Object::connect: No such slot QApplication::MYSLOT()

patowlmc

Well, I've searched this many times in Google, and still I can't solve it, so I ask for some help.

I've seen the documentation, and I think this is the way to declare a custom slot:

My H file:
@
#ifndef ACTIVIDADESTIC_H
#define ACTIVIDADESTIC_H

#include <QMainWindow>
#include <QMessageBox>

namespace Ui {
class ActividadesTIC;

}

class ActividadesTIC : public QMainWindow
{
Q_OBJECT

public:
ActividadesTIC(): manera() {}
explicit ActividadesTIC(QWidget *parent = 0);
~ActividadesTIC();

public slots:
void easy();

private:
int manera;
Ui::ActividadesTIC *ui;
};

#endif // ACTIVIDADESTIC_H

@

My main.cpp
@

void ActividadesTIC::easy() {
++manera;
if (manera>0) {
this->setWindowTitle("This is the easy way");
}
}

class MyWidget : public QWidget
{
public:
MyWidget(QWidget *parent = 0);
};

MyWidget::MyWidget(QWidget *parent)
: QWidget(parent)
{
setFixedSize(900, 700);

QRadioButton *easyWay = new QRadioButton (tr("Easy Way"), this);
    easyWay->setFont(QFont("Arial", 11));
    easyWay->setGeometry(10, 40, 150, 50);

   connect(easyWay, SIGNAL(clicked()), this, SLOT(easy()));

}

int main(int argc, char *argv[])
{

QDir setPath("Documents");
QApplication app(argc, argv);
    MyWidget widget;
    widget.show();
    return app.exec&#40;&#41;;

}

@

Well, what i do in the void easy() doesn't really matters, its just a test to see if it works, but I keep getting Object::connect: No such slot QApplication::easy() in ..\ActividadesTIC\main.cpp

So please, any help is welcome.

Zlatomir

The problem is at this line:
@connect(easyWay, SIGNAL(clicked()), qApp, SLOT(easy())); //the slot is in your class not in QApplication
@
So the correct 3rd argument of connect should be this (the instance of your class***):
@connect(easyWay, SIGNAL(clicked()), this, SLOT(easy()));@

LE:
***More correctly expressed: pointer to the instance

marsupial

The point is that easy() is not a slot of QApplication but of your own class ActividadesTIC. Thus you should write

@connect ( easyWay, SIGNAL(clicked()), this, SLOT(easy()) );@

Edit: I shouldn't let myself get distracted by something else while writing a post... Took 6 minutes to long :D

patowlmc

Ok, so I've updated the program (& the post, you can check the "new code above"), but now I get this error: @Object::connect: No such slot QWidget::easy() in ..\ActividadesTIC\main.cpp:38@

So now, i understand where's the problem. But how to fix it?

NOTE: I tried: @connect ( easyWay, SIGNAL(clicked()), ActividadesTIC, SLOT(easy()) );@
But it tells me: @expected primary expression before ',' token@

patowlmc

FINALLY!!!

Got it working guys.

Do you expect me to post the working code? I'm doing so anyway: (NOTE: some of it is in spanish)

O!! BTW: THANKS!!

MY H FILE

@
#ifndef ACTIVIDADESTIC_H
#define ACTIVIDADESTIC_H

#include <QMainWindow>
#include <QMessageBox>

namespace Ui {
class ActividadesTIC;

}

class MyWidget : public QWidget
{
Q_OBJECT

public:
MyWidget(QWidget *parent = 0);

public slots:
void easy();

private:
int manera;
};

class ActividadesTIC : public QMainWindow
{
// Q_OBJECT

public:

explicit ActividadesTIC(QWidget *parent = 0);
~ActividadesTIC();

private:
Ui::ActividadesTIC *ui;
};

#endif // ACTIVIDADESTIC_H

@

My main.cpp:
@
#ifndef ACTIVIDADESTIC_H
#define ACTIVIDADESTIC_H

#include <QMainWindow>
#include <QMessageBox>

namespace Ui {
class ActividadesTIC;

}

class MyWidget : public QWidget
{
Q_OBJECT

public:
MyWidget(QWidget *parent = 0);

public slots:
void easy();

private:
int manera;
};

class ActividadesTIC : public QMainWindow
{
// Q_OBJECT

public:

explicit ActividadesTIC(QWidget *parent = 0);
~ActividadesTIC();

private:
Ui::ActividadesTIC *ui;
};

#endif // ACTIVIDADESTIC_H

@

goetz

Please do yourself a favor and include the Q_OBJECT macro in all QObject derived classes (QWidgets and subclasses count in!). You will save you a big bunch of problems, even if you do not need the functionality in the first place. So, please remove the commenting // in the second class.

patowlmc

hahah, ok Thanks, And I'll do that from now and on

ReaMix

When you posted your solution, you pasted the header file in the cpp section. I am having the same problem and am unable to resolve. I would appreciate seeing your working cpp code, if you still have it on hand.

goetz

Please open a new thread and post your problem description with some code snippets there.

sushant

Error :----QObject::connect: No such slot QDialog::mydata()

My HeaderFile
#ifndef DIALOG_H
#define DIALOG_H
#include <QDialog>
#include<QLineEdit>
#include<QPushButton>

class Dialog : public QDialog
{

public:
Dialog(QLineEdit *);
QPushButton *apply;
QLineEdit *line2;
QLineEdit *oldLineEdit;
private slots:
void mydata();

};

#endif // DIALOG_H

cpp file

#include "Dialog.h"
#include <QVBoxLayout>
#include<stdio.h>
Dialog::Dialog(QLineEdit *ledit)
{
apply = new QPushButton("Apply");
line2 = new QLineEdit;
oldLineEdit=ledit;
QVBoxLayout *b = new QVBoxLayout;
b->addWidget(line2);
b->addWidget(apply);
setLayout(b);
QObject::connect(apply,SIGNAL(clicked()),this,SLOT(mydata()));
}

void Dialog::mydata(){
printf("Enter the slot");
QString str = line2->text();
oldLineEdit->setText(str);
}

IamSumit

hii Sushant......
It is inadequate --
QObject::connect(apply,SIGNAL),this,SLOT)); ?

sushant

hii sumit,
QObject::connect(apply,SIGNAL(clicked()),this,SLOT(mydata()));

dbzhang800

Hi sushant,

You forget add Q_OBJECT in your custom class.
Please wrap your code between <code>@ and @<code>

BTW,
You can start a new thread for your question next time.