PyQt Signals for ROS callbacks in RQT Plugin

edit

I answer my own question, showing my solution how to pipe message data via Qt SIGNALS and SLOTS, which hopefully helps others. So after initializing the plugin, I subscibe to a toppic with a custom message type, and in the message callback I just emit a SIGNAL carrying the whole message. In the according SLOT I then update the UI Widgets with the message data. I had to use the most basic PyQt_PyObject as data format to transfer my custom message type.

def __init__(self, context):
    foo()
    bar()
    and_so_on()

    self.sub = rospy.Subscriber('monitoring_result', MyMessageType, self.monitoringCallback,  queue_size=1)
    self.connect(self, SIGNAL("changeUI(PyQt_PyObject)"), self.monitoringSlot)

def monitoringCallback(self, data):
    self.emit(SIGNAL("changeUI(PyQt_PyObject)"), data)

def monitoringSlot(self, data):
    self._widget.lcdGoalID.display(data.current_trajectory + 1)
    self._widget.progressBar.setValue(data.max_num_collisions)
    self._widget.progressBar.setRange(0, data.coll_threshold)

    p = self._widget.palette()
    self._widget.setAutoFillBackground(True);
    if data.severe_collision:
        p.setColor(self._widget.backgroundRole(), Qt.red)
    else:
        p.setColor(self._widget.backgroundRole(), Qt.green)
    self._widget.setPalette(p)