoiceCmdToCpp(VoiceCmd cmd) { switch (cmd) { case VoiceCmd::START_VOICE_RECOGINZED: handleStart(); return true; case VoiceCmd::STOP_VOICE_RECOGINZED: handleStop(); return true; default: LOG(ERROR) << "Unknown voice cmd " << static_cast<int32_t>(cmd); return false; } } void VoiceRecognition::startRecognition() { LOG(INFO) << ">>> native START_VOICE_RECOGINZED"; // 这里放入启动识别算法 / 打开 MIC / 通知 DSP 等代码 } void VoiceRecognition::stopRecognition() { LOG(INFO) << ">>> native STOP_VOICE_RECOGINZED"; // 这里放入停止识别算法 / 关闭 MIC / 通知 DSP 等代码 } }在android11.0/hardware/interfaces/voice/目录下添加Android.bp
hidl_interface { name: "android.hardware.voice@1.0", root: "android.hardware", vndk: { enabled: true, }, srcs: [ "types.hal", "IHalVoiceCallback.hal", "IVoiceHal.hal", ], interfaces: [ "android.hidl.base@1.0", ], gen_java: true, }