camera ndk, how to set camera focus mode

[周青]

.h
#include <NdkCameraCaptureSession.h>
#include <NdkCameraDevice.h>
#include <NdkCameraError.h>
#include <NdkCameraManager.h>
#include <NdkCameraMetadata.h>
#include <NdkCameraMetadataTags.h>
#include <NdkCaptureRequest.h>


I dont know when get a entry by tag how to set.

ACameraMetadata_getConstEntry(mCameraMetadata,
ACAMERA_CONTROL_AF_MODE, &afMode);
ACameraMetadata_getConstEntry(mCameraMetadata,
ACAMERA_CONTROL_AF_AVAILABLE_MODES, &af);