[Solved]Problem with incomplete type and forward declaration trying to add new file to project.

SetBetterPass

I am trying to add new file to my project, small find dialog but I have a problem I can't solve. Everything seems OK to me as I compare my header file for find dialog and for main window but anyway I am getting 4 errors
2 times invalid use of incomplete type and 2 times forward declaration. Code is here:
find.h
@
#ifndef FIND_H
#define FIND_H

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

namespace Ui {
class FindDialog; //here is forward declaration, reported twice
}

class FindDialog : public QWidget{
Q_OBJECT

public:
explicit FindDialog(QWidget *parent =0);
~FindDialog();

private :
Ui::FindDialog* ui;

public slots:

};
#endif // FIND_H

@
find.cpp
@
#include "find.h"

FindDialog::FindDialog(QWidget* parent) :
QWidget(parent),
ui(new Ui::FindDialog) //here is invalid use of incomplete type Ui::FindDialog
{
ui->setupUi(this); //and so here

}
FindDialog::~FindDialog(){
delete ui;
}
@
the same way I have it made in mainwindow but class name is MainWindow and it's public class of QMainWindow, not QWidget and it's working without any problems.
Can someone help me please?
Thanks. :)

Zlatomir

At a first look it seems ok, did you run qmake after you added the class?

LE: Also look into the file ui_find.h and see the name of the ui class that is in the Ui:: namespace //isn't it simple Find instead of FindDialog, you should have something like:
@
namespace Ui {
class FindDialog: public Ui_FindDialog {};
}
@

MuldeR

You have a forward declaration of "Ui::FindDialog" in your header file, yes.

But where is the actual declaration?

Of course you cannot create an instance of a class for which you have only a forward declaration!

In your .cpp file, you normally include the header file created by the "UIC":http://qt-project.org/doc/qt-4.8/uic.html...

--

[EDIT]

Okay, I just noticed that you include "ui_find.h" in your header file. I guess that is the UIC-generated header file.

If you do it like that, then you do not need a forward declaration at all!

But it's better to have a forward declaration, so you can move the include for the UIC header file to the .cpp file.

Also double check what class the UIC header file actually defines. I apparently is not Ui::FindDialog...

SetBetterPass

Thanks Zlatomir I looked into ui_find.h file and found the class name is Ui_Form, added it there and it works now.