- ①首先拿到
CameraManagerCameraManger是对CameraService的调用封装
CameraManager cameraManager = (CameraManager) getSystemService(Context.CAMERA_SERVICE);
- ② 在获取到
CameraList支持的摄像头列表
String[] cameraIdList = cameraManager.getCameraIdList();
// 根据CameraId 获取到当前摄像头的具体详情信息
cameraManager.getCameraCharacteristics(cameraId);
- ③ 打开指定的摄像头,就可以在回调中拿到CameraDevices 对象，进行拍照和预览了
cameraManager.openCamera(cameraId, callback, null);
FW层具体初始化流程
-
CameraManager是一个MangerServise 他的初始化是在SystemServiceRegistry中创建的
registerService(Context.CAMERA_SERVICE, CameraManager.class,
new CachedServiceFetcher() {
@Override
public CameraManager createService(ContextImpl ctx) {
return new CameraManager(ctx);
}});
CameraManager
- CameraManager 中封装了，ICameraService 的实例通过binder ，获取摄像头一些基本信息，调用 openCamera打开相机
- openCamera 最中调用到
openCameraDeviceUserAsync中来
private CameraDevice openCameraDeviceUserAsync(String cameraId,
CameraDevice.StateCallback callback, Executor executor, final int uid)
throws CameraAccessException {
// 获取到摄像头的配置信息
CameraCharacteristics characteristics = getCameraCharacteristics(cameraId);
CameraDevice device = null;
synchronized (mLock) {
ICameraDeviceUser cameraUser = null;
// 拿到 CameraDevice
android.hardware.camera2.impl.CameraDeviceImpl deviceImpl =
new android.hardware.camera2.impl.CameraDeviceImpl(
cameraId,
callback,
executor,
characteristics,
mContext.getApplicationInfo().targetSdkVersion);
ICameraDeviceCallbacks callbacks = deviceImpl.getCallbacks();
try {
if (supportsCamera2ApiLocked(cameraId)) {
// Use cameraservice's cameradeviceclient implementation for HAL3.2+ devices
ICameraService cameraService = CameraManagerGlobal.get().getCameraService();
if (cameraService == null) {
throw new ServiceSpecificException(
ICameraService.ERROR_DISCONNECTED,
"Camera service is currently unavailable");
}
// 调用CameraService .cpp 中的 connectDevice 方法
cameraUser = cameraService.connectDevice(callbacks, cameraId,
mContext.getOpPackageName(), uid);
} else {
// Use legacy camera implementation for HAL1 devices
int id;
try {
id = Integer.parseInt(cameraId);
} catch (NumberFormatException e) {
throw new IllegalArgumentException("Expected cameraId to be numeric, but it was: "
+ cameraId);
}
Log.i(TAG, "Using legacy camera HAL.");
cameraUser = CameraDeviceUserShim.connectBinderShim(callbacks, id,
getDisplaySize());
}
} catch (ServiceSpecificException e) {
if (e.errorCode == ICameraService.ERROR_DEPRECATED_HAL) {
throw new AssertionError("Should've gone down the shim path");
} else if (e.errorCode == ICameraService.ERROR_CAMERA_IN_USE ||
e.errorCode == ICameraService.ERROR_MAX_CAMERAS_IN_USE ||
e.errorCode == ICameraService.ERROR_DISABLED ||
e.errorCode == ICameraService.ERROR_DISCONNECTED ||
e.errorCode == ICameraService.ERROR_INVALID_OPERATION) {
// Received one of the known connection errors
// The remote camera device cannot be connected to, so
// set the local camera to the startup error state
deviceImpl.setRemoteFailure(e);
if (e.errorCode == ICameraService.ERROR_DISABLED ||
e.errorCode == ICameraService.ERROR_DISCONNECTED ||
e.errorCode == ICameraService.ERROR_CAMERA_IN_USE) {
// Per API docs, these failures call onError and throw
throwAsPublicException(e);
}
} else {
// Unexpected failure - rethrow
throwAsPublicException(e);
}
} catch (RemoteException e) {
// Camera service died - act as if it's a CAMERA_DISCONNECTED case
ServiceSpecificException sse = new ServiceSpecificException(
ICameraService.ERROR_DISCONNECTED,
"Camera service is currently unavailable");
deviceImpl.setRemoteFailure(sse);
throwAsPublicException(sse);
}
// TODO: factor out callback to be non-nested, then move setter to constructor
// For now, calling setRemoteDevice will fire initial
// onOpened/onUnconfigured callbacks.
