error: 'QMainWindow' file not found #include <QMainWindow> ^

AnnieChen

Hi,

I'm using Qt.5.70 version and macOS 10.12.

I have an exist project that is created as C++ project. Then i find out that I need GUI, so I add New Qt Designer Form Class to create a GUI.

But when I try to build, there is an error:

/Users/zhijunchen/Dropbox/Wholesale-Clud/src/Wholesale-Club/mainwindow.h:8: error: 'QMainWindow' file not found
#include <QMainWindow>
^

I have these in my .pro file already:

QT += core gui

greaterThan(QT_MAJOR_VERSION, 4): QT += widgets

but still not working.

Can anyone help me please?
Thank you!
Annie

m.sue

Hi,
maybe you just need to re-run qmake.
-Michael.

mostefa

I think that you need to add also widgets module in your .pro file

QT += widgets

If this not work for you , can tell us which qt version are you using?