Qt - QWidget: Cannot create a QWidget when no GUI is being used

Question

I'm trying to run a simple Qt program, and when doing so, I get a console window mentioning: QWidget: Cannot create a QWidget when no GUI is being used, and the second line This application has requested the Runtime to terminate....., and the .exe file thus stops working.

My .pro file looks as follows:

#-------------------------------------------------
#
# Project created by QtCreator 2011-04-02T07:38:50
#
#-------------------------------------------------

QT       += core

QT       += gui

TARGET = Hello
CONFIG += console
CONFIG += qt
CONFIG   -= app_bundle

TEMPLATE = app


SOURCES += main.cpp

Any ideas on that?

Thanks.

Answer 1

The problem is not with this .pro; it is most likely in main.cpp. Qt requires you to create a QApplication before creating any QWidget subclasses (as well as certain other classes, such as QPixmap). Your main function should begin with the line:

QApplication app(argc, argv);

and will probably end with a line like:

return app.exec();

In between these calls, you should create and show your main window.

Answer 2

I found that you can do it with a Qt Console project, but ofcourse it will not have the functionality of a console program when you are done with my edits.

First of all you need to exchange #include <QtCoreApplication> with #include <QApplication> in your main.cpp (where you start your application)

In the main(int,char**){

exchange QCoreApplication a(argc, argv); with QApplication a(argc, argv);

and in between QApplication and return a.exec you have your widget and other gui related stuff

and in the end you use return a.exec();}

Answer 3

I think I found where the issue is.

Since I'm using Qt Creator, and when creating a new project, I was choosing Qt Console Application instead of Qt Gui Application.