How to connect slot to QScrollBar::rangeChanged signal?

[Mikeeeeee]

Hi!
I using Image Viewer Example
How to connect slot to QScrollBar::rangeChanged signal?
It's not work:

connect(scrollArea, &QScrollBar::rangeChanged, this, &ImageViewer::updateSize);

[jsulm]

@Mikeeeeee said in How to connect slot to QScrollBar::rangeChanged signal?:

It's not work:

Why don't you say what happens?
Do you expect others to guess?
How does ImageViewer::updateSize signature look like?

[Mikeeeeee]

I want to get the QScrollBar status change signal and then I want to get different sizes of QScrollBar.

void ImageViewer::updateSize()
{

   /* qDebug()<<scrollArea->horizontalScrollBar()->value()
           <<scrollArea->horizontalScrollBar()->maximum()
             //<<scrollArea->horizontalScrollBar()->sliderPosition() //тоже, что и value
          <<scrollArea->horizontalScrollBar()->minimum()
         <<scrollArea->horizontalScrollBar()->pageStep();*/
}

[J.Hilk]

@Mikeeeeee
you should post your error message,

from the naming of things, my guess is, scrollArea is a QScrollArea not a QScrollBar

[jsulm]

@Mikeeeeee You are aware that rangeChanged has two parameters?
Also, you still don't want to tell us what is exactly the problem?! Error message?

[Mikeeeeee]

QScrollArea *scrollArea;

if i do this:

connect(scrollArea, &QScrollBar::rangeChanged, this, &ImageViewer::updateSize);

I get error: no matching member function for call to 'connect'
As with any change QScrollArea *scrollArea tun ImageViewer::updateSize()?

[Mikeeeeee]

Maybe I can use QWidget::changeEvent(QEvent * event)?
But this too not work:

void updateSize(QEvent * event);

[mrjj]

Hi
You are not using correct parameters.
its
rangeChanged(int min, int max)
so your slot should also have those.

void ImageViewer::updateSize( int min, int max )
{
...
and you say
connect(scrollArea, &QScrollBar::rangeChanged, this, &ImageViewer::updateSize);
but its not scrollArea that has rangeChanged, its its scrollbar
so it should be
connect(scrollArea->verticalScrollBar(), &QScrollBar::rangeChanged, this, &ImageViewer::updateSize);
and thats for the vertical scrollbar, thre is also a horizontal.