Closing a parent from a child

[Dummie1138]

Hi. I am having issues closing a parent from a child. Specifically, the issue I am running into is this, from passwordbox.cpp:

connect(this, SIGNAL(destroyed()), this->parent(), SLOT(close()));

I am attempting to close a parent "CalibrationSelect" from within a child "PasswordBox" when the password box is deleted without an input submitted. So far, I am unsure why this not signalling. Per my understanding, the destroyed signal should be released when PasswordBox is closed, meaning that the parent should receive the close slot.

I have not encountered any messages telling me this->parent does not have the close slot. Please let me know if more info is required.

I have the following code:

passwordbox.h

#ifndef PASSWORDBOX_H
#define PASSWORDBOX_H

#include <QDialog>

namespace Ui {
class PasswordBox;
}

class PasswordBox : public QDialog
{
    Q_OBJECT

public:
    explicit PasswordBox(QWidget *parent = nullptr, int type = 0);
    ~PasswordBox();
    enum{CalibMenu, ManualCalib};

signals:
    void passwordCorrect();

private slots:
    void passwordSubmitted();
    void passwordBoxClosed(int result);

private:
    Ui::PasswordBox *ui;
    int parentIndex;    //Remembers who's the parent, like 23andme

};

#endif // PASSWORDBOX_H

passwordbox.cpp

#include "passwordbox.h"
#include "ui_passwordbox.h"
#include "controller.h"
#include <qDebug>

const QStringList truePassword = {"CCCFP_SERVICE", "CCCFP_MANUAL"};

PasswordBox::PasswordBox(QWidget *parent, int type) :
    QDialog(parent),
    ui(new Ui::PasswordBox)
{
    ui->setupUi(this);
    this->setWindowFlag(Qt::WindowContextHelpButtonHint, false);
    //this->setWindowTitle("Input password");
    //Read password
    connect(ui->boxButton, SIGNAL(accepted()), this, SLOT(passwordSubmitted()));
    connect(this, SIGNAL(passwordCorrect()), this, SLOT(accept()));
    connect(this, SIGNAL(finished(int)), this, SLOT(passwordBoxClosed(int)));
    parentIndex = type;
    //Connect accepted to a seperate function too
    qDebug() << "pwBox";
}

PasswordBox::~PasswordBox()
{
    delete ui;
}

//Reads submitted pw
void PasswordBox::passwordSubmitted(){
     QString password = ui->passwordInput->text();
     if (password == truePassword.at(parentIndex)){
         qDebug() << "Yay! Password correct!";
         Controller::get()->passwordUnlock(parentIndex);    //unlocks the calibration stuff in controller
         emit passwordCorrect();
     }
     else{
         ui->boxText->setText("Password incorrect: please reinput");
         ui->passwordInput->clear();
     }
 }

//closes pwbox
void PasswordBox::passwordBoxClosed(int result){
    qDebug() << result;
    disconnect(this, SIGNAL(finished(int)), this, SLOT(passwordBoxClosed(int)));
    if(result == QDialog::Rejected){
        connect(this, SIGNAL(destroyed()), this->parent(), SLOT(close()));
        qDebug() << "closed:";
        //this->parent()->close();
    }
    this->close();
}

calibrationselect.cpp

//Set password box
void CalibrationSelect::setPasswordBox(){
    PasswordBox *passwordbox = new PasswordBox((QWidget*) this, PasswordBox::CalibMenu);
    connect(passwordbox, SIGNAL(passwordCorrect()), this, SLOT(unlockScreens()));
    passwordbox->open(); //NOTE Switch to open if possible.
}

calibrationselect.h

#ifndef CALIBRATIONSELECT_H
#define CALIBRATIONSELECT_H
#include "controller.h"
#include <QDialog>
#include "cccfpmenubar.h"
#include "passwordbox.h"

namespace Ui {
class CalibrationSelect;
}

class CalibrationSelect : public QDialog
{
    Q_OBJECT

public:
    explicit CalibrationSelect(QWidget *parent = nullptr);
    ~CalibrationSelect();

signals:
    void changeColor_signal();
    void passwordCorrect();

private slots:
    void on_pushButton_Return_clicked();

    void on_pushButton_CupCal_clicked();

    void on_pushButton_LidCal_clicked();

    void on_pushButton_PressureCal_clicked();

    void on_pushButton_PumpCal_clicked();

    void on_pushButton_MotorCal_clicked();

    void on_pushButton_FactorySettings_clicked();

    void on_pushButton_StirrerCal_clicked();

    void on_pushButton_airCal_clicked();

    void passwordSubmitted(); //Function that reads the contents of the pw

    void passwordBoxClosed(int);

    void unlockScreens(); //Unlock calibration screens

private:
    Ui::CalibrationSelect *ui;

    void setPasswordBox(); //Set password box

    PasswordBox passwordbox;    //((QWidget*) this, PasswordBox::CalibMenu)

    //void closeEvent(QCloseEvent*);
};

#endif // CALIBRATIONSELECT_H

[Christian Ehrlicher]

Apart from the strange design (why would a child need to know something about a parent - you already used it the correct other way around for the correct password so why another way in this case?) - I don't see where you delete your PasswordBox dialog - you only close it.

[Dummie1138]

@Christian-Ehrlicher Thank you, I was unaware that "deleting" in Qt and "closing" are two different concepts. In any case, I am attempting to close a parent "CalibrationSelect" from within a child "PasswordBox" when the password box is closed without an input submitted.

Slightly unrelated, the reason for my design is because I want to use passwordbox as it's own unit to be added to other files too, and I want to keep as many things within passwordbox class as possible.

[JonB]

@Dummie1138
I echo @Christian-Ehrlicher's comment, do you really want to close a parent from a child? Like in the real world, it should not be allowed to do that. I can't imagine a scenario where it's a good idea. Why can't parent close itself when child closes if that's what's wanted? For example, instead of

connect(this, SIGNAL(destroyed()), this->parent(), SLOT(close()));

it would be much more acceptable if parent did a connection like

connect(child, &ChildClass::destroyed, this, &ParentClass::close);
// or use eventFilter() from parent
// or subclass ChildClass and emit signal from closeEvent()