// This function call may post onDisconnected and throw CAMERA_DISCONNECTED if
// cameraUser dies during setup.
deviceImpl.setRemoteDevice(cameraUser);
device = deviceImpl;
}
return device;
}
CameraDeviceImpl
- CameraDeviceImpl 中
setRemoteDevice会回调设备打开成功的open 监听他继承于CameraDevice类
public void setRemoteDevice(ICameraDeviceUser remoteDevice) throws CameraAccessException {
synchronized(mInterfaceLock) {
// TODO: Move from decorator to direct binder-mediated exceptions
// If setRemoteFailure already called, do nothing
if (mInError) return;
mRemoteDevice = new ICameraDeviceUserWrapper(remoteDevice);
IBinder remoteDeviceBinder = remoteDevice.asBinder();
// For legacy camera device, remoteDevice is in the same process, and
// asBinder returns NULL.
if (remoteDeviceBinder != null) {
try {
remoteDeviceBinder.linkToDeath(this, /*flag*/ 0);
} catch (RemoteException e) {
CameraDeviceImpl.this.mDeviceExecutor.execute(mCallOnDisconnected);
throw new CameraAccessException(CameraAccessException.CAMERA_DISCONNECTED,
"The camera device has encountered a serious error");
}
}
// 通知App device 打开
mDeviceExecutor.execute(mCallOnOpened);
mDeviceExecutor.execute(mCallOnUnconfigured);
}
}
- 后面调用到了
CameraService .cpp中的connectDevice方法中去 的connectHelper方法中的makeClient中创建CameraDeviceClient
Status CameraService::makeClient(const sp& cameraService,
const sp& cameraCb, const String16& packageName,
const std::unique_ptr& featureId, const String8& cameraId, int api1CameraId,
int facing, int clientPid, uid_t clientUid, int servicePid, int halVersion,
int deviceVersion, apiLevel effectiveApiLevel,
/*out*/sp* client) {
if (halVersion < 0 || halVersion == deviceVersion) {
// Default path: HAL version is unspecified by caller, create CameraClient
// based on device version reported by the HAL.
switch(deviceVersion) {
case CAMERA_DEVICE_API_VERSION_1_0:
if (effectiveApiLevel == API_1) { // Camera1 API route
sp tmp = static_cast(cameraCb.get());
*client = new CameraClient(cameraService, tmp, packageName, featureId,
api1CameraId, facing, clientPid, clientUid,
getpid());
} else { // Camera2 API route
ALOGW("Camera using old HAL version: %d", deviceVersion);
return STATUS_ERROR_FMT(ERROR_DEPRECATED_HAL,
"Camera device \"%s\" HAL version %d does not support camera2 API",
cameraId.string(), deviceVersion);
}
break;
case CAMERA_DEVICE_API_VERSION_3_0:
case CAMERA_DEVICE_API_VERSION_3_1:
case CAMERA_DEVICE_API_VERSION_3_2:
case CAMERA_DEVICE_API_VERSION_3_3:
case CAMERA_DEVICE_API_VERSION_3_4:
case CAMERA_DEVICE_API_VERSION_3_5:
case CAMERA_DEVICE_API_VERSION_3_6:
if (effectiveApiLevel == API_1) { // Camera1 API route
sp tmp = static_cast(cameraCb.get());
*client = new Camera2Client(cameraService, tmp, packageName, featureId,
cameraId, api1CameraId,
facing, clientPid, clientUid,
servicePid);
} else { // Camera2 API route
sp tmp =
static_cast(cameraCb.get());
*client = new CameraDeviceClient(cameraService, tmp, packageName, featureId,
cameraId, facing, clientPid, clientUid, servicePid);
}
break;
default:
// Should not be reachable
ALOGE("Unknown camera device HAL version: %d", deviceVersion);
return STATUS_ERROR_FMT(ERROR_INVALID_OPERATION,
"Camera device \"%s\" has unknown HAL version %d",
cameraId.string(), deviceVersion);
}
} else {
// A particular HAL version is requested by caller. Create CameraClient
// based on the requested HAL version.
if (deviceVersion > CAMERA_DEVICE_API_VERSION_1_0 &&
halVersion == CAMERA_DEVICE_API_VERSION_1_0) {
// Only support higher HAL version device opened as HAL1.0 device.
sp tmp = static_cast(cameraCb.get());
*client = new CameraClient(cameraService, tmp, packageName, featureId,
api1CameraId, facing, clientPid, clientUid,
servicePid);
} else {
// Other combinations (e.g. HAL3.x open as HAL2.x) are not supported yet.
ALOGE("Invalid camera HAL version %x: HAL %x device can only be"
" opened as HAL %x device", halVersion, deviceVersion,
CAMERA_DEVICE_API_VERSION_1_0);
return STATUS_ERROR_FMT(ERROR_ILLEGAL_ARGUMENT,
"Camera device \"%s\" (HAL version %d) cannot be opened as HAL version %d",
cameraId.string(), deviceVersion, halVersion);
}
}
return Status::ok();
}
结论：
CameraDeviceImpl 就是我们在应用中监听camera打开的监听回调的实例 ，在 StateCallback 的onOpened 回调过来，当调用 deviceImpl.setRemoteDevice(cameraUser)的时候包括我们后续相机的操作具体实现都是在这里
CameraManagerGlobal 是 C++ Framework 层的 CameraService 创建连接，从而创建相机的链路，进行操作CarmDevices