Cannot open include file error

KunLin

Hi

I'm a new Qt user and I've encountered a problem of using custom widget. Here is the description. Can anyone please help me out?

I'm using VS2013 with Qt5 Addin.

I created a MyOpenGLWidget inherits QOpenGLWidget in a DLL called UiWidgets that I created. The uic and moc and compilation worked fine.

Then I want to use this widget in my other project MyApp. I designed the interface in QtDesigner and added the MyOpenGLWidget. I promoted the QOpenGLWidget in QtDesigner to MyOpenGLWidget and set the header file to "../UiWIdgets/MyOpenGLWidget.h" (Since both the projects exists under the same solution directory, it should work)

But, after I coded the MyApp class and try to compile it, I got the following error.

1> Uic'ing MyApp.ui...
1> MyApp.cpp
1>c:\dev\projects\MyProject\MyApp\../UiWidgets/MyOpenGLWidget.h(18): fatal error C1083: Cannot open include file: 'ui_MyOpenGLWidget.h': No such file or directory
1> moc_MyApp.cpp
1>c:\dev\projects\MyProject\MyApp\../UiWidgets/MyOpenGLWidget.h(18): fatal error C1083: Cannot open include file: 'ui_MyOpenGLWidget.h': No such file or directory
1> main.cpp
1>c:\dev\projects\MyProject\MyApp\../UiWidgets/MyOpenGLWidget.h(18): fatal error C1083: Cannot open include file: 'ui_MyOpenGLWidget.h': No such file or directory
1> Generating Code...

My question is:

The path is fine (I checked in the command line). Why is the error, did I miss somethin important?
Is there a better practice to do so?

koahnig

Hi and welcome to devnet

Does file "ui_MyOpenGLWidget.h" exist and where?

It looks to me like you have a path issue and "ui_MyOpenGLWidget.h" is somewhere located, but not in a folder of the path.

KunLin

@koahnig Thank you for replying. The file is located at ProjectDir/GeneratedFiles/ui_MyOpenGLWidget.h. I wonder wouldn't it be enough to specify the path of only MyOpenGLWidget.h other than ui_MyOpenGLWidget.h? Since ui_XXX.h is generated by uic?

koahnig

@KunLin

If you have only one projectdir I am agreeing, but I understood that you may have two.
When you setup a dll project all will be consistent within this project for compilation and linking. Typically the ui_*.h files are generated in a build folder. However, your project setup will know about it.
If you try to use the same header in another project (in your case MyOpenGLWidget.h), but the associated ui-file (in your case ui_MyOpenGLWidget.h) is not in the same folder, your project setup cannot know.

KunLin

@koahnig

Thank you. That makes sense. So do you have any advice about how to use a custom widget in DLL? And after I modified this include in MyOpenGLWidget.h

#include "ui_MyOpenGLWidget.h"

to

#include "GeneratedFiles/ui_MyOpenGLWidget.h"

and it complies and runs like charm. And indeed I added ".\GeneratedFiles" in my additional include directories.

But I still do not know the reason.

koahnig

I am not using setups similar to yours. Therefore my advise might be wrong.

Anyway, I assume you have a dll project with follwoing structure:

dllProject with MyOpenGLWidget.h
dllProject/GeneratedFiles with ui_MyOpenGLWidget.h

and

ProjectDir with your new project files
ProjectDir/GeneratedFiles with some generated files for the new project

Since ProjectDir is your current project directory ./GeneratedFiles will point to ProjectDir/GeneratedFiles

Your INCLUDEPATH will hold at least dllProject ProjectDir/GeneratedFiles
you probably should add dllProject/GeneratedFiles
and you should be fine.

One note: You seem to use the backward slash '\' as it is tradition under windows. However, nowadays windows does also accept a foward slash '/'. I would recomment to use in general the linux compatible '/' also for any folder handling within Qt related files. Sometimes this may help you to prevent severe difficulties.

KunLin

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