手电筒相机2 API

Android Camera2 API 中可以同时使用相机预览和手电筒吗？

当我尝试使用时CameraManager.setTorchMode(String cameraId, boolean enabled)当相机未打开时它工作正常。但是当相机打开时我尝试setTorchMode我收到这个异常：

CameraService: setTorchMode: 相机 0 的手电筒模式不可用，因为相机正在使用中

设置 FLASH_MODE 和 AE_MODE 很重要。下面是工作代码：

public void toggleFlashMode(boolean enable){
try {
            if (mCameraType.equals(CameraType.BACK)) {
                if (enable) {
                    mPreviewRequestBuilder.set(CaptureRequest.FLASH_MODE, CaptureRequest.FLASH_MODE_TORCH);
                    mPreviewRequestBuilder.set(CaptureRequest.CONTROL_AE_MODE, CaptureRequest.CONTROL_AE_MODE_ON);
                } else {
                    mPreviewRequestBuilder.set(CaptureRequest.FLASH_MODE, CaptureRequest.FLASH_MODE_OFF);
                    mPreviewRequestBuilder.set(CaptureRequest.CONTROL_AE_MODE, CaptureRequest.CONTROL_AE_MODE_OFF);
                }
                mCaptureSession.setRepeatingRequest(mPreviewRequestBuilder.build(), null, null);
            }
        } catch (CameraAccessException e) {
            e.printStackTrace();
        }
}