How to center a widget in QScrollArea? - c++

Question

Constructor:
ScrollArea::ScrollArea(...)
{
...
end = myItems.count();
for(int i=0; i<end; i++)
{
scrollItems.append(new ScrollItem(myItems.at(i), 0, width, i, this));
}
scrollArea->setWidget(this); //must be last for auto-scrolling to work
}
Member function:
void ScrollArea::updateSelection(int selection)
{
foreach(ScrollItem* item, scrollItems)
{
if(item->updateSelection(selection, 0))
{
scrollArea->ensureWidgetVisible(item);
}
}
}
After running ScrollArea::updateSelection, it looks like this:
I want it to look like this:
Google returns a mis-titled question (as far as I can tell: Place widget in center of QScrollArea) and a bunch of junk.

Answer 1

Still don't know why QScrollArea::ensureWidgetVisible doesn't work, even with explicit margins, but I found something that does:
void ScrollArea::updateSelection(int selection)
{
int item = -1;
int i = scrollItems.count();
while(i)
{
i--;
if(scrollItems.at(i)->updateSelection(selection, 0))
{
item = i;
}
}
if(item < 0)
{
return;
}
i = scrollItems.first()->height();
item *= i;
item += i / 2;
//item is now the position that should be centered
scrollArea->verticalScrollBar()->setValue(
item - (scrollArea->height() / 2)
);
}
So I'm basically brute-forcing what I want instead of having the library do it. (and fail)