How to set maximum length for QInputDialog Text

Question

is it possible to restrict the length in a QInputDialog::getText ? For example, I want to restrict the length from the user input to 10 characters directly in the InputDialog. Unfortunately, there isn't a function like QInputDialog::setMaximum .

Here's my current code:

QString input = QInputDialog::getText(this, tr("Find"), tr("Enter text:"), QLineEdit::Normal, "", nullptr, Qt::WindowFlags(), Qt::ImhDialableCharactersOnly);

    if (input == "")
        return;
    else if (input.length() > 10)
    {
        QMessageBox::warning(this, tr("Invalid input", "Note #1"), tr("Input is too long."));

        // This is this function name (calls itself again)
        on_actionFind_triggered();
    }
...

Answer 1

Very easy with a signal/slot mechanism and a signal blocker...

#include <QApplication>
#include <QInputDialog>

int main(int argc, char *argv[])
{
    QApplication a(argc, argv);
    QInputDialog w;
    QObject::connect(&w, &QInputDialog::textValueChanged,
            [&w](QString text){ if (text.length() > 10) { QSignalBlocker s(w); w.setTextValue(text.left(10)); } });
    w.show();
    return a.exec();
}

Another posibility would be to find QLineEdit child of the dialog using and then assign a certain QValidator to it. I have not tested this but it should work as well. But then you would need to program the maximum length validator.

auto lineEdit = inputDialog->findChild<QLineEdit*>();
lineEdit->setValidator(validator);