(C++) Object::connect: No such slot QDialog::my_slot()

 

Compile warning.

 

 

 

 

 

Full warning message

 

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Object::connect: No such slot QDialog::buttonClicked() in ../MyFolder/main.cpp:40

 

 

 

 

 

Cause

 

Operating system: Ubuntu

IDE: Qt Creator 2.0.0

Project type: Qt4 GUI Application

Compiler: G++ 4.4.1

Libraries used:

• Boost: version 1.40
• Qt: version 4.7.0 (32 bit)

 

 

 

 

 

Qt project file

 

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#------------------------------------------------- # # Project created by QtCreator 2010-07-22T12:56:24 # #------------------------------------------------- QT += core gui TARGET = CppQtExample11 TEMPLATE = app SOURCES += main.cpp HEADERS += \ MyDialog.h

 

 

 

 

 

Source code

 

 

 

 

 

main.cpp

 

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#include <boost/scoped_ptr.hpp> #include <QtGui/QApplication> #include <QDialog> #include <QPushButton> #include <QVBoxLayout> #include "MyDialog.h" int main(int argc, char *argv[]) {   QApplication a(argc, argv);   boost::scoped_ptr<MyDialog> dialog(new MyDialog);   boost::scoped_ptr<QVBoxLayout> layout(new QVBoxLayout);   boost::scoped_ptr<QPushButton> button1(new QPushButton);   button1->connect(     button1.get(),SIGNAL(clicked()),     dialog.get(),SLOT(buttonClicked()));   button2->setText("Quit");   layout->addWidget(button1.get());   dialog->setLayout(layout.get());   dialog->show();   return a.exec(); }

 

 

 

 

MyDialog.h

 

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#ifndef MYDIALOG_H #define MYDIALOG_H #include <QDialog> class MyDialog : public QDialog {   public slots:     void buttonClicked() { } }; #endif // MYDIALOG_H

 

 

 

 

 

Solution

 

Add the Q_OBJECT at the beginning of the MyDialog class declaration.

 

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#ifndef MYDIALOG_H #define MYDIALOG_H #include <QDialog> class MyDialog : public QDialog {   Q_OBJECT   public slots:     void buttonClicked() { } }; #endif // MYDIALOG_H

 

Note that a complete example of the corrected version of this compile warning can be found at Qt example 12: creating a custom QDialog with slot.