Override following digits in QSpinBox - c++

Question

Is there a property in Q(Double)SpinBox that allows the user to override digits that are right of the curser, just by typing?
For example: If the spinbox shows 12.52 I click between 1 and 2. Now I type 3.45 to get 13.45

Answer 1

Just checked it out - even activating Insert mode on keyboard doesn't help.
Apparently, you'll have to subclass QSPinBox and override some QAbstractSpinBox functions - at least, keyPressEvent.
QAbstractSpinBox has a pointer to underlying QLineEdit - which has a cursor position property.

Answer 2

There is no property, you can go with your own implementation like this:
Header:
#include <QObject>
#include <QDoubleSpinBox>
class CustomSpinBox : public QDoubleSpinBox
{
Q_OBJECT
public:
explicit CustomSpinBox(QWidget *parent = nullptr);
void keyPressEvent(QKeyEvent *event) override;
private:
void updateTextField(const QString &text);
};
Source:
#include "CustomSpinBox.h"
#include <QKeyEvent>
#include <QLineEdit>
CustomSpinBox::CustomSpinBox(QWidget *parent)
: QDoubleSpinBox(parent)
{}
void CustomSpinBox::keyPressEvent(QKeyEvent *event)
{
auto isInt = false;
event->text().toInt(&isInt);
if (isInt)
{
updateTextField(event->text());
}
else
{
QDoubleSpinBox::keyPressEvent(event);
}
}
void CustomSpinBox::updateTextField(const QString &text)
{
auto lineEdit = this->lineEdit();
auto cursorPosition = lineEdit->cursorPosition();
auto lineEditText = lineEdit->text();
QChar currentChar;
if (cursorPosition < lineEditText.size())
{
currentChar = lineEditText.at(cursorPosition);
if (currentChar.isPunct())
{
lineEdit->cursorForward(false);
}
}
lineEdit->del();
lineEdit->insert(text);
}
But please note that the behaviour can be counter-intuitive. What if the value is 1,23? With that approach, you cannot enter any value bigger than 9,(9). Maybe it is what is expected, maybe it should not jump over the dot/comma unless the value before the punctuation mark has size length bigger than 2 digits (or 3 or any other number).