Qt: How to display a Messagebox when you are within a function?

Question

I'm developing using the Qt Nokia SDK.

I'm having trouble displaying the buttons of a MessageBox, when trying to display a messagebox within a function. If i try to display it within the main window, there is no problem showing the buttons.

The mainwindow consist of a QStackWidget which holds different widgets.

Here is the code that works in main window:

QMessageBox msgBox;
msgBox.setText("Name");
msgBox.setInformativeText("Do you want to save your changes?");
msgBox.setStandardButtons(QMessageBox::Save | QMessageBox::Discard |
                          QMessageBox::Cancel);
msgBox.setDefaultButton(QMessageBox::Save);
int ret = msgBox.exec();

Here is the function and code that i run after receiving a response from a web request (The messagebox displays, but not the buttons.

void MainWindow::RequestReceived()
{
    QMessageBox *msgBox = new QMessageBox(this);
    msgBox->setText("Test");
    msgBox->setWindowModality(Qt::NonModal);
    msgBox->setInformativeText("Do you want to save your changes?");
    msgBox->setStandardButtons(QMessageBox::Save | QMessageBox::Discard | 
                               QMessageBox::Cancel);
    msgBox->setDefaultButton(QMessageBox::Save);
    int ret = msgBox->exec();
}

Anyone got an idea of what is happening?

Thanks in advance!

I can't reproduce your problem. There shouldn't be any. Are you sure you aren't interfering with the QMessageBox somewhere else? — Morten Kristensen, Mar 09 '11 at 15:35
Can't spot your problem, but if that is the exact code, make sure to fix that memory leak. — zkunov, Mar 09 '11 at 15:43
@netrom: Have you also added the QStackWidget to the MainWindow? — Ikky, Mar 09 '11 at 15:45
@Ikky: I guess you mean QStackedWidget and yes I have, no problems at all. — Morten Kristensen, Mar 09 '11 at 15:59
another problem: setWindowModality(Qt::NonModal) and then call with exec() — zkunov, Mar 09 '11 at 16:07
I'd certainly want to try with multiple other Qt versions. It sounds like a bug. — Wes Hardaker, Mar 09 '11 at 22:24
You create 1 message box with a parent widget and the other without. Don't know if that makes any difference in your case. — Stephen Chu, Mar 09 '11 at 23:20
hmm, weird... when i lanch the application on a device, the buttons are shown, but not in the emulator... — Ikky, Mar 18 '11 at 13:10

score 14 · Answer 1 · edited Nov 07 '11 at 18:47

14

Try this code.It will help you.

QMessageBox Msgbox;
    int sum;
    sum = ui->textEdit->toPlainText().toInt()+ ui->textEdit_2->toPlainText().toInt();
    Msgbox.setText("sum of numbers are...."+sum);
    Msgbox.exec();

edited Nov 07 '11 at 18:47

Rob W

341,306
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answered Nov 07 '11 at 18:44

Jayasankar.K

141
1
3

score 6 · Answer 2 · edited Apr 30 '18 at 19:34

Maybe this will help:

QMessageBox::StandardButton reply;

reply = QMessageBox::question(this, "Save", "Do you want to save your changes?",
    QMessageBox::Save | QMessageBox::Discard | QMessageBox::Cancel);

if (reply == QMessageBox::Save) {
    qDebug() << "Yes was clicked";
    // code for saving...
}
if (reply == QMessageBox::Discard)
{
    // toDo
}
if(reply == QMessageBox::Cancel)
{
    //toDo
}

This code will produce the following:

result

score 1 · Answer 3 · answered May 11 '11 at 07:07

1

Try changing this line:

QMessageBox *msgBox = new QMessageBox(this);

to

QMessageBox *msgBox = new QMessageBox(0);

answered May 11 '11 at 07:07

Muhammad Anjum Kaiser

3,947
1
18
18

2

Not setting a parent is never a good idea as it breaks the window stacking (how odd the consequences of that are depends on the platform). It's good practice too always pass a parent. – Frank Osterfeld Nov 07 '11 at 19:02
2

Plus, you don't get the QObject hierarchy-based memory management (so it leaks unless you manually delete). – Tamás Szelei Jul 14 '12 at 17:52

Qt: How to display a Messagebox when you are within a function?

3 Answers3