Lost my QApplication

[koahnig]

@astroannie
Hi and welcome to devnet

You do not give enough details. However, it may be your virus checker playing a role. I have had similar cases that I could start my application and the next moment I could not. The executable was gone.

If this is not the case, you need to give some details about your setup and which tutorial you are following.

[astroannie]

Okay, the tutorial is C++ Qt Programming by VoidRealms -- I don't know how to get the nitty-gritty on which Qt I'm using except I downloaded it Tuesday so it's pretty new. (Help > About tells about QtCreator). And yes, I'm running Avast.

It's not my executable -- that one I can fix by logging out and logging back in again. This is an error where it says that it can't open QApplication Here's the code:

#include <QApplication>
#include <QLabel>

int main(int argc, char *argv[])
{
    QApplication app(argc, argv);
    QLabel *label = new QLabel("Hello world");

    label->show();

    return app.exec();
}

... and here's the error:
C:\QtWorkspace\minimal\main.cpp:1: error: C1083: Cannot open include file: 'QApplications': No such file or directory

Is this more helpful?

[mrjj]

Hi
Do you have a project file ?
Its often called a .pro
in that file, you might need
QT += core gui

You can also test by selecting new from menu and create new GUI application.
(just next next it)
Then run it.
If that works, your Qt is fine.

[astroannie]

Sorry, it's QApplication -- no s -- I typed it instead of copy/paste. I learned though -- here's my .pro file

QT += core gui

SOURCES += \
    main.cpp

[mrjj]

ahh. ok. good catch :)

[astroannie]

I told Avast to exclude my workspace. It's still not being able to find the QApplication -- same message. I even tried restarting to no avail.

(I didn't realize you could copy/paste errors -- my old IDE was wonky about that). Here is what it really says, copy/pasted for your convenience:

C:\QtWorkspace\minimal\main.cpp:1: error: C1083: Cannot open include file: 'QApplication': No such file or directory

[koahnig]

@astroannie
You are using Qt creator as your new IDE?
You have the setup from your install process for Qt?

In Qt creator go to menu "Tools" -> "Options" -> "Build&Run" what can you see under the different tabs?
Are there some warnings?

[astroannie]

@koahnig
Okay, I looked.

My compiler is (not copy/pastable) Microsoft Visual C++ 10.0 (x86).

My Qt versions are 5.4.2 and 5.5.1 (both). Would removing one help?

The only thing I have warnings on is Kits -- which I didn't know I even had. They have little triangles with ! in them. One is Qt5.4.2 MSVC2010 OpenGL 32bit and the other is Qt5.5.1 MSVC2010 32-bit (default)

[SGaist]

Hi and welcome to devnet,

You are missing QT += widgets in your .pro file.

With Qt 5, the widgets have moved into their own module.

[astroannie]

Bless you sir, I regret that I can thumb you up but the once.

[SGaist]

No worries for that :)

Since you have it working now, please mark the thread as solved using the "Topic Tool" button so that other forum users may know a solution has been found :)