subclassing MainForm class

**mickey** · 4th March 2006, 11:56

Hi,
I'm subclassing MainForm class (create from qtDesigner). I code insert new mymainform.cpp e mymainform.h. and seems ok. But when I create an instance of it in main.cpp, linker get these errors:

Qt Code:

Switch view

Editor error LNK2001: unresolved external symbol "public: virtual bool __thiscall myMainForm::qt_emit(int,struct QUObject *)" (?qt_emit@myMainForm@@UAE_NHPAUQUObject@@@Z)
Editor error LNK2001: unresolved external symbol "public: virtual bool __thiscall myMainForm::qt_invoke(int,struct QUObject *)" (?qt_invoke@myMainForm@@UAE_NHPAUQUObject@@@Z)
Editor error LNK2001: unresolved external symbol "public: virtual bool __thiscall myMainForm::qt_property(int,int,class QVariant *)" (?qt_property@myMainForm@@UAE_NHHPAVQVariant@@@Z)
Editor error LNK2001: unresolved external symbol "public: virtual char const * __thiscall myMainForm::className(void)const " (?className@myMainForm@@UBEPBDXZ)
Editor error LNK2001: unresolved external symbol "public: virtual void * __thiscall myMainForm::qt_cast(char const *)" (?qt_cast@myMainForm@@UAEPAXPBD@Z)
Editor error LNK2019: unresolved external symbol "public: static class QMetaObject * __cdecl myMainForm::staticMetaObject(void)" (?staticMetaObject@myMainForm@@SAPAVQMetaObject@@XZ) referenced in function "public: virtual class QMetaObject * __thiscall myMainForm::metaObject(void)const " (?metaObject@myMainForm@@UBEPAVQMetaObject@@XZ)
Editor fatal error LNK1120: 6 unresolved externals

Editor error LNK2001: unresolved external symbol "public: virtual bool __thiscall myMainForm::qt_emit(int,struct QUObject *)" (?qt_emit@myMainForm@@UAE_NHPAUQUObject@@@Z)
Editor error LNK2001: unresolved external symbol "public: virtual bool __thiscall myMainForm::qt_invoke(int,struct QUObject *)" (?qt_invoke@myMainForm@@UAE_NHPAUQUObject@@@Z)
Editor error LNK2001: unresolved external symbol "public: virtual bool __thiscall myMainForm::qt_property(int,int,class QVariant *)" (?qt_property@myMainForm@@UAE_NHHPAVQVariant@@@Z)
Editor error LNK2001: unresolved external symbol "public: virtual char const * __thiscall myMainForm::className(void)const " (?className@myMainForm@@UBEPBDXZ)
Editor error LNK2001: unresolved external symbol "public: virtual void * __thiscall myMainForm::qt_cast(char const *)" (?qt_cast@myMainForm@@UAEPAXPBD@Z)
Editor error LNK2019: unresolved external symbol "public: static class QMetaObject * __cdecl myMainForm::staticMetaObject(void)" (?staticMetaObject@myMainForm@@SAPAVQMetaObject@@XZ) referenced in function "public: virtual class QMetaObject * __thiscall myMainForm::metaObject(void)const " (?metaObject@myMainForm@@UBEPAVQMetaObject@@XZ)
Editor fatal error LNK1120: 6 unresolved externals

To copy to clipboard, switch view to plain text mode

Qt Code:

Switch view

//mymainform.h
#include "mainform.h"
#include "mywidget.h"
class myMainForm : public MainForm
{
    Q_OBJECT
 
public:
    myMainForm( QWidget* parent = 0, const char* name = 0, WFlags fl = WType_TopLevel );
    ~myMainForm();	
	MyWidget top;
};

//mymainform.h
#include "mainform.h"
#include "mywidget.h"
class myMainForm : public MainForm
{
    Q_OBJECT

public:
    myMainForm( QWidget* parent = 0, const char* name = 0, WFlags fl = WType_TopLevel );
    ~myMainForm();	
	MyWidget top;
};

To copy to clipboard, switch view to plain text mode

Qt Code:

Switch view

//mymainform.cpp
#include "mymainform.h"
myMainForm::myMainForm( QWidget* parent, const char* name, WFlags fl )
    : MainForm( parent, name, fl )
{
}
 
myMainForm::~myMainForm()
{ 
}

//mymainform.cpp
#include "mymainform.h"
myMainForm::myMainForm( QWidget* parent, const char* name, WFlags fl )
    : MainForm( parent, name, fl )
{
}

myMainForm::~myMainForm()
{ 
}

To copy to clipboard, switch view to plain text mode

Qt Code:

Switch view

//main.cpp
#include "mymainform.h"
..........
//MainForm w;
myMainForm w;
w.resize(600,500);
a.setMainWidget(&w);
w.show();
a.connect( &a, SIGNAL( lastWindowClosed() ), &a, SLOT( quit() ) );
return a.exec();

//main.cpp
#include "mymainform.h"
..........
//MainForm w;
myMainForm w;
w.resize(600,500);
a.setMainWidget(&w);
w.show();
a.connect( &a, SIGNAL( lastWindowClosed() ), &a, SLOT( quit() ) );
return a.exec();

To copy to clipboard, switch view to plain text mode

What happen?

