Problem in Setting up QT to Integrate with OpenCV and C++ in Ubuntu 18.04 using CMake

[ferdnyc (FeRD (Frank Dana))]

@raisa

I read about explicit path definition for Qt integration instead of just putting " WITH_QT=ON ". So I decided to go with cmake-gui and defined each path for Qt path configuration. Like this :

WITH_QT=ON (checked in cmake-gui)
Qt5Concurrent_DIR = /home/raisa/Qt5.9.9/5.9.9/gcc_64/lib/cmake/Qt5Concurrent
Qt5Core_DIR       = /home/raisa/Qt5.9.9/5.9.9/gcc_64/lib/cmake/Qt5Core
Qt5Gui_DIR        = /home/raisa/Qt5.9.9/5.9.9/gcc_64/lib/cmake/Qt5Gui
Qt5OpenGL_DIR     = /home/raisa/Qt5.9.9/5.9.9/gcc_64/lib/cmake/Qt5OpenGL
Qt5Test_DIR       = /home/raisa/Qt5.9.9/5.9.9/gcc_64/lib/cmake/Qt5Test
Qt5Widgets_DIR    = /home/raisa/Qt5.9.9/5.9.9/gcc_64/lib/cmake/Qt5Widgets
Qt5_DIR           = /home/raisa/Qt5.9.9/5.9.9/gcc_64/lib/cmake/Qt5

Also, those seem wrong to me. Those aren’t the locations of the Qt components, they’re the locations of the CMake configuration files that configure the Qt components — but they’ll be thrown off with those paths (if they’re even run at all). The right variables would be something like…

Qt5Concurrent_DIR = /home/raisa/Qt5.9.9/5.9.9/

or…

Qt5Core_DIR       = /home/raisa/Qt5.9.9/5.9.9/gcc_64/

(Most likely the same path for all of the components, since they’re all ultimately installed in the same dir.)

But you shouldn’t need to do that, if CMake is in charge, and if you’re using a system Qt (installed by sudo apt). CMake will pick up the pieces for those automatically, they’re in default locations. (As long as you have -dev packages installed.)

If things aren’t working, it’s best to post as much of your actual CMakeLists.txt contents as could be relevant, from tiny snippets it’s hard to say what could be an issue. Posting actual output of the cmake generation run also helps.