The window in the task bar does not appear

[Mask]

Hi, I tried to open a new QMainWindow after logging in, but the program in the taskbar does not appear.

mainwindow.h

#ifndef MAINWINDOW_H
#define MAINWINDOW_H

#include <QMainWindow>
#include <QGraphicsScene>
#include <QtSql>

#include "home.h"

namespace Ui {
class Login;
}

class Login : public QMainWindow
{
    Q_OBJECT

public:
    explicit Login(QWidget *parent = 0);
    ~Login();
    void Wait(int Seconds);
    void LoadDatabase();
    void ShowHome();

    struct Users
    {
        QString Username;
        QString Password;
        int AdminLevel;
    } UsersInfo;

    QSqlDatabase database;

private slots:
    void on_Login_AccessButton_clicked();
    void on_Login_DeleteButton_clicked();

private:
    Ui::Login *LoginUI;
    Home *HomeUI;
};

#endif // MAINWINDOW_H

A part of mainwindow.cpp

hide();
HomeUI = new Home(this);
HomeUI->show();

Thank you all and sorry for my bad english.

[SGaist]

Hi and welcome to devnet,

What do you mean by: "the program in the task bar does not appear" ?

Also, why are you making your login widget a QMainWindow ?

What version of Qt are you using ?
What OS are you running on ?

[Mask]

Hi, thanks for the reply.
I mean that after making the Switch of QMainWindow the application disappears at the bottom and it is as if it were not executed and if I try to minimize it appears in a small window in the bottom left (if I have not explained, I send you a screen as soon as I go back from school).
I'm new to programming with graphics, but with the tutorials I saw, I noticed that everyone used the QMainWindow.
The version I use is 5.11 and I use it on Windows.

[jsulm]

@Mask Why don't you use QDialog for your Login instead of QMainWindow? Create QMainWindow only if log-in was successful.

[Mask]

@jsulm said in The window in the task bar does not appear:

@Mask Why don't you use QDialog for your Login instead of QMainWindow? Create QMainWindow only if log-in was successful.

I've just tried, the result does not change after login does not appear in the taskbar.

Thanks anyway.

[J.Hilk]

@Mask
my guess would be your homeui has no size defined and defaulted therefor to a size of 0x0

[Mask]

@J.Hilk
The quantities are defined, I also tried to set LoginUI as a window to open after login but nothing has changed.

An example of my problem:

[SGaist]

Can you show how you start your application and how you use your login widget ?

[Mask]

@SGaist
Of course.

secdialog.cpp:

#include "secdialog.h"
#include "ui_secdialog.h"

#include <QtSql>
#include <QCryptographicHash>
#include <QMessageBox>
#include <QtSql>

SecDialog::SecDialog(QWidget *parent) :
    QDialog(parent),
    SecDialogUI(new Ui::SecDialog)
{
    SecDialogUI->setupUi(this);
    SecDialogUI->Login_ErrorLabel->hide();

    setWindowIcon(QIcon(":/Image/mask.png"));
    LoadDatabase();
}

SecDialog::~SecDialog()
{
    delete SecDialogUI;
}

void SecDialog::LoadDatabase()
{
    QString driver = "QMYSQL";
    database = QSqlDatabase::addDatabase(driver);

    database.setDatabaseName("clients");

    database.setHostName("localhost");
    database.setUserName("root");
    database.setPassword("");

    if (!database.open() )
    {
        QMessageBox Error;
        Error.setText("Problemi di accesso al Database! \nContatta un'amministratore di rete.");
        Error.exec();

        exit(1);
    }

    database.close();
}

void SecDialog::Wait(int Seconds)
{
    QTime dieTime= QTime::currentTime().addSecs(Seconds);
    while (QTime::currentTime() < dieTime)
        QCoreApplication::processEvents(QEventLoop::AllEvents, 100);
}

void SecDialog::on_Login_AccessButton_clicked()
{
    if(!SecDialogUI->Login_ErrorLabel->isHidden() )
    {
        SecDialogUI->Login_ErrorLabel->hide();
        Wait(1);
    }

    QString Username = SecDialogUI->Login_UsernameInput->text();
    QString Password = SecDialogUI->Login_PasswordInput->text();

    if(Username == NULL || Password == NULL)
        SecDialogUI->Login_ErrorLabel->show();
    else
    {
        database.open();

