Problem of including Widgets into DLL

[dsedov]

Hi. I am writing a software using VS2008 and QT4.3.3 with VS integration and it's structure is following:

First project is an application
Second project is a Qt Library project which produces a DLL. Now the problem I am having is that when I include DLL header file into my application compiled can't find auto generated ui_***.h file.

How should I go about including several widgets that I plan to use into a single DLL and be able to use QT Designer. If I were to write a widget from scratch without using .ui files - everything works. But the problem is that DLL compiles just fine, but the actual application, when includes DLL header (which also includes auto generated ui_***.h files) does not find those auto generated headers.

Maybe there is some other way to write a single DLL projects which includes several widgets?

[janEUcitzen]

HI.

I have done something the same as you do...but I made an _impl class which inluded the ui file.

the actual dll interface is defined as an interface class I have totally defined (just calls to the _impl class)...in this way I can control which elements in the widget(s) can be accessed externally.

rgds
Jan

[dsedov]

I am not sure what you mean by _impl class. Could you explain a little more. I am not a big C++ pro =(

[janEUcitzen]

I always make the dll's with one interface class.

e.g.

dll_mywidget.hpp
dll_mywidget.cpp

the class dll_mywidget are just call to another class dll_mywidget_impl

The dll_mywidget_impl class is the one that include the ui file...basically you make dll_mywidget_impl as you would make a normal widget....

and in dll_mywidget.cpp you decide which parts to make public in the dll...dont forget the class you want to make public in the dll, needs special DLL declaration (DLL_EXPORT) in order to work.

jan

[dsedov]

LOL I still don't get it. I think the way I understand it is that I have a dummy class which gets included into the main application and it exports other class with UI. But how do I include the base class into main application without ui header?

So far I have this:

Here the dummy class which includes the interface class (test.h) :

#ifndef FBL_GUI_H
#define FBL_GUI_H
 
#include "fbl_gui_global.h"
#include "test.h"
class FBL_GUI_EXPORT fbl_gui
{
public:
	fbl_gui();
	~fbl_gui();
 
private:
 
};
 
#endif // FBL_GUI_H

#ifndef FBL_GUI_H
#define FBL_GUI_H

#include "fbl_gui_global.h"
#include "test.h"
class FBL_GUI_EXPORT fbl_gui
{
public:
	fbl_gui();
	~fbl_gui();

private:

};

#endif // FBL_GUI_H

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Then I have an interface class in the same dll project:

#ifndef TEST_H
#define TEST_H
 
#include <QWidget>
#include "ui_test.h"
 
class test : public QWidget
{
	Q_OBJECT
 
public:
	test(QWidget *parent = 0);
	~test();
 
private:
	Ui::testClass ui;
};
 
#endif // TEST_H

#ifndef TEST_H
#define TEST_H

#include <QWidget>
#include "ui_test.h"

class test : public QWidget
{
	Q_OBJECT

public:
	test(QWidget *parent = 0);
	~test();

private:
	Ui::testClass ui;
};

#endif // TEST_H

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Now the problem is that if I include the base dll class it also includes the widget class. How can I skip this part but be able to access the widget and be able to create it in the main app?

[spirit]

Hi. I am writing a software using VS2008 and QT4.3.3 with VS integration and it's structure is following:

First project is an application
Second project is a Qt Library project which produces a DLL. Now the problem I am having is that when I include DLL header file into my application compiled can't find auto generated ui_***.h file.

How should I go about including several widgets that I plan to use into a single DLL and be able to use QT Designer. If I were to write a widget from scratch without using .ui files - everything works. But the problem is that DLL compiles just fine, but the actual application, when includes DLL header (which also includes auto generated ui_***.h files) does not find those auto generated headers.

Maybe there is some other way to write a single DLL projects which includes several widgets?

at the first you need to create h-file with the following content (e.g. myglobal.h)

#ifndef MYGLOBAL_H
#define MYGLOBAL_H
 
#include <QtGlobal>
 
#ifdef MY_LIB_STATICLIB 
#  undef MY_LIB_SHAREDLIB 
#  define MY_LIB_EXPORT 
#else 
#  ifdef MY_LIB_MAKEDLL 
#   define MY_LIB_EXPORT Q_DECL_EXPORT 
#  else 
#   define MY_LIB_EXPORT Q_DECL_IMPORT 
#  endif
#endif
 
#endif//MYGLOBAL_H

#ifndef MYGLOBAL_H
#define MYGLOBAL_H

#include <QtGlobal>

#ifdef MY_LIB_STATICLIB 
#  undef MY_LIB_SHAREDLIB 
#  define MY_LIB_EXPORT 
#else 
#  ifdef MY_LIB_MAKEDLL 
#   define MY_LIB_EXPORT Q_DECL_EXPORT 
#  else 
#   define MY_LIB_EXPORT Q_DECL_IMPORT 
#  endif
#endif

#endif//MYGLOBAL_H

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then in pro-file of your lib you should add next thing

...
contains(CONFIG, staticlib) { 
	DEFINES += MY_LIB_STATICLIB 
} else { 
	DEFINES += MY_LIB_SHAREDLIB 
}
 
win32 { 
	DEFINES += MY_LIB_MAKEDLL 
}
...

...
contains(CONFIG, staticlib) { 
	DEFINES += MY_LIB_STATICLIB 
} else { 
	DEFINES += MY_LIB_SHAREDLIB 
}

win32 { 
	DEFINES += MY_LIB_MAKEDLL 
}
...

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and then you must add MY_LIB_EXPORT before class name which you want to export

#include "myglobal.h"
class MY_LIB_EXPORT MyObj
{
...
};

#include "myglobal.h"
class MY_LIB_EXPORT MyObj
{
...
};

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[dsedov]

Yeah I know that. Thanks. The problem is that when I include DLL header in a main app it won't be able to find autogenerated files from QT Designer. Dll compiles just fine, but when main app compiles it sais : fatal error C1083: Cannot open include file: 'ui_test.h': No such file or directory

[spirit]

could you show us pro-file of app not lib?

[dsedov]

Err.. there is no .pro file. I am using VS2008 with QT integration.

[spirit]

ok. what do you try to do now: build a lib or build app with the lib which you are created?

[dsedov]

Build an app.
The lib compiles just fine. I just have problem of my app using lib headers as it cannot find autogenerated ui_***.h files.

My app has this in a header:

#include "../fbl_gui/fbl_gui.h"

#include "../fbl_gui/fbl_gui.h"

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This includes library header, so I will be able to use it's objects.

[dsedov]

So any ideas???

[spirit]

look at this example