unable to open any package with QT creator

[Kunal]

I am using Ubuntu 14.04, ROS indigo, Qt Creator 3.0.1

when I try to open any catkin package in the workspace, following error pops up every time.

CMake Error at CMakeLists.txt:7 (find_package):
By not providing "Findcatkin.cmake" in CMAKE_MODULE_PATH this project has
asked CMake to find a package configuration file provided by "catkin", but
CMake did not find one.

Could not find a package configuration file provided by "catkin" with any
of the following names:

catkinConfig.cmake
catkin-config.cmake

Add the installation prefix of "catkin" to CMAKE_PREFIX_PATH or set
"catkin_DIR" to a directory containing one of the above files. If "catkin"
provides a separate development package or SDK, be sure it has been
installed.
-- Configuring incomplete, errors occurred!
See also "/home/kk/catkin_ws_navigation/build/nav2d_exploration/CMakeFiles/CMakeOutput.log".

I am trying to open Navigation_2d package present [here] (https://github.com/skasperski/navigation_2d/tree/indigo) .All the packages are successfully built in the build directory. Can anyone please help me out I am totally stuck