Connecting two sliders manually?

mrjj

@lansing
hmm yes, seems to take 3 ticks regardless.
Its handled here

void QAbstractSlider::wheelEvent(QWheelEvent * e)
{
    Q_D(QAbstractSlider);
    e->ignore();
    int delta = e->delta();
    if (e->inverted())
        delta = -delta;
    if (d->scrollByDelta(e->orientation(), e->modifiers(), delta))
        e->accept();
}

so maybe it depends on how mwheel is setup.

lansing

@mrjj

Ok now I got into a QSlider paradox...

I created the slider object in the ui, then I created a new slider subclass base on QAbstractSlider. Then in the ui I tried to promote the slider object to the new subclass, but in the "base class" selection, it doesn't have QAbstractSlider as a choice, so I chose "QSlider" and the program ended complaining about constructor doesn't match. But I have to use QAbstractSlider as the base class because Qslider doesn't have control for wheelEvent.

mrjj

@lansing
Are you sure ctor do match ?

lansing

@mrjj

It complains about setTickInterval being not a member of the class

Here's my new slider header

class NewSlider: public QAbstractSlider
{
public:
    NewSlider(QWidget * parent = nullptr);
}

SGaist

Hi,

Why inheriting from QAbstractSlider if you want to customise QSlider ?

lansing

@SGaist

Hi, because QSlider doesn't have access to wheelEvent, which is one of the thing I need.

mrjj

@lansing
Hi
QSlider also have
void wheelEvent(QWheelEvent * e)
you can just override it. (its a virtual function )

SGaist

I understand you want to reimplement the wheelEvent method but inheriting from QAbstractSlider means that you're going to reimplement also the painting, etc. to make your custom slider match the design of QSlider. On the other hand, subclassing QSlider and reimplement the wheelEvent there will reduce highly the work needed.

lansing

Oh it does have a wheelEvent...I was looking at the document and I couldn't find the word on the page, so I thought it doesn't have.

http://doc.qt.io/qt-5/qslider.html

SGaist

When in doubt look at the base class(s) implementation and/or the link named List of all members, including inherited members.

mrjj

@lansing
Pro Tip. ;)

If you right click your custom class name
alt text

You can easy see and insert functions from base

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