code: public void handleCameraPreviewTouchEvent(MotionEvent ev) {
          if (mFullScreen != null) mFullScreen.handleTouchEvent(ev);
          if (mDisplayRenderer != null) mDisplayRenderer.handleTouchEvent(ev);
      }
docs: Notify the preview and encoder programs
  of a touch event. Used by
  GLCameraEncoderView
  
  @param ev onTouchEvent event to handle