[Python] QListWidget drag and drop configuration: When to use the mode instead of the...

I'm learning how to setup drag and drop in the view-model framework description at Qt site. When applied to convenience views (QListWidget, QTableWidget, QTreeWidget), the documentation uses either (in original C++ version):

listWidget->setDragEnabled(true);
listWidget->viewport()->setAcceptDrops(true);


or:

listWidget->setDragDropMode(QAbstractItemView::InternalMove);


I'm unable to figure out whether setDragDropMode is a shortcut to set individual properties of the widget and which ones in addition of the two above, or it actually does more. I see using QAbstractItemView::InternalMove and QAbstractItemView:ragDrop both set DragEnabled and setAcceptDrops to true, but lead to a different behavior for the item (move vs. copy), so I know there is more behind the mode method. I would like to clarify this point in order to know when to use the mode method.

My questions:

• Are the two approaches equivalent?
• Which properties/attributes are actually set by the mode method?
• What are the use cases for each one?

I use Qt for Python if that matters.


As an example, if I create a list widget with each approach, it seems the result is perfectly equivalent (in this specific case):

from qtpy.QtWidgets import (QApplication, QWidget, QListWidget, QHBoxLayout)

class Window(QWidget):

texts = ['Sycamore', 'Chestnut', 'Walnut', 'Mahogany']

def __init__(self):
super().__init__()

lw_1 = QListWidget()
lw_1.addItems(self.texts)
self.print_props('When created', lw_1)

lw_2 = QListWidget()
lw_2.addItems(self.texts)

# Comparing
lw_1.setDragEnabled(True)
lw_1.viewport().setAcceptDrops(True)
lw_1.setDropIndicatorShown(True)
self.print_props('Using properties', lw_1)

# With
mode = lw_2.DragDrop
lw_2.setDragDropMode(mode)
self.print_props(f'Using mode ({mode})', lw_2)

layout = QHBoxLayout(self)
layout.addWidget(lw_1)
layout.addWidget(lw_2)

def print_props(self, text, widget):
print()
print(text)
print('drag:', widget.dragEnabled())
print('drop:', widget.viewport().acceptDrops())
print('mode:', widget.dragDropMode())


def main():
app = QApplication([])
window = Window()
window.show()
app.exec()

main()

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