1. Qtcreator 4.5.1 update Ubuntun 18.04
In Ubuntu 18.04 there's no need to replace the symbolic link. Also it seems this version is consuming a lot less resources.
1. Qtcreator
Qtcreator is a great IDE especially for C++ and ROS. I find it easier to manage than eclipse and better than Kdevelop. To get it up and running:
First don't forget to open Qtcreator from a sourced terminal and select the uppermost CMakeLists.txt as the project (not the CMakeLists.txt associated with each package). Then select the correct build folder from the browse option. This should let you compile directly in Qtcreator
catkin_init_workspace creates a CMakeLists.txt which is actually a symbolic link towards pointing towards the toplevel cmake. For Qtcreator to work this needs to be replaced, with the following command
rm CMakeLists.txt ; cp /opt/ros/indigo/share/catkin/cmake/toplevel.cmake ./CMakeLists.txt
If the repository uses catkin build instead of catkin_make things aren't so easy as there is no toplevel CMakeLists.txt file. A workaround
The CMakelists.txt file in the package must be selected as project, e.g. catkin_ws/src/packageA/CMakeLists.txt
The build folder must be selected as the catkin build folder e.g. catkin_ws/build/packageA/
You should be able to compile using qt at this stage. It should be noted that every time you add a new file catkin build must be executed
The default qtcreator 3.5.1 in the repo's fo ubuntu 16 is extremely buggy, but so far the lastest version available for download works fine