注意:本页介绍的是 Camera2 软件包。除非您的应用需要 Camera2 的特定低层级功能,否则我们建议您使用 CameraX。CameraX 和 Camera2 都支持 Android 5.0(API 级别 21)及更高版本。
Camera2 提供了一个 Extensions API,用于访问设备制造商在各种 Android 设备上实现的扩展。如需查看支持的扩展模式的列表,请参阅相机扩展。
如需查看支持扩展的设备列表,请参阅支持的设备。
扩展架构
下图显示了相机扩展程序架构。
Camera2 应用可以通过 Camera2 API 使用扩展。Camera2 API 提供了查询可用扩展、配置扩展相机会话以及与相机扩展 OEM 库通信的方法。这样,您的应用就可以使用夜间、HDR、自动、焦外成像或脸部照片修复等扩展程序。
测试相机设备的 Camera2 Extensions API 兼容性
以下代码段会检查设备是否支持 Camera2 Extensions API。并非所有设备都支持扩展,或者设备可能支持一部分扩展。该代码段会返回支持相机扩展的兼容相机 ID 的列表。
Kotlin
private fun getExtensionCameraIds(cameraManager: CameraManager): List<String> = if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.S) { cameraManager.cameraIdList.filter { cameraId -> val characteristics = cameraManager.getCameraCharacteristics(cameraId) val extensionCharacteristics = cameraManager.getCameraExtensionCharacteristics(cameraId) val capabilities = characteristics.get(CameraCharacteristics.REQUEST_AVAILABLE_CAPABILITIES) extensionCharacteristics.supportedExtensions.isNotEmpty() && capabilities?.contains( CameraCharacteristics.REQUEST_AVAILABLE_CAPABILITIES_BACKWARD_COMPATIBLE ) ?: false } } else emptyList()
Java
private List<String> getExtensionCameraIds(CameraManager cameraManager) throws CameraAccessException { if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.S) { return Arrays.stream(cameraManager.getCameraIdList()).filter(cameraId -> { try { CameraCharacteristics characteristics = cameraManager.getCameraCharacteristics(cameraId); CameraExtensionCharacteristics extensionCharacteristics = cameraManager.getCameraExtensionCharacteristics(cameraId); IntStream capabilities = Arrays.stream( characteristics.get( CameraCharacteristics.REQUEST_AVAILABLE_CAPABILITIES ) ); return !extensionCharacteristics.getSupportedExtensions().isEmpty() && capabilities.anyMatch(capability -> capability == CameraCharacteristics .REQUEST_AVAILABLE_CAPABILITIES_BACKWARD_COMPATIBLE ); } catch (CameraAccessException e) { throw new RuntimeException(e); } }).collect(Collectors.toList()); } else { return Collections.emptyList(); } }
使用 Camera2 Extensions API 创建 CameraExtensionSession
在与兼容的设备搭配使用时,Camera2 Extensions API 可让您访问某些相机扩展。以下代码段举例说明了如何创建 CameraExtensionSession
,以便为现有 Camera2 应用使用夜间拍摄模式。
Kotlin
private val captureCallbacks = object : CameraExtensionSession.ExtensionCaptureCallback() { // Implement Capture Callbacks } private val extensionSessionStateCallback = object : CameraExtensionSession.StateCallback() { override fun onConfigured(session: CameraExtensionSession) { cameraExtensionSession = session try { val captureRequest = cameraDevice.createCaptureRequest(CameraDevice.TEMPLATE_PREVIEW).apply { addTarget(previewSurface) }.build() session.setRepeatingRequest( captureRequest, Dispatchers.IO.asExecutor(), captureCallbacks ) } catch (e: CameraAccessException) { Snackbar.make( previewView, "Failed to preview capture request", Snackbar.LENGTH_SHORT ).show() requireActivity().finish() } } override fun onClosed(session: CameraExtensionSession) { super.onClosed(session) cameraDevice.close() } override fun onConfigureFailed(session: CameraExtensionSession) { Snackbar.make( previewView, "Failed to start camera extension preview", Snackbar.LENGTH_SHORT ).show() requireActivity().finish() } } private fun startExtensionSession() { val outputConfig = arrayListOf( OutputConfiguration(stillImageReader.surface), OutputConfiguration(previewSurface) ) val extensionConfiguration = ExtensionSessionConfiguration( CameraExtensionCharacteristics.EXTENSION_NIGHT, outputConfig, Dispatchers.IO.asExecutor(), extensionSessionStateCallback ) cameraDevice.createExtensionSession(extensionConfiguration) }
Java
private CameraExtensionSession.ExtensionCaptureCallback captureCallbacks = new CameraExtensionSession.ExtensionCaptureCallback() { // Implement Capture Callbacks }; private CameraExtensionSession.StateCallback extensionSessionStateCallback = new CameraExtensionSession.StateCallback() { @Override public void onConfigured(@NonNull CameraExtensionSession session) { cameraExtensionSession = session; try { CaptureRequest.Builder captureRequestBuilder = cameraDevice.createCaptureRequest(CameraDevice.TEMPLATE_PREVIEW); captureRequestBuilder.addTarget(previewSurface); CaptureRequest captureRequest = captureRequestBuilder.build(); session.setRepeatingRequest(captureRequest, backgroundExecutor, captureCallbacks); } catch (CameraAccessException e) { Snackbar.make( previewView, "Failed to preview capture request", Snackbar.LENGTH_SHORT ).show(); requireActivity().finish(); } } @Override public void onClosed(@NonNull CameraExtensionSession session) { super.onClosed(session); cameraDevice.close(); } @Override public void onConfigureFailed(@NonNull CameraExtensionSession session) { Snackbar.make( previewView, "Failed to start camera extension preview", Snackbar.LENGTH_SHORT ).show(); requireActivity().finish(); } }; private void startExtensionSession() { ArrayList<OutputConfiguration> outputConfig = new ArrayList<>(); outputConfig.add(new OutputConfiguration(stillImageReader.getSurface())); outputConfig.add(new OutputConfiguration(previewSurface)); ExtensionSessionConfiguration extensionConfiguration = new ExtensionSessionConfiguration( CameraExtensionCharacteristics.EXTENSION_NIGHT, outputConfig, backgroundExecutor, extensionSessionStateCallback ); }
其他资源
如需了解详情,请参阅 CameraExtensionCharacteristics
并查看公开的 Camera2 Extensions API 示例。