仅当鼠标位于 QTreeWidget 中的项目上时才显示禁止的光标

Question

我试图在将鼠标移到自定义 QTreeWidget 中的某个项目上时显示 Qt::ForbiddenCursor，但仅当放置位置为 QAbstractItemView::OnItem 时。这是代码

    void XProjectTreeWidget::dragMoveEvent(QDragMoveEvent * event)
{
    QTreeWidgetItem* pItem = itemAt(event->pos());
    if (pItem == nullptr)
    {
        return;
    }

    XTreeItem* dropItem = dynamic_cast<XTreeItem*>(pItem);
    if (dropItem == nullptr)
    {
        return;
    }

    XTreeItem::DropPosition drop;
    if (!getDropPosition(drop))
    {
        return;
    }

    auto items = selectedItems();
    if (items.count() == 0)
    {
        return;
    }

    auto dragItem = (XTreeItem*)items.first();
    if (!dragItem->checkMoveItemPossible(dropItem, drop))
    {
        QGuiApplication::changeOverrideCursor(QCursor(Qt::ForbiddenCursor));
        event->setDropAction(Qt::IgnoreAction);
    }
    else
    {
        QGuiApplication::changeOverrideCursor(QCursor(Qt::ArrowCursor));
        event->setDropAction(Qt::MoveAction);
    }

    QTreeWidget::dragMoveEvent(event);
}

bool XProjectTreeWidget::getDropPosition(XTreeItem::DropPosition& drop)
{
    DropIndicatorPosition dropIndicator = dropIndicatorPosition();
    switch (dropIndicator)
    {
        case QAbstractItemView::AboveItem:  drop = XTreeItem::Above; break;
        case QAbstractItemView::BelowItem:  drop = XTreeItem::Below; break;
        case QAbstractItemView::OnItem:     drop = XTreeItem::Inside; break;
        default: return false;
    }
    return true;
}

问题是忽略操作似乎适用于 AboveItem 和 BelowItem 具有相同类型的所有项目。 dragMoveEvent 当 DropPosition 为 OnItem 时，对于相同类型的项目，同时将光标悬停在这些项目上方时，调用 dragMoveEvent。

如何仅在鼠标处于 OnItem 时显示 ForbiddenCursor？

Answer 1

调用QTreeWidget::dragMoveEvent（事件）；在更改光标之前解决了这个问题。这是固定代码现在的样子：

void XProjectTreeWidget::dragMoveEvent(QDragMoveEvent * event)
{
    // moved this call from the end of the method
    QTreeWidget::dragMoveEvent(event);

    QTreeWidgetItem* pItem = itemAt(event->pos());
    if (pItem == nullptr)
    {
        return;
    }

    XTreeItem* dropItem = dynamic_cast<XTreeItem*>(pItem);
    if (dropItem == nullptr)
    {
        return;
    }

    XTreeItem::DropPosition drop;
    if (!getDropPosition(drop))
    {
        return;
    }

    auto items = selectedItems();
    if (items.count() == 0)
    {
        return;
    }

    auto dragItem = (XTreeItem*)items.first();
    if (!dragItem->checkMoveItemPossible(dropItem, drop))
    {
        QGuiApplication::changeOverrideCursor(QCursor(Qt::ForbiddenCursor));
        event->setDropAction(Qt::IgnoreAction);
    }
    else
    {
        QGuiApplication::changeOverrideCursor(QCursor(Qt::ArrowCursor));
        event->setDropAction(Qt::MoveAction);
    }
}

仅当鼠标位于 QTreeWidget 中的项目上时才显示禁止的光标

Show ForbiddenCursor only when mouse is OnItem in QTreeWidget

qt

drag-and-drop

qtreewidget

qtreewidgetitem