**jacek** · 4th March 2006, 11:58

Did you rerun qmake after you have added Q_OBJECT to myMainForm class?

**mickey** · 4th March 2006, 14:33

No, but there are still errors (after nmake clean;qmake;nmake)

Qt Code:

Switch view

LINK : warning LNK4199: /DELAYLOAD:comdlg32.dll ignored; no imports found from comdlg32.dll
LINK : warning LNK4199: /DELAYLOAD:oleaut32.dll ignored; no imports found from oleaut32.dll
LINK : warning LNK4199: /DELAYLOAD:winmm.dll ignored; no imports found from winmm.dll
LINK : warning LNK4199: /DELAYLOAD:wsock32.dll ignored; no imports found from wsock32.dll
LINK : warning LNK4199: /DELAYLOAD:winspool.dll ignored; no imports found from winspool.dll
main.obj : error LNK2019: unresolved external symbol "public: virtual __thiscall myMainForm::~myMainForm(void)" (??1myMainForm@@UAE@XZ) referenced in
function _main
main.obj : error LNK2019: unresolved external symbol "public: __thiscall myMainForm::myMainForm(class QWidget *,char const *,unsigned int)" (??0myMain
Form@@QAE@PAVQWidget@@PBDI@Z) referenced in function _main
Editor.exe : fatal error LNK1120: 2 unresolved externals
NMAKE : fatal error U1077: 'link' : return code '0x460'
Stop.

LINK : warning LNK4199: /DELAYLOAD:comdlg32.dll ignored; no imports found from comdlg32.dll
LINK : warning LNK4199: /DELAYLOAD:oleaut32.dll ignored; no imports found from oleaut32.dll
LINK : warning LNK4199: /DELAYLOAD:winmm.dll ignored; no imports found from winmm.dll
LINK : warning LNK4199: /DELAYLOAD:wsock32.dll ignored; no imports found from wsock32.dll
LINK : warning LNK4199: /DELAYLOAD:winspool.dll ignored; no imports found from winspool.dll
main.obj : error LNK2019: unresolved external symbol "public: virtual __thiscall myMainForm::~myMainForm(void)" (??1myMainForm@@UAE@XZ) referenced in
function _main
main.obj : error LNK2019: unresolved external symbol "public: __thiscall myMainForm::myMainForm(class QWidget *,char const *,unsigned int)" (??0myMain
Form@@QAE@PAVQWidget@@PBDI@Z) referenced in function _main
Editor.exe : fatal error LNK1120: 2 unresolved externals
NMAKE : fatal error U1077: 'link' : return code '0x460'
Stop.

To copy to clipboard, switch view to plain text mode

**wysota** · 4th March 2006, 14:39

Check if you have mymainform.cpp mentioned in SOURCES section of your project file. Add it if it's not there and rerun qmake afterwards.

**mickey** · 4th March 2006, 14:48

Thanks you; yes it was .pro

//mywidget.cpp

Qt Code:

Switch view

connect(this, SIGNAL(myUpdate()), w ,SLOT(updateWidgets()) );

connect(this, SIGNAL(myUpdate()), w ,SLOT(updateWidgets()) );

To copy to clipboard, switch view to plain text mode

w is MainForm* w; and updateWidget() a SLOT in MainForm class...

appear a message saying: "no such SLOT" sender and receiver unamed"

This is the first time I subclassing MainForm created fom QTDesigner. I change only the code You see above and seems works properly! Are there to doother changes?
Thanks

**mickey** · 4th March 2006, 15:28

I resolve it changing MyWidget declaration to pointer (below coded)

Qt Code:

Switch view

class myMainForm : public MainForm
{
    Q_OBJECT
 
public:
    myMainForm( QWidget* parent = 0, const char* name = 0, WFlags fl = WType_TopLevel );
    ~myMainForm();
	void init();
        //MyWidget top
	MyWidget* top;
};

class myMainForm : public MainForm
{
    Q_OBJECT

public:
    myMainForm( QWidget* parent = 0, const char* name = 0, WFlags fl = WType_TopLevel );
    ~myMainForm();
	void init();
        //MyWidget top
	MyWidget* top;
};

