Problem showing camera stream in Viz

[rfan121]

my ROS master works fine with joystick to command the robot. but when i want to stream my webcam view in Viz, isn’t showing at all. when i use my master to show my webcam view in RVIZ is works fine. please help ke solve this problem. thanks.

[nicostudt]

Make sure to setup the ROS environment parameter correctly.
You may confirm that the communication works in both directions by using another widget. Also make sure to subscribe to the correct topic name and type.

[rfan121]

i already set the ROS environment parameter correctly. if not, joystick widget can’t control the robot, right? another widget except joystick not subscribe the topic with correct topic name and type.

[Jie-fafa]

same error ，both debug widget and camera widget can not work

[yin-yu-yu]

Setting the ROS_IP environment variable to the robot's actual IP address solved all the issues. The camera, lidar, and map topics immediately started publishing data .

On the robot (where roscore is running), add the following to your ~/.bashrc or run it in the terminal before launching your nodes:

export ROS_IP=192.168.10.23
export ROS_MASTER_URI=http://192.168.10.23:11311

Important: Replace 192.168.10.23 with your robot's actual IP address .

Why It Works
In a ROS network, nodes need to be able to connect directly to each other's IP addresses to exchange data. Without ROS_IP set correctly, nodes fall back to using the hostname, which may not be resolvable in your network (especially when using Wi-Fi or a mobile hotspot). This prevents the underlying TCP connections from being established, causing rostopic list to show the topics, but rostopic echo to return nothing