Adapt QMessageBox size to its text size - qt

Question

I would like to create a QMessageBox::critical which would automatically adapt its size depending on the size of the content (the message text). How can I do it?
This is the message I would like to display on the QMessageBox
std::wstring tmpStrEx;
QDomNode tmpNodeParent = node.parentNode();
while(!tmpNodeParent.isNull() && tmpNodeParent.nodeName().toStdWString() != L"root"){
std::wstring tmpStrTmp;
tmpStrTmp = L"<"
+ tmpNodeParent.nodeName().toStdWString()
+ L" nm=\""
+ tmpNodeParent.toElement().attribute(QS(_T("nm")), QS(_T("undef")) ).toStdWString()
+ L"> ";
}
QString mex = "Error while reading vector.<br/><br/>Please check in:<br/><br/> " + tmpStrTmp ;
tmpStrTmp can be something like <vct nm="name"> <vcx nm="xyz">
I tried in these ways to build the QMessageBox:
First a simple:
QMessageBox::critical(this, "Error", mex);
This shows half message without the content in tmpStrTmp like this:
Error while reading vector.
Please check in:
I thought tmpStrTmp was the problem but if I put only tmpStrTmp in the QMessageBox, it shows its content. So, I thought it was a problem of space and I tried these two ways:
1.
QMessageBox msgBox;
QSpacerItem* spacer = new QSpacerItem(500, 500, QSizePolicy::Minimum, QSizePolicy::Expanding);
msgBox.setTextFormat(Qt::RichText);
msgBox.setText( mex );
QGridLayout* layout = (QGridLayout*)msgBox.layout();
layout->addItem(spacer, layout->rowCount(), 0, 1, layout->columnCount());
msgBox.exec();
2.
QMessageBox *box = new QMessageBox::QMessageBox(QMessageBox::critical, "Error", mex);
QGridLayout *layout = qobject_cast<QGridLayout *>(box->layout());
if (layout) {
QTextEdit *edit = new QTextEdit(mex);
edit->setReadOnly(true);
layout->addWidget(edit, 0, 1);
}
box->exec();
delete box;
but without success...any help? thanks

Answer 1

If you don't want your QMessageBox to simply widen out with your text, and break a new line at some point, you should create an instance of QMessageBox and set it to have a fixed width (QWidget::setFixedWidth()).
Another option is to pass in a text string with new lines (\n) in it, and it can handle it nicely.
Also, if you are using an instance, you can tell it that you are using RichText, and pass in a subset of html markups QMessageBox::setTextFormat(Qt::RichText), or even just make sure you use a valid html tag before your first newline character.
Hope that helps!

Answer 2

QMessageBox is a grid. I'm not sure how to adapt QMessageBox size to its text size but if you know what is going to be appear in the messagebox you can most definitely set it to a minimum(actually fixed) size by this way:-
QMessageBox messageBox;
QSpacerItem* horizontalSpacer = new QSpacerItem(500, 0, QSizePolicy::Minimum, QSizePolicy::Expanding);
messageBox.setText( "Put text here" );
QGridLayout* layout = (QGridLayout*)messageBox.layout();
layout->addItem(horizontalSpacer, layout->rowCount(), 0, 1, layout->columnCount());
messageBox.exec();