how to make the smalll triagle visible and clickable of the QTreeWidgetItem, even it does not have a child yet?

[opengpu2]

how to make the smalll triagle visible and clickable of the QTreeWidgetItem, even it does not have a child yet?
and i want to dynamically add its child when i click on the small triangle there.

[Chris Kawa]

As suggested in the other thread showing a custom icon on a branchles item can be done with stylesheets.

As for clicking on it - it is reported as a click on a column 0 of the item. All there is to do then is to check where inside the item rectangle the click occured. Something along these lines:

connect(treeWidget, &QTreeWidget::itemClicked, [=](QTreeWidgetItem* item, int column){
    if(column == 0) {
        auto cursorPos = treeWidget->mapFromGlobal(QCursor::pos());
        if(cursorPos.x() < treeWidget->visualItemRect(item).x()) {// clicked on the branch area
            //do stuff e.g. add children to item
        }
    }
});