QML Debugger: Unable to listen to port

[krehf]

Hello together,

I'm new to QML and have to work on a project started by a colleague.
This forum has helped me a lot so far, but now I have a big problem and need your help
There are a few bugs in the application and I want to debug it.
When starting the application, I receive the following messages:

QML debugging is enabled. Only use this in a safe environment.
QML Debugger: Unable to listen to port 34567.

Due to that is a ROS project I have to work wich cmake.

System:
Ubuntu 16.04
Qt Creator 4.9.2
QT 5.8.0
ROS Kinetic

Enable QML in the Debugger settings:

CodeSnippets:

CMakeLists.txt:

set(CMAKE_CXX_FLAGS_DEBUG "${CMAKE_CXX_FLAGS_DEBUG} -DQT_QML_DEBUG ")

set(TEMPLATE_QT_VERSION "5.8.0" CACHE STRING "Qt Version")
set(TEMPLATE_QT_MODULES Core Gui Widgets Quick Qml Concurrent Network DBus PrintSupport)

find_package(Qt5 ${TEMPLATE_QT_VERSION} EXACT CONFIG REQUIRED ${TEMPLATE_QT_MODULES})

main.cpp:

  #include <QGuiApplication>

  #include <QQmlDebuggingEnabler>

  #include "ros/ros.h"
  #include "heartbeat/heartbeat.h" 
  #include <string.h>
  #include <iostream>
  #include "message_handler/ros2tag.h"
  #include <QQmlContext>
  #include <QtCore/QDir>
  #include <QtQuick/QQuickView>
  #include <QtQml/QQmlEngine>
  #include <QQmlApplicationEngine>
  #include "imageprovider.h"

  #include "qmlprox.h"
  #include <QtGui/QGuiApplication>
  #include <QtCore/QDir>
  #include <QQmlEngine>

  #include <QList>
  #include <QString>

  #include "geodataprovider.h"
  #include "georeferenceddatalistmodel.h"
  #include "georeferenceddatatriplelistmodel.h"
  #include "parameterdatalistmodel.h"
  #include "parameterdata.h"
  #include "beetImageHandler.h"




  int main(int argc, char **argv)
  {
      QGuiApplication app(argc, argv);

      QQmlDebuggingEnabler enabler;

      //Initialisierung Knoten
      ros::init(argc, argv, "hmi");
      ros::NodeHandle n;

ROS-Launchfile:

<launch>
  <arg name="externParameters" default="0" />
  <group ns="hmi">
    <node name="hmi" pkg="hmi" type="hmi" respawn="true" respawn_delay="10" args="-qmljsdebugger=port:34567" />
  </group>
</launch>

Due to the ROS launch-file the application is started with the argument "-qmljsdebugger=port:34567".

What I've tried until now:

• restart system
• tried several ports
• checked, that no other Qt Application is started

Can anyone of you give me please an hint or a solution for my problem?

Thank you in advance