Java 层
CameraManager: openCamera() -> openCameraForUid() -> openCameraDeviceUserAsync() ->
- 构造 CameraDeviceImpl deviceImpl = new CameraDeviceImpl();
- 如果支持 camera2 则： 2.1 ICameraService cameraService = CameraManagerGlobal.get().getCameraService(); 否则： 2.2 CameraDeviceUserShim.connectBinderShim(callbacks, id);
native 层（接2.1）
系统服务 ICameraService 是在 native 层实现的，service 名称为 media.camera，其实现位于 frameworks/av/services/camera/CameraService.cpp，头文件是同级目录下的 CameraService.h 我们看 connectDevice() 的具体实现 CameraService.h::connectDevice() -> CameraService.cpp::connectDevice() -> connectHelper() -> makeClient() -> client = new CameraClient() client = new camera2Client() client.initialize() -> frameworks/av/services/camera/libcameraservice/api2/CameraDeviceClient.h frameworks/av/services/camera/libcameraservice/api2/CameraDeviceClient.cpp initializeImpl() -> 父类初始化 Camera2ClientBase::initialize() 在 CameraClient.cpp::initialize() 中初始化 mHardware = new CameraHardwareInterface(), 接着进行 hardware 初始化：mHardware::initialize() -> CameraProviderManager.cpp::openSession() -> 打开设备：上电、初始化、返回 session 句柄 mHardware::setCallbacks(notifyCallback, dataCallback, …) 注意此处传递的是函数指针 enableMsgType() -> mHardware::enableMsgType(error, zoom, focus, metadata msg, …) 返回 client 引用