        QSqlQuery QuerySQL;
                  QuerySQL.prepare("SELECT * FROM users WHERE username = '"+Username+"'");
                  QuerySQL.exec();

         database.close();

         if(QuerySQL.size() < 1)
             SecDialogUI->Login_ErrorLabel->show();
         else
         {
             QuerySQL.next();
             UsersInfo.Username = QuerySQL.value("username").toString();
             UsersInfo.Password = QuerySQL.value("password").toString();
             UsersInfo.AdminLevel = QuerySQL.value("admin_level").toInt();
         }

         QString CryptPassword = QCryptographicHash::hash(Password.toLocal8Bit(), QCryptographicHash::Md5).toHex();

         if(UsersInfo.Password == CryptPassword &&  UsersInfo.AdminLevel > 0)
         {
             this->close();

             MainWindowUI = new MainWindow(this);
             MainWindowUI->showMaximized();
         }
         else
             SecDialogUI->Login_ErrorLabel->show();
    }
}

Main.cpp:

#include "secdialog.h"

#include <QApplication>
#include <QtGui>

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

    SecDialog SecDialogPage;
    SecDialogPage.setWindowFlags (SecDialogPage.windowFlags () & (~Qt::WindowContextHelpButtonHint) );

    SecDialogPage.show();

    return a.exec();
}

secdialog.h

#ifndef SECDIALOG_H
#define SECDIALOG_H

#include <QDialog>
#include <QGraphicsScene>
#include <QtSql>

#include "mainwindow.h"

namespace Ui {
class SecDialog;
}

class SecDialog : public QDialog
{
    Q_OBJECT

public:
    explicit SecDialog(QWidget *parent = 0);
    ~SecDialog();

    void Wait(int Seconds);
    void LoadDatabase();

    struct Users
    {
        QString Username;
        QString Password;
        int AdminLevel;
    } UsersInfo;

    QSqlDatabase database;

private slots:
    void on_Login_AccessButton_clicked();

private:
    Ui::SecDialog *SecDialogUI;
    MainWindow *MainWindowUI;
};

#endif // SECDIALOG_H

Thanks for the help you are giving me.

[jsulm]

@Mask You shoud change your design: this dialog should not show the main window (in fact it should not know anything about main window). Do it like this:

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

    SecDialog *SecDialogPage = new SecDialog();
    SecDialogPage->setWindowFlags (SecDialogPage.windowFlags () & (~Qt::WindowContextHelpButtonHint) );

    SecDialogPage->exec();
    if (SecDialogPage->logedOn()) {
        MainWindowUI = new MainWindow();
        MainWindowUI->showMaximized();
    }

    SecDialogPage->deleteLater();

    int ret = a.exec();
    delete MainWindowUI;
    return ret;
}

[J.Hilk]

@jsulm said in The window in the task bar does not appear:
> MainWindowUI = new MainWindow(this);

parenting to this shouldn't be possible inside main~~

[jsulm]

@J.Hilk Thanks, corrected! Was a copy/paste :-)

[Mask]

@jsulm
What is "logedOn ()"?

[Mask]

I found a solution:

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

    SecDialog *SecDialogPage = new SecDialog();
    SecDialogPage->setWindowFlags(Qt::Window);

    if(SecDialogPage->exec() == QDialog::Accepted)
    {
        MainWindow *MainWindowPage = new MainWindow();
        MainWindowPage->showMaximized();
    }

    SecDialogPage->deleteLater();

    return a.exec();
}

Thank you all for the help you gave me.

[jsulm]

@Mask said in The window in the task bar does not appear:

What is "logedOn ()"?

It would be a method in your dialog implemented by you. Returns true when user has successfully logged on, else false.

[Mask]

@jsulm
But the "main.cpp" endlessly repeats an if until it's true?
Is it okay like I did?

[jsulm]

@Mask said in The window in the task bar does not appear:

But the "main.cpp" endlessly repeats an if until it's true?

No, it does not - I don't see any loop there.
The code you posted works if you only return QDialog::Accepted in case user was logged on successfully and exiting the app if not.

[Mask]

@jsulm
I know that no loops are set, but I'm wondering when the main executes that one. Does it only run after the accept () is called?

[jsulm]

@Mask "SecDialogPage->exec()" returns as soon as user closes dialog either by accepting (OK) or rejecting (Cancel).

[Mask]

@jsulm
Ah okay, thank you!