Set specific values in a QSpinBox - qt

Question

I have a widget containing a QSpinBox. This widget also has a QVector<int> Values. What I would like to do is get the QSpinBox to display values issued from Values only.
At first I thought that a new slot and signal in my widget would do the trick, something like
slot :
void ChangeSomeValue()
{
// QVector<int> Values;
// int Index;
int val = Values[ Index ];
emit( SomeValueChanged( val ) );
}
connects :
connect( UI->MySpinBox, SIGNAL( valueChanged(int) ), this, SLOT( ChangeSomeValue() ) );
connect( this, SIGNAL( SomeValueChanged(int ) ), UI->MySpinBox, SLOT( setValue(int) ) );
But then several problems arise :
QSpinBox emit another valueChanged after I call its setValue, resulting in an infinite loop (until my QVector explodes).
I still have to find a way to keep track of Index, depending on which of the QSpinBox arrows was clicked (up or down... I don't even think this is possible).
So my solution, with its problems, seems to be a dead end. Any idea?. I'd like to stick to QSpinBox, if possible.
Thanks !
[EDIT]
Subclassing :
class SpinBox : public QSpinBox
{
Q_OBJECT
public:
explicit SpinBox(const QVector<int> & values, QWidget * parent = 0) :
QSpinBox(parent),
mValues(values),
mIndex(0)
{
qSort(mValues);
setMinimum(mValues.at(0));
setMaximum(mValues.at(mValues.size() - 1));
setValue(mValues.at(0));
}
protected:
void stepBy(int steps) // re-implementaion
{
mIndex += steps;
mIndex = qBound(0, mIndex, mValues.size() - 1);
setValue(mValues.at(mIndex));
}
private:
QVector<int> mValues;
int mIndex;
};

Answer 1

I Would suggest writing your own class to do it by sub-classing QAbstractSpinBox.
Maybe take a look at the accepted answer on this question:
How to subclass QSpinBox so it could have int64 values as maxium and minimum

Answer 2

QSpinBox emit another valueChanged after I call its setValue, resulting in an infinite loop (until my QVector explodes).
You can prevent this by using QObject::blockSignals(). Make sure to unblock signals afterwards.
I still have to find a way to keep track of Index, depending on which of the QSpinBox arrows was clicked (up or down... I don't even think this is possible).
Well, I suppose you can store the old value in a member variable, and when QSpinBox emits valueChanged(), you can compare the new to the old value to figure out whether the up or the down arrow was pressed.
That said, I don't know if that's enough to make QSpinBox behave like you want, correcting the value after it was changed once is a bit hacky. Subclassing QAbstractSpinbox might be better indeed.