Close Modal QDialog manually without connecting a button - dialog hanging after code completes

Question

I am aware of the applications and use of modal dialogs(QDialog) and examples given all around the web, but my use is for displaying progress.

Have Tried:

As per threads/posts from here and here, I have found to use accept(), done(), close(), setResult() but none of these close the dialog, the dialog just hangs.

I have a connect() to "click close" but this does not fully satisfy the requirements, since a successful or unsuccesful execution will in either case await user input.

update: just tried setResult(Accepted);,QDialog remains hanging, even after successful execution.

Problem:

The modal dialog is used to show progress, at which the end of a succesful execution should close the modal dialog automatically, but if not executed successfully, the dialog should remain open for the user to view the displayed error.

Used functions:

I have used these above proposed functions. These do not close the dialog, the dialog just hangs awaiting user interaction (i.e. manaully closing it with a slot from a button)

CODE:

The dialog is executed with:

dlgConnectStatus = new LoginStatusDialog(login, key, auth);
dlgConnectStatus->setModal(true);
int res = dlgConnectStatus->exec();               << see note below
qDebug() << "dlgConnectStatus result = " << QString::number(res);

note: all code running the execution is in the dlgConnectStatus class contructor. This code is only executed once the dlgConnectStatus->exec(); is called, however no result is ever returned, the code finshes executing and hangs after the last constructor line.

I attempted adding :

if (Return_Object->getCode() == ReturnCode::netcon_LoginSuccess) {
    setResult(Accepted);
    accept();
}

but it still just hung!

*Finishing info (irrelevant but for putting into context):

After a code execution (successful or not), a public object is extracted from the dlgConnectStatus object before being destroyed.*

TL;DR

How can I close a QDialog, type modal, manually?

Bare/Essential Code for creating the issue

Calling Code:

dlgConnectStatus = new LoginStatusDialog(login, key, auth);
qDebug() << "Done LoginStatusDialog, setting modal";
dlgConnectStatus->setModal(true);
qDebug() << "Done setting modal, executing";
int res = dlgConnectStatus->exec();
qDebug() << "dlgConnectStatus result = " << QString::number(res);

//see below for debugger output -> the qDebug output

LoginStatusDialog.h

#ifndef LOGINSTATUSDIALOG_H
#define LOGINSTATUSDIALOG_H

#include <QDialog>
#include <QtCore>
#include <QtGui>
#include <QtWidgets>
#include <thread>

#include "returnobject.h"
#include "datamanager.h"

namespace Ui {
class LoginStatusDialog;
}

class LoginStatusDialog : public QDialog
{
    Q_OBJECT

public:
//    explicit LoginStatusDialog(QWidget *parent = 0);
    LoginStatusDialog( QString _login,  QString _key, QString *_auth_tok, QWidget *parent = 0);
    ~LoginStatusDialog();

private:

    Ui::LoginStatusDialog *ui;
    QString login, key;

    ReturnObject *Return_Object;

    void initGui();
};

#endif // LOGINSTATUSDIALOG_H

LoginStatusDialog.cpp

//custom constructor 
LoginStatusDialog::LoginStatusDialog( QString _login,  QString _key, QString *_auth_tok, QWidget *parent) :
    QDialog(parent), ui(new Ui::LoginStatusDialog), login(_login), key(_key)
{
    ui->setupUi(this);

    //this code is basically self explanitory
    Return_Object = new ReturnObject(ReturnCode::netcon_LoginSuccess, QString(""));

    if (Return_Object->getCode() == ReturnCode::netcon_LoginSuccess) {
        //by use ofbreakpoints, I can verify this close is reached but not executed.
        qDebug() << "pre close";
        close();
        qDebug() << "post close";
    }
}

Debug info

Debugging starts
Creating LoginStatusDialog
pre close
post close
Done LoginStatusDialog, setting modal
Done setting modal, executing
//remains open

Answer 1

Your check with close is doing in constructor, but exec is calling after it, so u need do something like timer in constructor and connect it's timeout signal with slot, that will contain your login check. Also, you can reimplement exec method for starting timer only after exec called.