@SuppressWarnings("static-access")
  @Override
  public void surfaceCreated(SurfaceHolder holder) {
    // initialize the camera
    mCamera = Camera.open();

    // parameters : set picture size
    mParameters = mCamera.getParameters();

    // flash off
    if (mCheckResult.getFlashMode() != null) {
      mParameters.setFlashMode(mParameters.FLASH_MODE_OFF);
    }

    mCamera.setParameters(mParameters);

    // start the preview on surface
    previewCamera();
  }