前言

1、Google官网上是这样介绍汽车架构的。

  • Car App：包括OEM和第三方开发的App
  • Car API：内有包含 CarSensorManager 在内的 API。位于 /platform/packages/services/Car/car-lib。
  • CarService：系统中与车相关的服务，位于 /platform/packages/services/Car/目录。
  • 车载 HAL：用于定义 OEM 可以实现的车辆属性的接口。包含属性元数据（例如，车辆属性是否为 int 以及允许使用哪些更改模式）。位于 hardware/libhardware/include/hardware/vehicle.h。如需了解基本参考实现，请参阅 hardware/libhardware/modules/vehicle/。

2、 Framework CarService

1、Android O/P为Automotive场景提供了一系列的服务，这些服务统被称为CarService。它们与HAL层的VehicleHAL通信，进而通过车载总线(例如CAN总线)与车身进行通讯，同时它们还为应用层的APP提供接口，从而让APP能够实现对车身的控制与状态的显示。

  • Car***Manage位于packages/services/Car/car-lib/src/android/car/hardware目录，
  • Car***Service位于packages/services/Car/service/src/com/android/car目录。

一、目录结构

1、CarService主要位于packages/services/Car/目录。

├── Android.mk├── apicheck.mk├── apicheck_msg_current.txt├── apicheck_msg_last.txt├── car-cluster-logging-renderer//LoggingClusterRenderingService继承InstrumentClusterRenderingService├── car-default-input-service //按键消息处理├── car-lib //提供给汽车App特有的接口，许多定制的模块都在这里实现，包括Sensor,HVAC,Cabin,ActiveParkingAssiance,Diagnostic,Vendor等├── car-maps-placeholder//地图软件相关├── car_product //系统编译相关├── car-support-lib //android.support.car├── car-systemtest-lib//系统测试相关├── car-usb-handler //开机自启，用于管理车机USB├── CleanSpec.mk├── evs├── obd2-lib├── PREUPLOAD.cfg├── procfs-inspector├── service//com.android.car是一个后台运行的组件，可以长时间运行并且不需要和用户去交互的，这里即使应用被销毁，它也可以正常工作├── tests├── tools //是一系列的工具，要提到的是里面的emulator，测试需要用到的。python写的，通过adb可以连接vehicleHal的工具，用于模拟测试├── TrustAgent└── vehicle-hal-support-lib

2、Car APP

1、Car APP的相关源码位于packages/apps/Car/目录，其中packages/services/Car/car_product/build/car.mk里面决定了需要编译哪些相关apk（system/priv-app）。

