qstring.h no such file or directory error!

[stampede]

Is the class header on the list of HEADERS in .pro file ? Check if you have moc_pushbutton.cpp somewhere in the build directories. I think the header is not moc'ed, so you get undefined references, make sure its in the list of HEADERS and run qmake/make again.
Btw. you don't have to use QObject:: for connections, pushbutton class is derived from QObject, so you can simply call connect(...).

[wenn32]

Is the class header on the list of HEADERS in .pro file ? Check if you have moc_pushbutton.cpp somewhere in the build directories. I think the header is not moc'ed, so you get undefined references, make sure its in the list of HEADERS and run qmake/make again.
Btw. you don't have to use QObject:: for connections, pushbutton class is derived from QObject, so you can simply call connect(...).

i am using code blocks IDE and i didn't find any .pro file in the project folder.so should i create a .pro file to get rid of the error??

[wenn32]

here is the main.cpp

#include <QApplication>
#include "pushbutton.h"
 
int main(int argc, char* argv[])
{
    QApplication app(argc, argv);
    pushbutton *button = new pushbutton("Dont click me");
 
    button->show();
    return app.exec();
}

#include <QApplication>
#include "pushbutton.h"

int main(int argc, char* argv[])
{
    QApplication app(argc, argv);
    pushbutton *button = new pushbutton("Dont click me");

    button->show();
    return app.exec();
}

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here is the pushbutton.h

#ifndef PUSHBUTTON_H_
#define PUSHBUTTON_H_
 
#include <QPushButton>
 
class pushbutton : public QPushButton
{
    Q_OBJECT
 
    public:
    pushbutton(const QString& text, QWidget* parent = 0) : QPushButton(text, parent)
    {
        connect(this,SIGNAL(clicked()),this,SLOT(change()));
    }
 
    public slots:
    void change()
    {
    if(this->text() == "Don't click me!")
    {
        setText("Click me!");
        return;
    }
        setText("Don't click me!");
    }
};
#endif

#ifndef PUSHBUTTON_H_
#define PUSHBUTTON_H_

#include <QPushButton>

class pushbutton : public QPushButton
{
    Q_OBJECT

    public:
    pushbutton(const QString& text, QWidget* parent = 0) : QPushButton(text, parent)
    {
        connect(this,SIGNAL(clicked()),this,SLOT(change()));
    }

    public slots:
    void change()
    {
    if(this->text() == "Don't click me!")
    {
        setText("Click me!");
        return;
    }
        setText("Don't click me!");
    }
};
#endif

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ok i did some research and this is what i did

first i runned the qmake -project with folder source as my project folder like

c:/document......../myproject>qmake -project

c:/document......../myproject>qmake -project

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then i got .pro file which has following data

##Automatically generated by qmake (2.01a) Thu May 5 16:40:27 2011#####
 
TEMPLATE = app
TARGET = 
DEPENDPATH += .
INCLUDEPATH += .
 
# Input
HEADERS += pushbutton.h
SOURCES += main.cpp

##Automatically generated by qmake (2.01a) Thu May 5 16:40:27 2011#####

TEMPLATE = app
TARGET = 
DEPENDPATH += .
INCLUDEPATH += .

# Input
HEADERS += pushbutton.h
SOURCES += main.cpp

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but still after doing that i am getting error as

obj\Debug\main.o||In function `pushbutton':|
C:\Documents and Settings\t\My Documents\project\sample\pushbutton.h|11|undefined reference to `vtable for pushbutton'|
C:\Documents and Settings\t\My Documents\project\sample\pushbutton.h|11|undefined reference to `vtable for pushbutton'|
||=== Build finished: 2 errors, 0 warnings ===|

obj\Debug\main.o||In function `pushbutton':|
C:\Documents and Settings\t\My Documents\project\sample\pushbutton.h|11|undefined reference to `vtable for pushbutton'|
C:\Documents and Settings\t\My Documents\project\sample\pushbutton.h|11|undefined reference to `vtable for pushbutton'|
||=== Build finished: 2 errors, 0 warnings ===|

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i am using code blocks IDE.
Now can you guys help me.where am i doing wrong?????

i also did qmake -makefile and got few makefiles even that is not solving the problem.

[stampede]

I've never used codeblocks, maybe its generating it's own Makefiles. Leave the IDE build system for now, good that you try to use the tools by hand - this way you can learn a lot more than by clicking on the IDE gui buttons.
Try to cleanup all Makefiles in your project directories, run qmake --project again, then qmake and make. Code looks ok, so I guess this is caused by some leftovers in build directories.

[wenn32]

Finally it works! if you just search all the threads i have started.you will see that all my threads where on signals and slots and now it works can't believe it!!!!!

anyways i am really feeling bad that i couldn't make it work with code blocks(it would have been easier)

anyways i have written a program that will do QMAKE -project,QMAKE & MAKE(when placed in the project file)(that's less burden!!!)

so thanks to all the people who helped me THANKS!