Qt slot is not called

Question

I have shortened the code.
I have a main window with a button. The button opens another window to register someone's personnal information.
When I click on "Confirmer" it should trigger the confirmerInformations() slot. However nothing happens.
I don't understand why. I have no error log.

Sorry for the huge code but this problem makes me crazy. I don't understand why the slot in the first window works although the slot in the second window with the exact same syntax won't run the method confirmerInformations

main.ccp

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

    Principale fenetrePrincipale;
    fenetrePrincipale.show();

    return app.exec();
}

Principale.h

#ifndef PRINCIPALE_H
#define PRINCIPALE_H

#include<QApplication>
#include<QPushButton>
#include<QBoxLayout>
#include<QGroupBox>


#include"Inscription.h"
#include"Connexion.h"

class Principale: public QWidget
{
    Q_OBJECT
public:
    Principale();
public slots:
    void inscription();
    void connexion();

private:
    QPushButton * boutonInscription;
    QVBoxLayout * vboxPrincipale;
    QVBoxLayout * layoutPrincipal;
    QGroupBox * general;
    QGroupBox* groupPrincipal;


};
#endif // PRINCIPALE_H

Principale.cpp

Principale::Principale()
    {
        setFixedSize(250, 150);
        boutonInscription = new  QPushButton("Ouvrir un nouveau compte bancaire");
        vboxPrincipale = new QVBoxLayout;

        vboxPrincipale->addWidget(boutonInscription);

        general = new QGroupBox("Cliquez sur un bouton");
        general->setLayout(vboxPrincipale);

        layoutPrincipal = new QVBoxLayout;
        layoutPrincipal->addWidget(general);

        setLayout(layoutPrincipal);
        setWindowTitle("Bienvenue dans votre banque");

        connect(boutonInscription, SIGNAL(clicked()), this, SLOT(inscription()));


    }

    void Principale::inscription()
    {

        Inscription *uneInscription = new Inscription();
        uneInscription->show();

    }

Inscription.h

#ifndef INSCRIPTION_H
#define INSCRIPTION_H
#include<QWidget>
#include<QLineEdit>
#include<QPushButton>
#include<QGroupBox>
#include<QBoxLayout>
#include<QLabel>
#include<QFormLayout>

    class Inscription : public QWidget
    {
        Q_OBJECT

    public:
        Inscription();
    private:
        // Information personnellses
        QGroupBox* boxInformationsPersonnelles_;
        QFormLayout* formInformationsPersonnelles_;
        QLabel* labelNom_;
        QLineEdit* nom_;


        // Boutons
        QGroupBox* boxBoutons_;
        QHBoxLayout* layoutBoutons_;
        QPushButton* boutonConfirmation_;

        //Layout principal
        QVBoxLayout* layoutPrincipal_;

    public slots:
        void confirmerInformations();
    };

Inscription.cpp

#include"Inscription.h"
#include<QErrorMessage>
#include<QDebug>

Inscription::Inscription(){

    // Box Informations personnelles
        labelNom_ = new QLabel("Nom :");
        nom_ = new QLineEdit();

        boxInformationsPersonnelles_ = new QGroupBox("Vos informations personnelles");
        boxInformationsPersonnelles_->setLayout(formInformationsPersonnelles_);

     // Box boutons
        boutonConfirmation_ = new QPushButton("Confirmer");

        layoutBoutons_ = new QHBoxLayout();
        layoutBoutons_->addWidget(boutonConfirmation_);

        boxBoutons_ = new QGroupBox("Confirmation");
        boxBoutons_->setLayout(layoutBoutons_);


     // Layout principal
        layoutPrincipal_ = new QVBoxLayout();
        layoutPrincipal_->addWidget(boxInformationsPersonnelles_);
        setLayout(layoutPrincipal_);


    // Connexion des boutons
        boutonConfirmation_ = new QPushButton("Confirmer");

        connect(boutonConfirmation_, SIGNAL(clicked()), this, SLOT(confirmerInformations()));

}

//Slots

void Inscription::confirmerInformations(){
        QErrorMessage* erreurInformationsPersonnelles = new QErrorMessage();
        erreurInformationsPersonnelles->showMessage("Veuillez remplir toutes vos informations personnelles");

}

Answer 1

You allocate memory twice.

boutonConfirmation_ = new QPushButton("Confirmer");
//...
boutonConfirmation_ = new QPushButton("Confirmer");//why?

Remove one line.

Explanation. I want to add some short code which you can easily compile on your machine and show the problem:

QPushButton *ptr;           //just pointer
ptr = new QPushButton(this);//allocate memory, this is a parent
ptr->setObjectName("ptr");  //object name to find it in future
qDebug() << ptr;            //show ptr
ptr = new QPushButton;      //allocate memory again, but without parent
qDebug() <<  connect(ptr,SIGNAL(clicked()),this,SLOT(echo()));
                            //show that connection was succesfull
qDebug() << "new ptr"<< ptr << "old ptr" << this->findChildren<QPushButton *>("ptr");
                            //show new and old ptrs

Output:

QPushButton(0x28d726a8, name = "ptr") //our old ptr
true                                  //connection succesfull
new ptr QPushButton(0x28d726e8) old ptr (QPushButton(0x28d726a8, name = "ptr") )
//pay attention that new ptr and old has different adresses and names, it is 2 different buttons.

Conclusion: in your code you use old button which was not connected, so you slot never calls.