QMessageBox: Controlling the width

[ChrisW67]

#include <QtGui>
#include <QDebug>
 
int main(int argc, char *argv[])
{
 
    QApplication app(argc, argv);
 
    QMessageBox msgBox1;
//    msgBox1.setMinimumWidth(400);  // seemingly ignored, always same width box
//    msgBox1.setFixedSize(QSize(400, 200));  // also no effect
//    msgBox1.setFixedSize(400, 200);
 
    QPushButton dw;
    dw.setFixedSize(100, 100);
    msgBox1.layout()->addWidget(&dw);
 
    msgBox1.setWindowTitle("Width 400");
    msgBox1.setText("<strong>Warning</strong>");
    msgBox1.setInformativeText(
        "You have not entered hours against this event<br /> "
        "Do you wish to save the event anyway?");
    msgBox1.setStandardButtons(QMessageBox::Yes | QMessageBox::No);
    msgBox1.setDefaultButton(QMessageBox::No);
    msgBox1.setIcon(QMessageBox::Warning);
    msgBox1.show();
 
    QMessageBox msgBox2;
//    msgBox2.setMinimumWidth(800);  // seemingly ignored, always same width box
//    msgBox2.setFixedSize(QSize(800, 200));
//    msgBox1.setFixedSize(800, 200);
    msgBox2.setWindowTitle("Width 800");
    msgBox2.setText("<strong>Warning</strong>");
    msgBox2.setInformativeText(
        "You have not entered hours against this event<br /> "
        "Do you wish to save the event anyway?");
    msgBox2.setStandardButtons(QMessageBox::Yes | QMessageBox::No);
    msgBox2.setDefaultButton(QMessageBox::No);
    msgBox2.setIcon(QMessageBox::Warning);
    msgBox2.exec();
 
    return app.exec();
}
 
// vi: sw=4 ts=4 et

#include <QtGui>
#include <QDebug>

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

    QApplication app(argc, argv);

    QMessageBox msgBox1;
//    msgBox1.setMinimumWidth(400);  // seemingly ignored, always same width box
//    msgBox1.setFixedSize(QSize(400, 200));  // also no effect
//    msgBox1.setFixedSize(400, 200);

    QPushButton dw;
    dw.setFixedSize(100, 100);
    msgBox1.layout()->addWidget(&dw);

    msgBox1.setWindowTitle("Width 400");
    msgBox1.setText("<strong>Warning</strong>");
    msgBox1.setInformativeText(
        "You have not entered hours against this event<br /> "
        "Do you wish to save the event anyway?");
    msgBox1.setStandardButtons(QMessageBox::Yes | QMessageBox::No);
    msgBox1.setDefaultButton(QMessageBox::No);
    msgBox1.setIcon(QMessageBox::Warning);
    msgBox1.show();

    QMessageBox msgBox2;
//    msgBox2.setMinimumWidth(800);  // seemingly ignored, always same width box
//    msgBox2.setFixedSize(QSize(800, 200));
//    msgBox1.setFixedSize(800, 200);
    msgBox2.setWindowTitle("Width 800");
    msgBox2.setText("<strong>Warning</strong>");
    msgBox2.setInformativeText(
        "You have not entered hours against this event<br /> "
        "Do you wish to save the event anyway?");
    msgBox2.setStandardButtons(QMessageBox::Yes | QMessageBox::No);
    msgBox2.setDefaultButton(QMessageBox::No);
    msgBox2.setIcon(QMessageBox::Warning);
    msgBox2.exec();

    return app.exec();
}

// vi: sw=4 ts=4 et

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and result is attached. Not sure it proves anything though.

[nish]

this proves that the messagebox is not calling setFixedSize() internally. So i think we cannot do anything..

the only way to debug now it to study qmessagebox.cpp and qmessagebox.h in, may be add these files to your project and debug, so that you can safely make some modifications.

[thePoet]

Turns out the layout box in the QMessageBox is a grid (or at least it is in 4.5.2). You can force the resize using a spacer this way:

QMessageBox msgBox;
QSpacerItem* horizontalSpacer = new QSpacerItem(500, 0, QSizePolicy::Minimum, QSizePolicy::Expanding);
msgBox.setText( "SomText" );
QGridLayout* layout = (QGridLayout*)msgBox.layout();
layout->addItem(horizontalSpacer, layout->rowCount(), 0, 1, layout->columnCount());
msgBox.exec();

QMessageBox msgBox;
QSpacerItem* horizontalSpacer = new QSpacerItem(500, 0, QSizePolicy::Minimum, QSizePolicy::Expanding);
msgBox.setText( "SomText" );
QGridLayout* layout = (QGridLayout*)msgBox.layout();
layout->addItem(horizontalSpacer, layout->rowCount(), 0, 1, layout->columnCount());
msgBox.exec();

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That will force the width to a minumum of 500, but it is allowed to be larger.