error No such slot QMainWindow::open()

[kavinsiva]

hi,

When i am running the following program i am getting following error

Object::connect: No such slot QMainWindow::open()

pls help me to resolve this one


my win.h Header File

#ifndef WIN_H
#define WIN_H
#include<QtGui>
class win : public : QMainWindow
{
public:
        win();
private slots:
                void open();
private :
        QPushButton *pb1;
};
#endif

#ifndef WIN_H
#define WIN_H
#include<QtGui>
class win : public : QMainWindow
{
public:
        win();
private slots:
                void open();
private :
        QPushButton *pb1;
};
#endif

To copy to clipboard, switch view to plain text mode 

my win.cpp file

#include"win.h"
#include<QtGui>
win::win()
{
    setWindowTitle("test Window");
    pb1=createLink(tr("& test"),SLOT(open()));
    pb1->setVisible(true);
    pb1->setGeometry(0,0,40,40);
    pb1->setText("test");
    QObject::connect(pb1,SIGNAL(pressed()),this,SLOT(open()));
}
void win::open()
{
    setWindowTitle("event occured");
}

#include"win.h"
#include<QtGui>
win::win()
{
    setWindowTitle("test Window");
    pb1=createLink(tr("& test"),SLOT(open()));
    pb1->setVisible(true);
    pb1->setGeometry(0,0,40,40);
    pb1->setText("test");
    QObject::connect(pb1,SIGNAL(pressed()),this,SLOT(open()));
}
void win::open()
{
    setWindowTitle("event occured");
}

To copy to clipboard, switch view to plain text mode 

[yogeshgokul]

You forgot Q_OBJECT macro.

[kavinsiva]

hi ,

i placed Q_OBJECT macro after compiling i am getting following error

main.o: In function `main':
main.cpp:(.text+0x5e): undefined reference to `vtable for win'
main.cpp:(.text+0x67): undefined reference to `vtable for win'
main.cpp:(.text+0xa5): undefined reference to `vtable for win'
main.cpp:(.text+0xae): undefined reference to `vtable for win'
win.o: In function `win::win()':
win.cpp:(.text+0x9c): undefined reference to `vtable for win'
win.o:win.cpp:(.text+0xa3): more undefined references to `vtable for win' follow
collect2: ld returned 1 exit status
make: *** [testWin] Error 1

[yogeshgokul]

class win : public : QMainWindow

Replace this line with this:

class win : public QMainWindow

class win : public QMainWindow

To copy to clipboard, switch view to plain text mode 

QObject::connect(pb1,SIGNAL(pressed()),this,SLOT(o pen()));

Replace this line with this:

QObject::connect(pb1,SIGNAL(pressed()),this,SLOT(open()));

QObject::connect(pb1,SIGNAL(pressed()),this,SLOT(open()));

To copy to clipboard, switch view to plain text mode 

Remove the space in O PEN.

void win: open()

Replace this line with

void win:: open()

void win:: open()

To copy to clipboard, switch view to plain text mode 

Notice Scope Resolution Operator.

And you never allocated memory to QPushButton *pb1; So it will lead to crash.

[wysota]

Rerun qmake after adding the macro to the class.