Why planning scene can't subscribe the new planning scene?

edit

Hi everyone! I am trying to add an object into RVIZ throught C++ interface. I had follow the official tutorial Planning Scene ROS API and failed in step 1....

My Code is follow

moveit_visual_tools::MoveItVisualTools visual_tool("world");
visual_tool.deleteAllMarkers();

ros::Publisher planning_scene_diff_publisher = node_hadle.advertise<moveit_msgs::PlanningScene>("planning_Scene",1);
ros::WallDuration sleep_t(0.5);

while (planning_scene_diff_publisher.getNumSubscribers() < 1)
{
  sleep_t.sleep();
}
visual_tool.prompt("Press 'next' in the RvizVisualToolsGui window to start the demo");

The fixed frame of my robot is "world".

The "Planning Scene Topic" shows in RVIZ is "/move_group/monitored_planning_scene".

After I run my code, I will see the can't break form while (planning_scene_diff_publisher.getNumSubscribers() < 1).

In addition, rqt_graph shows nothing has subscribed from "planning_Scene" which I just creat.