CMake error while integrating catkin workspace with qtCreator

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Hi all,

I am trying to open a ros package in Qt Creator following http://wiki.ros.org/IDEs . In Qtcreator, I opened the CmakeLists.txt file from ~/catkin_ws/src and changed the build directory properly to ~/catkin_ws/build and then ran cmake. I am following this answer.

Also, I set the cmake arguments for devel and install directories properly which are inside catkin_ws using this line

-DCMAKE_INSTALL_PREFIX=/home/sharath/catkin_ws/install
-DCATKIN_DEVEL_PREFIX=/home/sharath/catkin_ws/devel

But when I run cmake in qtCreator, I get the following error:

CMake Error at /opt/ros/indigo/share/catkin/cmake/safe_execute_process.cmake:11 (message):
execute_process(/usr/bin/python
"/home/sharath/catkin_ws/build/catkin_generated/generate_cached_setup.py")
returned error code 1
Call Stack (most recent call first):
/opt/ros/indigo/share/catkin/cmake/all.cmake:186 (safe_execute_process)
/opt/ros/indigo/share/catkin/cmake/catkinConfig.cmake:20 (include)
CMakeLists.txt:52 (find_package)
File "/home/sharath/catkin_ws/build/catkin_generated/generate_cached_setup.py", line 20, in <module>
from catkin.environment_cache import generate_environment_script
ImportError: No module named catkin.environment_cache
Traceback (most recent call last):
-- Using CATKIN_DEVEL_PREFIX: /home/sharath/catkin_ws/devel
-- Using CMAKE_PREFIX_PATH:
-- Using PYTHON_EXECUTABLE: /usr/bin/python
-- Using Debian Python package layout
-- Using empy: /usr/bin/empy
-- Using CATKIN_ENABLE_TESTING: ON
-- Call enable_testing()
-- Using CATKIN_TEST_RESULTS_DIR: /home/sharath/catkin_ws/build/test_results
-- Found gtest sources under '/usr/src/gtest': gtests will be built
-- Using Python nosetests: /usr/bin/nosetests-2.7
-- catkin 0.6.14
-- Configuring incomplete, errors occurred!
See also "/home/sharath/catkin_ws/build/CMakeFiles/CMakeOutput.log".
See also "/home/sharath/catkin_ws/build/CMakeFiles/CMakeError.log".

Here are the problems I am facing,

1) First of all , the above error appears . I tried updating the python modules by sudo pip install -U catkin_pkg but that does not help.

2) Also interestingly after running the cmake in qtcreator , my catkin_make doesn't run in the ~/catkin_ws

Now I cannot use ros aliases like roscore and stuff even though I have already sourced catkin_ws/devel/setup.bash and also /opt/ros/indigo/setup.bash in my bashrc. Restarted the terminal , but still catkin_make and aliases dont run. However this gets solved the moment I source again inside terminal for /opt/ros/indigo/setup.bash. This solves and now all ros commands work normally without sourcing only until I run Cmake from qtcreator and then ros commands dont work and need to be sourced again from terminal. Is the setup.bash in catkin_ws/devel getting modified or something ?

3) However my main problem is how to solve the qt creator error above.?

I tried setting up the workspace again but these problems recur in the same manner. There's something I am missing.

Update:
Thanks @Simon for the answer! I tried the "old_way" mentioned in the answer and replaced the CMakeLists.txt in the ~/catkin_ws/src/ with the file it links to. Then, I opened that CMakefile in qtcreator and specified build directory as ~/catkin_ws/build/ and then ran cmake and then, I get the same error as mentioned above. Now, when I run catkin_make ...
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