I found the problem.
The problem is that I update labels in show_gaze_information.
This function is a callback that is called when a message is published on the topic.
To correct the code, in function show_gaze_information, the message should be stored in a variable. Nothing should be modified in UI.
Then in main body of code, I added this part:# update gaze infor periodically timer_gaze = QtCore.QTimer() timer_gaze.timeout.connect(update_gaze_information) timer_gaze.setInterval(500) timer_gaze.start()
This code periodically calls update_gaze_information every 0.5 seconds. Now, in this function, I update labels in the UI.