Android Automotive架构与流程：VehicleHAL，CarService

2. Manager注册回调，然后通过onChangeEvent获取汽车属性值CarPropertyValue的改变：

mCarHvacManager.registerCallback(mHvacCallback);

private CarHvacEventCallback mHvacCallback = new CarHvacEventCallback() {

@Override

public void onChangeEvent(CarPropertyValue carPropertyValue) {

//Log.d(TAG, "onChangeEvent id = " + toHexString(carPropertyValue.getPropertyId()));

int value = -1;

int areaId;

switch (carPropertyValue.getPropertyId()) {

case ID_HVAC_POWER_ON:

value = (Integer)carPropertyValue.getValue();

areaId = carPropertyValue.getAreaId();

break;

default:

break;

}

}

@Override

public void onErrorEvent(int i, int i1) { }

};

3. SET 和 GET，以HVAC空调为例：

mCarHvacManager.setIntProperty(ID_HVAC_LOCK_VENTILATION_ON, VehicleAreaType.VEHICLE_AREA_TYPE_GLOBAL, HVAC_ON);

float temp = mCarHvacManager.getFloatProperty(ID_HVAC_TEMPERATURE_SET, SEAT_ROW_1_LEFT);

VehicleAreaType分为GLOBAL（全局）、WINDOW（车窗）、MIRROR（镜子）、SEAT（座椅）、DOOR（车门）、WHEEL（车轮）等：

enum VehicleArea : int32_t {

GLOBAL = 0x01000000,

/** WINDOW maps to enum VehicleAreaWindow */

WINDOW = 0x03000000,

/** MIRROR maps to enum VehicleAreaMirror */

MIRROR = 0x04000000,

/** SEAT maps to enum VehicleAreaSeat */

SEAT = 0x05000000,

/** DOOR maps to enum VehicleAreaDoor */

DOOR = 0x06000000,

/** WHEEL maps to enum VehicleAreaWheel */

WHEEL = 0x07000000,

/** IN_OUT_CAR maps to enum VehicleAreaInOutCar，车内外 */

IN_OUT_CAR = 0x08000000,

MASK = 0x0f000000,

};

CarAPI (car-lib:android.car.jar)

1.createCar：

public static Car createCar(Context context, ServiceConnection serviceConnectionListener, @Nullable Handler handler) {

if (!context.getPackageManager().hasSystemFeature(PackageManager.FEATURE_AUTOMOTIVE)) {

Log.e(CarLibLog.TAG_CAR, “FEATURE_AUTOMOTIVE not declared while android.car is used”);

return null;

}

try {

return new Car(context, serviceConnectionListener, handler);

} catch (IllegalArgumentException e) { // Expected when car service loader is not available.

}

return null;

}

2. getCarManager(“serviceName”) -> createCarManager(“serviceName”, IBinder)

public Object getCarManager(String serviceName) throws CarNotConnectedException {

CarManagerBase manager;

ICar service = getICarOrThrow();

synchronized (mCarManagerLock) {

manager = mServiceMap.get(serviceName);

if (manager == null) {

try {

if(TBOX_SERVICE.equals(serviceName)){

manager = createCarManager(serviceName, null);

return manager;

}

IBinder binder = service.getCarService(serviceName);

if (binder == null) {

Log.w(CarLibLog.TAG_CAR, “could not get binder for service:” + serviceName);

return null;

}

manager = createCarManager(serviceName, binder);

if (manager == null) {

Log.w(CarLibLog.TAG_CAR, “could not create manager for service:” + serviceName);