To copy to clipboard, switch view to plain text mode

But now my problem don't chage. I do it for to do this:

Qt Code:

Switch view

myMainForm::myMainForm( QWidget* parent, const char* name, WFlags fl )
    : MainForm( parent, name, fl )
{
	printf("myMainformt\n");
	*top = MyWidget(this, "top shared", this->myWidget1);
	this->WidgetStack->addWidget(top);
}

myMainForm::myMainForm( QWidget* parent, const char* name, WFlags fl )
    : MainForm( parent, name, fl )
{
	printf("myMainformt\n");
	*top = MyWidget(this, "top shared", this->myWidget1);
	this->WidgetStack->addWidget(top);
}

To copy to clipboard, switch view to plain text mode

This two istruction cause some 'debug error' when I launch app....
The same if I code these two in main.cpp

**mickey** · 5th March 2006, 16:47

Nothing hints for this last problem, please?

**jacek** · 5th March 2006, 17:11

Originally Posted by mickey

*top = MyWidget(this, "top shared", this->myWidget1);

You can't copy widgets --- try:

Qt Code:

Switch view

top = new MyWidget(this, "top shared", this->myWidget1);

top = new MyWidget(this, "top shared", this->myWidget1);

To copy to clipboard, switch view to plain text mode

**mickey** · 5th March 2006, 21:15

It seems ok;
I have a problem. In mywidget.cpp constructor I have:

Qt Code:

Switch view

connect(this, SIGNAL(myUpdate()), w, SLOT(myUpdateWidgets()) );

connect(this, SIGNAL(myUpdate()), w, SLOT(myUpdateWidgets()) );

To copy to clipboard, switch view to plain text mode

in main.cpp:

Qt Code:

Switch view

myMainForm w; a.setMainWidget(&w);....

myMainForm w; a.setMainWidget(&w);....

To copy to clipboard, switch view to plain text mode

When I launch app appear this message:

Qt Code:

Switch view

QObject::connect: No such slot MainForm::myUpdateWidgets()
QObject::connect:  (sender name:   'myWidget1')
QObject::connect:  (receiver name: 'MainForm')

QObject::connect: No such slot MainForm::myUpdateWidgets()
QObject::connect:  (sender name:   'myWidget1')
QObject::connect:  (receiver name: 'MainForm')

To copy to clipboard, switch view to plain text mode

myUpdateWidgets() is a SLOT of myMainForm! And not MainForm (base class)
Why doesn't it work? Thanks

**jacek** · 5th March 2006, 21:37

How did you declare that slot? Could you also post the .pro file?

**mickey** · 5th March 2006, 23:54

Hi, the error message above is at runtime (in console).
I saw now the problem is in other place...

Qt Code:

Switch view

//myWidget.h
class MyWidget {
    MainForm* w;

//myWidget.h
class MyWidget {
    MainForm* w;

To copy to clipboard, switch view to plain text mode

}
When I use in costructor of MyWidget: "connect(this, SIGNAL(myUpdate()), w, SLOT(myUpdateWidgets()) );" w pointer refers to MainForm;
But if I change in 'myMainForm* w' (in mywidget.h), compiler says me 'class redefinition error....' (error refers to line "class myMainForm {...." in mymainform.h)
I need a pointer to myMainForm class from MyWidget class (as It was for MainForm..)
Thanks

**jacek** · 6th March 2006, 00:18

Originally Posted by mickey

But if I change in 'myMainForm* w' (in mywidget.h), compiler says me 'class redefinition error....' (error refers to line "class myMainForm {...." in mymainform.h)

Could you at least learn to post exact error messages?

I need a pointer to myMainForm class from MyWidget class (as It was for MainForm..)

If you need that pointer only to make the connection, then make this connection in a different place (where you have both pointers).

Thread: subclassing MainForm class

Thread Tools

Search Thread

Display

Hybrid View

subclassing MainForm class

Re: subclassing MainForm class

Re: subclassing MainForm class

Re: subclassing MainForm class

Re: subclassing MainForm class

Re: subclassing MainForm class

Re: subclassing MainForm class

Re: subclassing MainForm class

Re: subclassing MainForm class

Re: subclassing MainForm class

Re: subclassing MainForm class

Re: subclassing MainForm class

Similar Threads

Compilation Error: base class undefined in the class created from UI file

class QHBoxLayout

How to use Signal through direct connection

Subclassing qbutton class

Memory error reading class attribute from private slot

Bookmarks

Bookmarks

Posting Permissions