packages/services/Car/car_product/build/car.mk

# Common make file for all car buildsPRODUCT_PUBLIC_SEPOLICY_DIRS += packages/services/Car/car_product/sepolicy/publicPRODUCT_PRIVATE_SEPOLICY_DIRS += packages/services/Car/car_product/sepolicy/privatePRODUCT_PACKAGES += \Bluetooth \CarActivityResolver \CarDeveloperOptions \CarSettingsIntelligence \CarManagedProvisioning \OneTimeInitializer \CarProvision \StatementService \SystemUpdaterPRODUCT_PACKAGES += \clatd \pppd \screenrecord# This is for testingifneq (,$(filter userdebug eng, $(TARGET_BUILD_VARIANT)))PRODUCT_PACKAGES += \DefaultStorageMonitoringCompanionApp \EmbeddedKitchenSinkApp \GarageModeTestApp \ExperimentalCarService \BugReportApp \NetworkPreferenceApp \SampleCustomInputService \AdasLocationTestApp \curl \# SEPolicy for test apps / servicesBOARD_SEPOLICY_DIRS += packages/services/Car/car_product/sepolicy/testendif# ClusterOsDouble is the testing app to test Cluster2 framework and it can handle Cluster VHAL# and do some Cluster OS role.ifeq ($(ENABLE_CLUSTER_OS_DOUBLE), true)PRODUCT_PACKAGES += ClusterHomeSample ClusterOsDoubleelse# DirectRenderingCluster is the sample app for the old Cluster framework.PRODUCT_PACKAGES += DirectRenderingClusterendif# ENABLE_CLUSTER_OS_DOUBLEPRODUCT_COPY_FILES += \frameworks/av/media/libeffects/data/audio_effects.conf:system/etc/audio_effects.confPRODUCT_PROPERTY_OVERRIDES += \persist.bluetooth.enablenewavrcp=false \ro.carrier=unknownPRODUCT_SYSTEM_DEFAULT_PROPERTIES += \config.disable_systemtextclassifier=true###### Suggested values for multi-user properties - can be overridden#### Enable headless system user modePRODUCT_SYSTEM_DEFAULT_PROPERTIES += \ro.fw.mu.headless_system_user?=true# Enable user pre-creationPRODUCT_SYSTEM_DEFAULT_PROPERTIES += \android.car.number_pre_created_users?=1 \android.car.number_pre_created_guests?=1# Enable User HAL integration# NOTE: when set to true, VHAL must also implement the user-related properties,# otherwise CarService will ignore itPRODUCT_SYSTEM_DEFAULT_PROPERTIES += \android.car.user_hal_enabled?=true### end of multi-user properties #### Overlay for Google network and fused location providers$(call inherit-product, device/sample/products/location_overlay.mk)$(call inherit-product-if-exists, frameworks/webview/chromium/chromium.mk)$(call inherit-product, packages/services/Car/car_product/build/car_base.mk)# OverridesPRODUCT_BRAND := genericPRODUCT_DEVICE := genericPRODUCT_NAME := generic_car_no_telephonyPRODUCT_IS_AUTOMOTIVE := truePRODUCT_PROPERTY_OVERRIDES := \ro.config.ringtone=Girtab.ogg \ro.config.notification_sound=Tethys.ogg \ro.config.alarm_alert=Oxygen.ogg \$(PRODUCT_PROPERTY_OVERRIDES) \PRODUCT_PROPERTY_OVERRIDES += \keyguard.no_require_sim=true# TODO(b/205189147): Remove the following change after the proper fix is landed.# Uses the local KeyGuard animation to resolve TaskView misalignment issue after display-on.PRODUCT_SYSTEM_PROPERTIES += \persist.wm.enable_remote_keyguard_animation=0# Automotive specific packagesPRODUCT_PACKAGES += \CarFrameworkPackageStubs \CarService \CarShell \CarDialerApp \CarRadioApp \OverviewApp \CarSystemUI \LocalMediaPlayer \CarMediaApp \CarMessengerApp \CarHTMLViewer \CarMapsPlaceholder \CarLatinIME \CarSettings \CarUsbHandler \android.car \car-frameworks-service \com.android.car.procfsinspector \libcar-framework-service-jni \ScriptExecutor \# RROsPRODUCT_PACKAGES += \CarPermissionControllerRRO \# System Server components# Order is important: if X depends on Y, then Y should precede X on the list.PRODUCT_SYSTEM_SERVER_JARS += car-frameworks-service# TODO: make the order optimal by appending 'car-frameworks-service' at the end# after its dependency 'services'. Currently the order is violated because this# makefile is included before AOSP makefile.PRODUCT_BROKEN_SUBOPTIMAL_ORDER_OF_SYSTEM_SERVER_JARS := true# Boot animationPRODUCT_COPY_FILES += \packages/services/Car/car_product/bootanimations/bootanimation-832.zip:system/media/bootanimation.zipPRODUCT_LOCALES := \en_US \af_ZA \am_ET \ar_EG ar_XB \as_IN \az_AZ \be_BY \bg_BG \bn_BD \bs_BA \ca_ES \cs_CZ \da_DK \de_DE \el_GR \en_AU en_CA en_GB en_IN en_XA \es_ES es_US \et_EE \eu_ES \fa_IR \fi_FI \fil_PH \fr_CA fr_FR \gl_ES \gu_IN \hi_IN \hr_HR \hu_HU \hy_AM \id_ID \is_IS \it_IT \iw_IL \ja_JP \ka_GE \kk_KZ \km_KH km_MH \kn_IN \ko_KR \ky_KG \lo_LA \lv_LV \lt_LT \mk_MK \ml_IN \mn_MN \mr_IN \ms_MY \my_MM \ne_NP \nl_NL \no_NO \or_IN \pa_IN \pl_PL \pt_BR pt_PT \ro_RO \ru_RU \si_LK \sk_SK \sl_SI \sq_AL \sr_RS \sv_SE \sw_TZ \ta_IN \te_IN \th_TH \tr_TR \uk_UA \ur_PK \uz_UZ \vi_VN \zh_CN zh_HK zh_TW \zu_ZAPRODUCT_BOOT_JARS += \android.carPRODUCT_HIDDENAPI_STUBS := \android.car-stubs-dexPRODUCT_HIDDENAPI_STUBS_SYSTEM := \android.car-system-stubs-dexPRODUCT_HIDDENAPI_STUBS_TEST := \android.car-test-stubs-dex# Disable Prime Shader Cache in SurfaceFlinger to make it available fasterPRODUCT_PROPERTY_OVERRIDES += \service.sf.prime_shader_cache=0